Don´t go too hard against Your teacher, I bet he means well. I am "selftought", too and that´s the problem. We develop nasty habits that could lead to damage or harm because no one corrected me. When I asked why my boss would rather take someone in who don´t know sqat but is interested he said "I´d rather fill up an empty bucket then pick the nasty pieces out of a full one." What I mean to say: You really might be wrong. Just because You know how to make chips that doesn´t mean You´re done learning. Teachers want You to know the right way, the safe way. Machining is dangerous, You can deviate when You´re experienced enough. You will break things, You will be in harms way. Teachers want You to keep all body parts hole. That´s why they nag. Just take it in, accept it. You´ll thank him at age when You have Your own shop and staff with all Your limbs intact.
@@LaLaLand.Germany well, TH-camrs vary too, not all are good just because they make film, I suspect as ever the skill lies in recognising who we trust and what for.
Lovely to hear a good South African accent.... I recently built a stone slicing machine and had trouble of chatter machining the ends of the mandrel to take the cutting disc. I made a lathe steady which has helped in the machining of the long shift but I will definitely use your methods to make a cleaner job.... thanks.
Great video on this issue, I'm a tool maker by trade and did my apprenticeship back in the early 80s, I only ever use auto feed on a lathe when I'm rough cutting, I aways hand feed for everything else and after 40 + years you get very consistent. We were never allowed to use auto feed when training even for rough cutting. We had to develop a steady consistent control by hand or else.
Using the machine feeds allows you to maintain MMR (Metal Removal Rate) as close to optimum as possible, and you only need approach the machine to withdraw the tool and return to the beginning for the next cut. That keeps you out of the firing line of those chips you're producing... No sensible person wants to spend any more of his working day crouching over a machine working the handwheels than is absolutely necessary... And carbides last longer under power feed. And the reason trainees don't get to use power feeds is that when they're distracted (by a hot chip burning through their delicate flesh, say, the manual feed stops automatically... under power, the saddle just keeps going... while the trainee attends to a minor injury...
Good video and modeling. It's a hard subject to talk about. Engineering 101, everything is a spring. You're a spring, every part of the lathe is a spring, the stock is a spring, and the cutting tool is also. You are cutting a spring with another spring.
I used a Bridgeport 50 years ago in highschool..... And once for 15 minutes about 5 years ago.... ...with my advanced machining knowledge and skill...... ...you just upped my game. 😁 Very interesting and easy to follow explanations. Thank you.
"Chatter" when turning "Thin Wall" tube can be sorted by stuffing the bore with wet rags. Boring thin wall tube, chatter can be sorted using a few strips of wood, held on the o/d with 'O' rings or even sticky tape. ('O' rings are best though)
If you need to add dampening, just turn on the flood coolant. If you need to add damping, on the other hand, you need to add stuff to change the resonance.
These are useful suggestions that I never thought of. Sometimes I just grip the tool with a pair of pliers, which changes the natural frequency, and that does help.
Superb! Yesterday, faced chatter on En8 on a fine and final cut. Tried the tool over-hang, chuck speed and hand feed and just about got away with it. Mind you, the lather is 100 years old...Great clear and informative video, I hope you are a teacher! From a wet England, Graham.
This is an incredibly well presented tutorial on this topic - thanks for the detailed explanation and study of each of the approaches to solving the issue.
I'm not much into manufacturing but I remember that there are 2 reasons for chatter: static instability or forced vibrations. The second one being more straghtforward as the chatter occurs at the frecuency of the force being applied to the tool, varying cut speed solves the problem in most cases. For the instability, it is mostly caused by the cut depth being increased and decreased due to the flexibility of the tool, holding mechanism... This last one could be solved by changing the shape of the cuting tool (u can see it in interior hole cutting tools), or how the tool is fixed. As many people suggested, even untightening a bolt, intermediate material in the holder or changing the lenght by grabing the tool in a different point can solve this problem also. All in all, nice illustrative video showing the chattering and a way to solve it, as you said, many times avoided to propose a consistent solution about.
The solder around a small boring bar and the annealed copper strip under the tool bit are excellent ideas. I have used lead strip on larger boring bars in the past with some success. I will try the solder trick next time I use the small boring tools. Well presented sir. One of teethings I have done on the past is vary the spindle speed if you have a variable speed arrangement on your machine to work around those pesky resonance frequencies. While It can be a bit of a pain in the backside, If nothing else it can get you through the job. Cheers
Variable speed spindles works well in industry. Normally pickups kick in that function immediately. Unfortunately the home workshop is less likely to have that function. Manual feed does something very similar. I couldn't get chatter when manually feeding because I would autocorrect before I could stop myself 😂 Thanks for the comment.
I keep a chunk of oil clay on my lathe specifically as a universal vibration dampener. It instantly takes care of most chatter caused by significant overhangs. It even works well on long, thin parts between centers.
Thanks for the hints. I spent a lot of time in a machine shop as a welder and noticed the copper underneath the tool but never thought anythinv other than it being a shim. Now I know the purpose for when I get my old leblond up and running again. 👍
Good video. Let me tell you about my secret trick for dampening high frequencies: tighten the tool holder screws less than usual. And if you have multiple screws, let's say 3 screws holding your tool, actually use only 2, the first one and the last one. Don't even touch the tool with the middle one. Tighten the first front screw normally, but not strong. The back screw, tighten barely. Just touching and applying the slightest pressure. I've been using those tricks to bore impossible bores, mostly on CNC lathes that tend to have super high harmonics because everything is so tight and rigid compared to manual machines
Huh, that’s really fascinating. I never would have thought of it but it makes sense, (OTOH, I just have a home-grade 12x36, so too much stiffness probably isn’t likely the problem it is with a high-end CNC :-)
Ahhhh to get soaked with coolant trying to keep your arm and wrench out of the danger zone while a CNC lathe is taking a deep pass making sure you don't accidentally loosen ALL of the clamp screws... the days before new machines got all serious about "safety features" 😆 I tune my boring bars the same way when I'm setting up just to get ahead of any chatter. You can get some pretty serious overhang like that
For the first time the right explanation of "chatter". The problem has an analogy with audio. Resonant Frequency (and it's harmonics), Damping, (external and internal) , Stiffnes, Mass, etc,etc, are items wich are the basic items when talking about acoustics and UNWANTED Frequencies (especially Loudspeaker Engineering). And chatter is an unwanted mechanical frequency. These unwanted frequencies can be mastered with the solutions mentioned in the video. The solutions are the same for audio . All these solutions (and more) are also known by audio professionals such as audioengineers and speaker builders .
Several things to try that have been alluded to by other commenters. First, try speeding up the spindle rpm to try to get away from the natural frequency of the work. Slowing down a notch on the rpm often doesn't get you far enough away from the natural frequency, but is worth a try. Second. If your lathe is capable of handling the loads, try using the recommended speeds and feeds in the Machinist Handbook (or similar reference) for production work. Sometimes on long unsupported work an increased feed rate will load the work so it won't chatter. The trick is to finish with a heavy cut to size if the coarse, but smooth finish, is acceptable. If you try to end with a light cut it will vibrate like all get out. The discussion in the video about the cutting tool profile is the reason I use cemented carbide tools instead of insert tooling. I can grind the cemented carbide to a sharp corner profile whereas, unless you have just the right insert, the insert will present too much cutting edge to the work for a small hobby lathe. Additionally, American made cemented carbide tools are just a couple of dollars apiece and last for years in the home shop. Cheers from NC/USA
I have had some luck with the brazed carbide tools, but I realized to get the more pointy tip required, on a small lathe, you could take, say, a left- handed tool & lay it on its side, and then you have less carbide to grind away to get the sharp tip for a right handed tool - and if you grind some top relief, you have the whole width of the carbide tablet for resharpening. Bonus if the carbide was sloped away from the cutting side because then you get some side relief when you tip it on its side, without grinding away a lot of carbide - or can mill the angle on the bottom of the tool shank. Using a coarse green wheel to rough things out with these, & the imported ebay brown diamond wheels seem to work pretty well, for the price.. Also experimenting with re-shaping used carbide inserts for this - I am suspicious that they are often a better grade of carbide.. Great video, was just having some disappointment with some chatter last night on my 10" Logan.. probably pushing it too hard.. although I was getting a really nice finish with a carbide shear tool with a fine feed rate, once I was done roughing (see Mr Pete, & other videos..)
For inserts equivalent of "sharp" cemented carbide, you can use 5 things to your advantage in the world of inserts. 1: prefer a small nose radius (0,2 to 0.4mm even for roughing, they are stronger than they used to be). 2: use CVD coated inserts instead of PVD coated, because the coating is less thick, which keeps the sharpness of the cutting edge. 3: use a positive tool geometry rather than negative, which decreases cutting pressure. 4: some inserts are ground after being coated to recreate a sharp edge, as well asuncoated inserts for finishing, and choose a light-cutting chipbreaker design. 5: rather than the common 5 degree rake angle, position your tool to have a neutral 0 degree rake, in this manner the force is directed 100% towards the spindle and radially, rather than towards/away from the workpiece, and this helps a lot
@@nutgone100 You saved me saying it. I get triggered by the incorrect use of the term... Because a manager I had at one time used to refer to "Brazed on carbide" tooling as cemented carbide, and reacted badly, when, tired of hearing it said, I corrected him... He didn't like my criticism of his trigonometry, either...
@@windrk_6754 and if you grind some top relief, you have... unnecessarily removed the nicely diamond lapped surface the manufacturer provided... And reduced the thickness of the carbide tip, and caused it to generate more heat in use. Carbide tool sharpening was a five stage progressive process when I learned it... Roughing to lapping... When you buy brazed on carbides, use them with the top/back/compound rake they came with. Just grind the front and side clearances as required. grind them as soon as you become aware they're dulling, so you needn't do to much grinding at any one time. Grinding front and side means you need only adjust the tool height a little, if anything, when you remount the tool. Grinding sooner, rather than later saves you the discomfort of handling a hot tool. Grinding the steel shank below the carbide with a coarse aluminium oxide wheel before grinding the carbide with a green grit silicon carbide wheel makes life easier, too, the silicon carbide not being called upon to remove material it wasn't constructed to... And... Don't grind chipbreaker grooves into the brazed on carbide tip. Yes, it does work, to an extent, but it weakens the tips, and reduces their life expectancy... Right grade, right shape, right rake, grind little and often, and not on the top, if it's avoidable. If a big flake of material's chipped off the top, you may have to grind the top, but it's a pain... C60MV was a good carbide roughing wheel, from memory, C120MV before diamond lapping (with a close dress) Open dress it for roughing if you haven't a coarser wheel... The bigger the grinding wheel the better, a small wheel tends to leave a "hollow" below the cutting edge. Grinding on the side of a straight wheel's frowned upon, and dressing it's a bugger anyway. Have, but seldom, used cup wheels for carbides. Not often found in general shops...
Thank You SO MUCH for this clear and very informative video. I use a Chinese Sieg lathe normally and have just got boss of that but on my Peatol / Taig Micro lathe I was getting chatter marks even though the tool I had ground seemed to cut well. Then I tried t strip of copper cut from a pipe and annealed and placed under the tool. Using all the same speeds and feeds and it was like a different machine, suddenly everything has come right Brilliant!
The chatter can also be from work hardening the surface. I had a heck of a time cutting 4140 on my small craftsman lathe which is by no means a real rigid lathe. The cut was mush better when I slowed the spindle speed as slow as possible and took slightly deeper cuts.
Great info, it'll be of much use to me I'm sure. One thing I'll add that can sometimes help but isn't actually possible on a lot of machines is to bump the speed up and down. My old raglan with its variable speed drive held me out sometimes but I'm sure the tips in this vid will do a better job, thanks!
I was a manual lathe operator for about 15 years and turned down a lot of long pieces even longer than what was shown here. One time, a man said to add some rubber bands around the piece being turned and I was amazed that the chatter went away.
I think we all grasp the meaning of what the guy is trying to say without the need for pedantics , this is a lathe tutorial not a grammar lesson , life is too short . 😬
@@deancooper7952 and THAT attitude is how you end up with an entire generation unable to express themselves accurately, making for misunderstandings, inefficient communication in the work place, etc. Sit down.
@@deancooper7952,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, grammer is as vital as the accuracy of math,,,,,,,,,,,,,,,,,you must be a dem,,,,,,,,go vote for sleepy joes people
Thank you for this video it was very informative. I Am brand new to the world of Machining so any helpful information like this is very much appreciated.
Look up model engineering techniques, this is where you find the best information for the home workshop. Very rewarding hobby! Enjoy, and thanks for the comment...
How many of have ever do this: Take something like suger size chips and place a few on the tool tip, the tool holder, the toolpost,the lathe Bed, the lathe headstock, and then cut/turn(Notice Depth/Speed)...and watch where these particles moves/vibrates......I would say that a very practical way to zoom in on where to start.-? The cutting tool geometry is interesting above everything else, and the thing about Above Centre, On Centre, below Centre+Tool flex, . Now if you slightly above centre, if the tooltip goes into the work, the something has to give bend /flex or just cut. So if you change the tooltip geometry, it may just cut well with no vibration frequency generated, or you shift the frequency/vibration away from the tooltip into the work, which may or may not absorb it........
Don't forget about the natural frequency of the work you are turning. It is loading and unloading and deflecting too. Also the section is reducing in diameter changing its stiffness. The RPM is also a forcing factor....pulsing the RPM while cutting could keep chatter from forming and repeating.... better solve for the eigenvalues!😂
Nice video, what also works is to rotate your tool, and of course run your lathe ccw, your tips are for a craftmanship basic knowledge. At least when I started at a lath 35 years ago a old craftsmanship trained me al this tricks.
Very useful and insightful video. To add, the same principle applies to the work piece, less stick out from the chuck for unsupported material and if longer cuts are needed to make sure the part is supported on a live center and to add a steady if possible. What I have also experienced while parting specifically was that the length of material on the back of the chuck(sticking out into the spindle) will also cause chatter if it is left too long. This means you want to not only part of as close to the chuck as possible, but at the same time, use a short as possible piece of material. In my case I was parting 22mm material while making 15mm long parts. If I rough cut my lengths of stock more than about 250mm on the saw, I suddenly had issues with chatter while parting. This would gradually go away as I'm removing new parts from the stock and as it started to get shorter. Between 250mm and 270mm was the sweetspot, anything longer and the chatter will appear. Naturally this will all be related to the thickness of the material which will be stiffer the thicker the stock is meaning that more stick out is possible.
Very excellent approach and knowledge - i am pleased you created the video. You often refer to damping - which in principle is a resistance force added to the vibration to reduce its amplitude (and consequently reduce frequency as a secondary effect.) Most of the examples you gave change the driving frequency (pointed tool) or the natural frequency of the assembly. For instance the lead solder likely adds a secondary natural frequency whilst the copper likely reduces the natural frequency. I look forward to seeing more of your videos
damping is about turning oscillating energy into heat, out of the oscillating mechanism - which is what chatter is - an oscillating tool/work interaction.
It's rare that I have encountered chatter, and on a regular lathe, I first check the length of the tool bit, reducing the overhang as much as possible. If there is still chatter, slow the RPM down. Then reshape and sharpen the cutting edge. Make sure that the piece is mounted securely so it can't move about while under load. Make sure that the gibs aren't too loose. Use some lubricant. Loose headstock bearings can create chatter. On a brake drum and rotor lathe, use the dampers that came with it to get rid of harmonics and the chatter that ensues. Small drums and rotors don't get much chatter generally speaking, but bigger ones do more often. The design of some brake rotors chatter more than others. If you still get chatter with cast iron, change out the tool tips.
Very interesting, nice video, animations and explanation. From my experience, we have bent/broken Sandvik antivibration boring bars, these things kept screaming and breaking inserts no matter what but we urgently needed them to rough out big stainless cylinders. After some time trying, I just took a single massive cut (3.5mm) on low cutting speed and bit higher feed and it worked. The insert life was not awesome but lasted 20-25 minutes in-cut and managed to survive one part. The finish was horrible but it was just a roughing operation. I tried the same with external tools and it worked too few times. Just take bigger DOC, so the tool bends down and doesn't spring back. Just be careful not to break it into two.
From my experience on small lathes I have found that varying the feed and speed can eliminate most chatter but it needs to be done continuously. Once you settle on a particular feed/speed then it's not long before the sympathetic inherent harmonic vibration creeps in. I have in desperation twiddled the speed control on the VFD back and forth to kill any build up of vibration especially when cutting hard bronze with a fine cut. The tool attempts to skate on the surface instead of cutting and this causes the tool pressure to change and then it will dig in and the whole cyclic performance repeats at an annoying frequency. A rigid and narrow cutting surface along with a sharp edge and a suitable speed and feed will get you through most situations. Tubes can be stuffed with cloth for outside turning and for inside turning your damping wire is a good addition to the long thin boring bar. I find that turning stainless steel tubes to be the most difficult and I will try your dampening wire along with weights attached to the outside of the tube with Jubilee clips. Thanks for making this video but I think you have a few more tips to convey on this subject - the bane of every machine turner!
Someone suggested getting away from the resonant frequency by increasing rpm. In fact, You want the rotating frequency (revs per second) to be an integer multiple or division of the resonant frequency (herz). This way the tool 'bites' into the workpiece at the same angle as it rotates. So either decrease of increase rpm untill you find the sweet spot. There are many.
If I get chatter I change the speed of feed or the speed of rotation or cutting tip design or distance cutting tip is out and sometimes rest a drift punch on the cutting tip for dampening. The last thing I want to do is not use auto feed. It's bad enough that I have to do angle cuts manually as my Chinese lathe doesn't have that feature. I do really like that lead solder wrap. Good idea!
This was always our first approach too! Simple method and most times very effective. We had a large crate with thousands of different O-rings for this. And a whole bunch of short steel tubes that could be "rolled/clamped" over the O-rings. In some cases this helped solving impossible cases.
Sometimes I let a wrench or dead blow hammer ride on the turning part to damp the chatter. That is usually my first move because it doesn't involve stopping.
Ah... that'll work! Sounds like you an old hand with machining, I would be hesitant to suggest this to a novice. This is for the advanced class... @@billshiff2060
@@Lukers_tinkering Yeah it can be finicky finding the antinode of both the part and the wrench/hammer and make them cancel out. Just stay away from the chuck jaws and don't get between the rotating part and the tool post.
Another way to visualize the damping effect on a vibration system is when you put your hand on the system and it eases. Obviously on something safe, like washing machine or a small motor. Since you cant put your hands on the tool, a wire of such sorts is a viable solution. Interesting to think are there tool holders in the market incorporating this method? Like adding springs and pads to soften vibration?
It's all about tool pressure/cutting force and harmonics. Using a smaller nose radius almost always helps. Using a more negative lead angle with a positive rake angle is the way to go as it takes less pressure off the part and into the center of the cutting tool. Sandvik has good literature on this as well as a FREE course on their website. The spring you put on it slightly damps the vibration too.
The wide profile tip allows the chatter to build up as the tool goes back over its chatter from previous rotations of the part. A sharper profile and faster feed both reduce this problem. The frequency of your chatter seems too low for tool chatter. I think its the workpiece flexing. Just keep in mind everything involved in the operation from the workpiece to the tool and the lathe has some flex and can chatter especially if natural frequencies match.
What a great subject! Your video really made me think about this. You talked about changing the natural frequency of the tool and introducing dampening. Another place to look is where the chatter is created: the angular distance between the cutting edge digging in and getting released. Increasing the RPM causes the angular distance to be covered in a shorter time, increasing the frequency. Increasing the depth of cut will lengthen the angular distance to the release point, lengthening the time and lowering the frequency. Of course, the material plays a role as well in how deep the tool can dig in (harder material will increase the frequency) and the force at which the material releases the cutting edge (softer material will also increase the frequency). Also, we need to consider the natural frequency and vibration amplitude of the workpiece. As you say, it’s a complex mechanical system with many degrees of freedom…
True, but the idea of increasing the feed or depth of cut is to decrease the spring back thus effectively reducing the chatter. Essentially you keeping the tool down, albeit by fractions... You also adding a certain amount of dampening and this has to do with the size of the chips and the localised deformation at the cutting edge...
Agree completely. You’re focused on reducing amplitude while I was thinking more about avoiding resonance. But on the lathe, the frequency of the workpiece changes constantly, so my approach is probably more valid for the mill
On my 9 inch south bend I eliminated the chatter by using a 3 phase motor and an inverter from Amazon. Turns out the single phase motor which hummed like a washing machine was making vibrations in the whole lathe. Also by using the inverter It's possible to vary the rpms with the turn of a knob.
I only get chatter when facing on my chinese lathe. Shortening the tool overhang and making sure all slides are free from shake sometomes gives a fair cut but some of the problem I think comes from the speed control that pulses the drive motor and adds different vibration characteristics. I have used really old worn out lathes with smooth drive belts and obtained very neat and smooth facing despite all the wear on the machines.
Hi sir, Can you please make a video to guide you in performing finite element analysis simulation on boring tool when machining, I really want to learn from you, thank you for making this video.
The only way i really got away from chatter is changing the cutting geometry by stop thinking as it digging Into the part but running towards the head stock as you cut.. i paid too much attention to sharpening the edge towards the part. When i started grinding the tool so it cut towards the headstock i helped the chatter a lot even with tiny cuts i now get no chatter.
Look up model engineering techniques, this is where you find the best information for the home workshop. Very rewarding hobby! Enjoy, and thanks for the comment...
Why is nobody mentioning the fact the the tool is WAY stiffer than the workpiece. That long, thin, mild steel workpiece being worked right in the middle is certainly deflecting FAR more than the short, fat, really hard tool. The 'anti chatter wire' is a red herring that has no business in this video. I'm very interested in the ideas that the shape of the tool and the aspect of the work matter a lot, but the former was clouded and the latter ignored in this video.
Got a sub and a like for this vid alone, sir ! I made a solid toolpost for the cross slide (no compound ) and this made a big difference in the rigidity of my small lathe... I also dislike carbide-insert tooling on small lathes as the large(ish) nose radius tends to result in chatter, the comparatively blunt edge carbides usually have (positive rake) doesn't help matters either. 🙄 😎👍☘️🍺
I’m a time served welder of 50+ years and I remember once working in a workshop that had welding, fabrication and machining equipment and one of the turners in the machine shop was profoundly deaf and he worked by using the feeling of the vibration of his machine to know the finish that his machine was producing, the only problem was that he would have his lathe screaming high pitched and when anyone pulled him up about it he’s would hold his hands up and apologise only to turn around pissing himself and pop out another bang on job 😂
Great insights! The length of the stick out changed the frequency. I had flashbacks to Dr. Wells lecturing about vibrations, except i wish you had taught that class. Dr. Wells did a terrible job of showing how systems vibrate and how to detect the frequency and dampening. There was always a "c" factor, but did he ever explain how you find that? Or, how to predictably change it?
I cut a lot of stainless heavy wall tubes. 24-28” length. I was having issues of poor finish in the middle and used an indicator to check if the center of the part was whipping a bit. It was so I slowed the part down but then found the lack of tool pressure was giving a poor finish not chatter but poor surface finish, research revealed the stainless likes some cutting pressure. So I tried one with more shear better but not great. I added the steady rest in the center which improved the cut but matching the finish in the center is difficult.any suggestions would help.
That's a very specific condition, and I hope this isn't a commercial venture... that length you should be using a traveling steady. Check tool height along whole length of cut. Your depth of cut has to be more than the tip radius assuming you are using tip tools, and the chip breaker is very specific for stainless. What can also help is to plug the tube with wood or soft plastic, basically you machine the plug to a easy fit, cut the middle 45 deg and machine a bolt hold. If you tighten the two pieces it will plug the tube snug. This will add massive dampening and should solve your problem!
What would you recommend if modifying the tool holder and tool bits solve the problem but the vibrations also appears in the shaft you are machining? Base on my experience when you install the follower rest there is a tendency to solve the problem but upon removing the follower rest I somehow notice a deflection or bending of the shaft causing it to misalign again specially for small cross sections of diameter in the middle? any comments pls will be helpful. Thanks.
I'm sorry but its very difficult to help without hearing the feedback and checking the setup. From what you wrote the first place I would look is tool height, or bed deflection. It sounds like the tool is climbing. Also check the cutting point and make sure its sharp.
This was an interesting video. I was hoping you would go into the theory a little deeper though. Also, what's the 4th mode of vibration of the tool? I can only think of three.
The second derivative of position with respect to time is acceleration. The third derivative of position with respect to time is called 'jerk'. I heard the hubble telescope had specifications up to the seventh derivative. Now I feel like now I know why!
It would have been better if you at first changed the tool geometry then added the ant chatter wire. That surely would have been more accurate way of showing each method. We used to you magnets or simple elastic bands depending on access needed for the tool. We were also taught that you keep the tool at its shortest tool overhang for each tool needed. You could also change speeds and feed rates to eliminate the chatter.
Go to Open Source Machine Tools and learn how to use a lathe. Also overseas lathes need to be completely disassembled, cleaned, lubed, reassembled and then finally adjusted properly. Then come the mods to almost eliminate deflection. My G0752 never chatters unless Im being scared with the parting tool and using too slow of a feed rate. As soon as I grow a set and speed up the parting tool the chatter disappears. 99.9% of deflection on overseas lathes comes from operator error. Make chips that dont need dips! Forge On!!!
USE a STEADYREST ! Or FOLLOWER REST , Keep the cutting tool SHARP , Use Cutting oil and Feed the Tool Slowly . It all depends on DIAMETER , Type of material your Turning , and Many other Factors as well .
Hola, saludos desde Argentina, en herramientas de interior hago que sean mas largas en la parte de atrás, y en ese saliente le pongo un buje de bronce, y solucioné el problema de la vibración
I'd like to see you film that chatter in real time with a million frame per second v2511 Phantom camera. I'll check my Poweball ticket in the morning and let you know if you're going to be able to do that. 😁
As a self taught machinist I have terrible trouble with my teacher, so your putting the practical problems on a sound footing is really very helpful.
I have the same problem with my teacher 😅
@@thigtsquare950 what’s really frustrating is that the three people who could have taught me most are long dead!
Great comment
Don´t go too hard against Your teacher, I bet he means well. I am "selftought", too and that´s the problem. We develop nasty habits that could lead to damage or harm because no one corrected me. When I asked why my boss would rather take someone in who don´t know sqat but is interested he said "I´d rather fill up an empty bucket then pick the nasty pieces out of a full one."
What I mean to say: You really might be wrong. Just because You know how to make chips that doesn´t mean You´re done learning.
Teachers want You to know the right way, the safe way. Machining is dangerous, You can deviate when You´re experienced enough.
You will break things, You will be in harms way. Teachers want You to keep all body parts hole. That´s why they nag.
Just take it in, accept it. You´ll thank him at age when You have Your own shop and staff with all Your limbs intact.
@@LaLaLand.Germany well, TH-camrs vary too, not all are good just because they make film, I suspect as ever the skill lies in recognising who we trust and what for.
As a father of daughters there is no way to eliminate chatter, but I can go to my workshop and attenuate it some what.
😂😂😂
So agree with that!!!
You opened my eyes, thanks and it is a pleasure to listen to videos with no lousy music in the back ground !
THIS.
Lovely to hear a good South African accent.... I recently built a stone slicing machine and had trouble of chatter machining the ends of the mandrel to take the cutting disc. I made a lathe steady which has helped in the machining of the long shift but I will definitely use your methods to make a cleaner job.... thanks.
Great video on this issue, I'm a tool maker by trade and did my apprenticeship back in the early 80s, I only ever use auto feed on a lathe when I'm rough cutting, I aways hand feed for everything else and after 40 + years you get very consistent. We were never allowed to use auto feed when training even for rough cutting. We had to develop a steady consistent control by hand or else.
Using the machine feeds allows you to maintain MMR (Metal Removal Rate) as close to optimum as possible, and you only need approach the machine to withdraw the tool and return to the beginning for the next cut. That keeps you out of the firing line of those chips you're producing... No sensible person wants to spend any more of his working day crouching over a machine working the handwheels than is absolutely necessary... And carbides last longer under power feed.
And the reason trainees don't get to use power feeds is that when they're distracted (by a hot chip burning through their delicate flesh, say, the manual feed stops automatically... under power, the saddle just keeps going... while the trainee attends to a minor injury...
Good video and modeling. It's a hard subject to talk about. Engineering 101, everything is a spring. You're a spring, every part of the lathe is a spring, the stock is a spring, and the cutting tool is also. You are cutting a spring with another spring.
I used a Bridgeport 50 years ago in highschool..... And once for 15 minutes about 5 years ago....
...with my advanced machining knowledge and skill......
...you just upped my game. 😁
Very interesting and easy to follow explanations. Thank you.
"Chatter" when turning "Thin Wall" tube can be sorted by stuffing the bore with wet rags. Boring thin wall tube, chatter can be sorted using a few strips of wood, held on the o/d with 'O' rings or even sticky tape. ('O' rings are best though)
If you need to add dampening, just turn on the flood coolant. If you need to add damping, on the other hand, you need to add stuff to change the resonance.
😂😂😂...but yes, your are correct.
These are useful suggestions that I never thought of. Sometimes I just grip the tool with a pair of pliers, which changes the natural frequency, and that does help.
Superb!
Yesterday, faced chatter on En8 on a fine and final cut. Tried the tool over-hang, chuck speed and hand feed and just about got away with it.
Mind you, the lather is 100 years old...Great clear and informative video, I hope you are a teacher! From a wet England, Graham.
This is such a well presented video on a problem that seems to plague all home machinists, subscribed, cheers!!
This is an incredibly well presented tutorial on this topic - thanks for the detailed explanation and study of each of the approaches to solving the issue.
I'm not much into manufacturing but I remember that there are 2 reasons for chatter: static instability or forced vibrations. The second one being more straghtforward as the chatter occurs at the frecuency of the force being applied to the tool, varying cut speed solves the problem in most cases. For the instability, it is mostly caused by the cut depth being increased and decreased due to the flexibility of the tool, holding mechanism... This last one could be solved by changing the shape of the cuting tool (u can see it in interior hole cutting tools), or how the tool is fixed. As many people suggested, even untightening a bolt, intermediate material in the holder or changing the lenght by grabing the tool in a different point can solve this problem also.
All in all, nice illustrative video showing the chattering and a way to solve it, as you said, many times avoided to propose a consistent solution about.
The solder around a small boring bar and the annealed copper strip under the tool bit are excellent ideas. I have used lead strip on larger boring bars in the past with some success. I will try the solder trick next time I use the small boring tools. Well presented sir. One of teethings I have done on the past is vary the spindle speed if you have a variable speed arrangement on your machine to work around those pesky resonance frequencies. While It can be a bit of a pain in the backside, If nothing else it can get you through the job. Cheers
Variable speed spindles works well in industry. Normally pickups kick in that function immediately. Unfortunately the home workshop is less likely to have that function. Manual feed does something very similar. I couldn't get chatter when manually feeding because I would autocorrect before I could stop myself 😂 Thanks for the comment.
I keep a chunk of oil clay on my lathe specifically as a universal vibration dampener. It instantly takes care of most chatter caused by significant overhangs. It even works well on long, thin parts between centers.
Thanks for the hints. I spent a lot of time in a machine shop as a welder and noticed the copper underneath the tool but never thought anythinv other than it being a shim. Now I know the purpose for when I get my old leblond up and running again. 👍
Good video. Let me tell you about my secret trick for dampening high frequencies: tighten the tool holder screws less than usual. And if you have multiple screws, let's say 3 screws holding your tool, actually use only 2, the first one and the last one. Don't even touch the tool with the middle one. Tighten the first front screw normally, but not strong. The back screw, tighten barely. Just touching and applying the slightest pressure.
I've been using those tricks to bore impossible bores, mostly on CNC lathes that tend to have super high harmonics because everything is so tight and rigid compared to manual machines
Huh, that’s really fascinating. I never would have thought of it but it makes sense, (OTOH, I just have a home-grade 12x36, so too much stiffness probably isn’t likely the problem it is with a high-end CNC :-)
I'll try that. 👍
Ahhhh to get soaked with coolant trying to keep your arm and wrench out of the danger zone while a CNC lathe is taking a deep pass making sure you don't accidentally loosen ALL of the clamp screws... the days before new machines got all serious about "safety features" 😆 I tune my boring bars the same way when I'm setting up just to get ahead of any chatter. You can get some pretty serious overhang like that
انت عبقري بالفعل كلامك فيزيائي وانا اوافقك.
For the first time the right explanation of "chatter". The problem has an analogy with audio. Resonant Frequency (and it's harmonics), Damping, (external and internal) , Stiffnes, Mass, etc,etc, are items wich are the basic items when talking about acoustics and UNWANTED Frequencies (especially Loudspeaker Engineering). And chatter is an unwanted mechanical frequency. These unwanted frequencies can be mastered with the solutions mentioned in the video. The solutions are the same for audio . All these solutions (and more) are also known by audio professionals such as audioengineers and speaker builders .
Several things to try that have been alluded to by other commenters. First, try speeding up the spindle rpm to try to get away from the natural frequency of the work. Slowing down a notch on the rpm often doesn't get you far enough away from the natural frequency, but is worth a try.
Second. If your lathe is capable of handling the loads, try using the recommended speeds and feeds in the Machinist Handbook (or similar reference) for production work. Sometimes on long unsupported work an increased feed rate will load the work so it won't chatter. The trick is to finish with a heavy cut to size if the coarse, but smooth finish, is acceptable. If you try to end with a light cut it will vibrate like all get out.
The discussion in the video about the cutting tool profile is the reason I use cemented carbide tools instead of insert tooling. I can grind the cemented carbide to a sharp corner profile whereas, unless you have just the right insert, the insert will present too much cutting edge to the work for a small hobby lathe. Additionally, American made cemented carbide tools are just a couple of dollars apiece and last for years in the home shop.
Cheers from NC/USA
I have had some luck with the brazed carbide tools, but I realized to get the more pointy tip required, on a small lathe, you could take, say, a left- handed tool & lay it on its side, and then you have less carbide to grind away to get the sharp tip for a right handed tool - and if you grind some top relief, you have the whole width of the carbide tablet for resharpening. Bonus if the carbide was sloped away from the cutting side because then you get some side relief when you tip it on its side, without grinding away a lot of carbide - or can mill the angle on the bottom of the tool shank.
Using a coarse green wheel to rough things out with these, & the imported ebay brown diamond wheels seem to work pretty well, for the price..
Also experimenting with re-shaping used carbide inserts for this - I am suspicious that they are often a better grade of carbide..
Great video, was just having some disappointment with some chatter last night on my 10" Logan.. probably pushing it too hard.. although I was getting a really nice finish with a carbide shear tool with a fine feed rate, once I was done roughing (see Mr Pete, & other videos..)
For inserts equivalent of "sharp" cemented carbide, you can use 5 things to your advantage in the world of inserts. 1: prefer a small nose radius (0,2 to 0.4mm even for roughing, they are stronger than they used to be). 2: use CVD coated inserts instead of PVD coated, because the coating is less thick, which keeps the sharpness of the cutting edge. 3: use a positive tool geometry rather than negative, which decreases cutting pressure. 4: some inserts are ground after being coated to recreate a sharp edge, as well asuncoated inserts for finishing, and choose a light-cutting chipbreaker design. 5: rather than the common 5 degree rake angle, position your tool to have a neutral 0 degree rake, in this manner the force is directed 100% towards the spindle and radially, rather than towards/away from the workpiece, and this helps a lot
Do you mean brazed carbide tools?
Cemented carbide is what inserts & the brazed-on carbide pieces on brazed carbide tools are made of.
@@nutgone100 You saved me saying it. I get triggered by the incorrect use of the term... Because a manager I had at one time used to refer to "Brazed on carbide" tooling as cemented carbide, and reacted badly, when, tired of hearing it said, I corrected him... He didn't like my criticism of his trigonometry, either...
@@windrk_6754 and if you grind some top relief, you have... unnecessarily removed the nicely diamond lapped surface the manufacturer provided... And reduced the thickness of the carbide tip, and caused it to generate more heat in use. Carbide tool sharpening was a five stage progressive process when I learned it... Roughing to lapping...
When you buy brazed on carbides, use them with the top/back/compound rake they came with. Just grind the front and side clearances as required. grind them as soon as you become aware they're dulling, so you needn't do to much grinding at any one time. Grinding front and side means you need only adjust the tool height a little, if anything, when you remount the tool. Grinding sooner, rather than later saves you the discomfort of handling a hot tool. Grinding the steel shank below the carbide with a coarse aluminium oxide wheel before grinding the carbide with a green grit silicon carbide wheel makes life easier, too, the silicon carbide not being called upon to remove material it wasn't constructed to...
And... Don't grind chipbreaker grooves into the brazed on carbide tip. Yes, it does work, to an extent, but it weakens the tips, and reduces their life expectancy... Right grade, right shape, right rake, grind little and often, and not on the top, if it's avoidable. If a big flake of material's chipped off the top, you may have to grind the top, but it's a pain... C60MV was a good carbide roughing wheel, from memory, C120MV before diamond lapping (with a close dress) Open dress it for roughing if you haven't a coarser wheel... The bigger the grinding wheel the better, a small wheel tends to leave a "hollow" below the cutting edge. Grinding on the side of a straight wheel's frowned upon, and dressing it's a bugger anyway. Have, but seldom, used cup wheels for carbides. Not often found in general shops...
Thank You SO MUCH for this clear and very informative video. I use a Chinese Sieg lathe normally and have just got boss of that but on my Peatol / Taig Micro lathe I was getting chatter marks even though the tool I had ground seemed to cut well. Then I tried t strip of copper cut from a pipe and annealed and placed under the tool. Using all the same speeds and feeds and it was like a different machine, suddenly everything has come right Brilliant!
The chatter can also be from work hardening the surface. I had a heck of a time cutting 4140 on my small craftsman lathe which is by no means a real rigid lathe. The cut was mush better when I slowed the spindle speed as slow as possible and took slightly deeper cuts.
Great info, it'll be of much use to me I'm sure. One thing I'll add that can sometimes help but isn't actually possible on a lot of machines is to bump the speed up and down. My old raglan with its variable speed drive held me out sometimes but I'm sure the tips in this vid will do a better job, thanks!
Thank you Luker, a very informative and well presented tutorial with practical demonstration backed by theory.
I was a manual lathe operator for about 15 years and turned down a lot of long pieces even longer than what was shown here. One time, a man said to add some rubber bands around the piece being turned and I was amazed that the chatter went away.
It's damping, not dampening. Dampening is making something wet. Damping is dissipating vibrational energy.
Thanks for saying what I wanted to say. That is one of my pet peeves for sure and right up there with “irregardless”.
I think we all grasp the meaning of what the guy is trying to say without the need for pedantics , this is a lathe tutorial not a grammar lesson , life is too short . 😬
@@deancooper7952 and THAT attitude is how you end up with an entire generation unable to express themselves accurately, making for misunderstandings, inefficient communication in the work place, etc. Sit down.
Nobody needs a lecture from you. We get what he meant. @@railgap
@@deancooper7952,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, grammer is as vital as the accuracy of math,,,,,,,,,,,,,,,,,you must be a dem,,,,,,,,go vote for sleepy joes people
Totally fascinating, and wonderful tip about using solder wire on boring bars,mthanks!
Thank you for this video it was very informative. I Am brand new to the world of Machining so any helpful information like this is very much appreciated.
Look up model engineering techniques, this is where you find the best information for the home workshop. Very rewarding hobby! Enjoy, and thanks for the comment...
Never heard of the copper under the tool trick. Easy to try. Will be giving it a go 👍
How many of have ever do this:
Take something like suger size chips and place a few on the tool tip, the tool holder, the toolpost,the lathe Bed, the lathe headstock, and then cut/turn(Notice Depth/Speed)...and watch where these particles moves/vibrates......I would say that a very practical way to zoom in on where to start.-?
The cutting tool geometry is interesting above everything else, and the thing about Above Centre, On Centre, below Centre+Tool flex, . Now if you slightly above centre, if the tooltip goes into the work, the something has to give bend /flex or just cut.
So if you change the tooltip geometry, it may just cut well with no vibration frequency generated, or you shift the frequency/vibration away from the tooltip into the work, which may or may not absorb it........
Don't forget about the natural frequency of the work you are turning. It is loading and unloading and deflecting too. Also the section is reducing in diameter changing its stiffness. The RPM is also a forcing factor....pulsing the RPM while cutting could keep chatter from forming and repeating.... better solve for the eigenvalues!😂
Nice video, what also works is to rotate your tool, and of course run your lathe ccw, your tips are for a craftmanship basic knowledge. At least when I started at a lath 35 years ago a old craftsmanship trained me al this tricks.
Very useful and insightful video.
To add, the same principle applies to the work piece, less stick out from the chuck for unsupported material and if longer cuts are needed to make sure the part is supported on a live center and to add a steady if possible.
What I have also experienced while parting specifically was that the length of material on the back of the chuck(sticking out into the spindle) will also cause chatter if it is left too long. This means you want to not only part of as close to the chuck as possible, but at the same time, use a short as possible piece of material.
In my case I was parting 22mm material while making 15mm long parts.
If I rough cut my lengths of stock more than about 250mm on the saw, I suddenly had issues with chatter while parting.
This would gradually go away as I'm removing new parts from the stock and as it started to get shorter. Between 250mm and 270mm was the sweetspot, anything longer and the chatter will appear.
Naturally this will all be related to the thickness of the material which will be stiffer the thicker the stock is meaning that more stick out is possible.
Perfect example with proving of chatter point according to theory portion also.🎉
Very excellent approach and knowledge - i am pleased you created the video. You often refer to damping - which in principle is a resistance force added to the vibration to reduce its amplitude (and consequently reduce frequency as a secondary effect.) Most of the examples you gave change the driving frequency (pointed tool) or the natural frequency of the assembly. For instance the lead solder likely adds a secondary natural frequency whilst the copper likely reduces the natural frequency. I look forward to seeing more of your videos
damping is about turning oscillating energy into heat, out of the oscillating mechanism - which is what chatter is - an oscillating tool/work interaction.
Obi1 on the lathe. Many thanks and hats off. If I had an award, you'd get it. MVYTuber
It's rare that I have encountered chatter, and on a regular lathe, I first check the length of the tool bit, reducing the overhang as much as possible. If there is still chatter, slow the RPM down. Then reshape and sharpen the cutting edge. Make sure that the piece is mounted securely so it can't move about while under load. Make sure that the gibs aren't too loose. Use some lubricant. Loose headstock bearings can create chatter.
On a brake drum and rotor lathe, use the dampers that came with it to get rid of harmonics and the chatter that ensues. Small drums and rotors don't get much chatter generally speaking, but bigger ones do more often. The design of some brake rotors chatter more than others. If you still get chatter with cast iron, change out the tool tips.
What an awesome video! Will have to try the anti chatter wire. I do all my work with hand feed...I like to feel the feedback of the machine.
This is the type of content i like to watch, i wish you could do more machining videos
So interesting! Lots of detail in a surprisingly short time. Well worth reading the comments too. Thank you
Very interesting, nice video, animations and explanation. From my experience, we have bent/broken Sandvik antivibration boring bars, these things kept screaming and breaking inserts no matter what but we urgently needed them to rough out big stainless cylinders. After some time trying, I just took a single massive cut (3.5mm) on low cutting speed and bit higher feed and it worked. The insert life was not awesome but lasted 20-25 minutes in-cut and managed to survive one part. The finish was horrible but it was just a roughing operation. I tried the same with external tools and it worked too few times. Just take bigger DOC, so the tool bends down and doesn't spring back. Just be careful not to break it into two.
From my experience on small lathes I have found that varying the feed and speed can eliminate most chatter but it needs to be done continuously. Once you settle on a particular feed/speed then it's not long before the sympathetic inherent harmonic vibration creeps in. I have in desperation twiddled the speed control on the VFD back and forth to kill any build up of vibration especially when cutting hard bronze with a fine cut. The tool attempts to skate on the surface instead of cutting and this causes the tool pressure to change and then it will dig in and the whole cyclic performance repeats at an annoying frequency. A rigid and narrow cutting surface along with a sharp edge and a suitable speed and feed will get you through most situations. Tubes can be stuffed with cloth for outside turning and for inside turning your damping wire is a good addition to the long thin boring bar. I find that turning stainless steel tubes to be the most difficult and I will try your dampening wire along with weights attached to the outside of the tube with Jubilee clips. Thanks for making this video but I think you have a few more tips to convey on this subject - the bane of every machine turner!
Thank You, I'm headed out to try it. I still use the rocker tool post on my Atlas lathe. I do have a chatter problem 😇🙏
Someone suggested getting away from the resonant frequency by increasing rpm. In fact, You want the rotating frequency (revs per second) to be an integer multiple or division of the resonant frequency (herz). This way the tool 'bites' into the workpiece at the same angle as it rotates. So either decrease of increase rpm untill you find the sweet spot. There are many.
If I get chatter I change the speed of feed or the speed of rotation or cutting tip design or distance cutting tip is out and sometimes rest a drift punch on the cutting tip for dampening. The last thing I want to do is not use auto feed. It's bad enough that I have to do angle cuts manually as my Chinese lathe doesn't have that feature. I do really like that lead solder wrap. Good idea!
Try turning towards the tailstock on difficult to machine materials..... This keeps loading up the tailstock centre.
You can also use a stack of o-rings on boring bars to add dampening.
This was always our first approach too! Simple method and most times very effective. We had a large crate with thousands of different O-rings for this. And a whole bunch of short steel tubes that could be "rolled/clamped" over the O-rings. In some cases this helped solving impossible cases.
Sometimes I let a wrench or dead blow hammer ride on the turning part to damp the chatter. That is usually my first move because it doesn't involve stopping.
Interesting idea, how do you stop it from falling off when you start?
@@Lukers_tinkering No I am holding it by hand and adjusting the location to find the nodes. Just letting it rub so the mass changes the frequency.
Ah... that'll work! Sounds like you an old hand with machining, I would be hesitant to suggest this to a novice. This is for the advanced class... @@billshiff2060
@@Lukers_tinkering Yeah it can be finicky finding the antinode of both the part and the wrench/hammer and make them cancel out. Just stay away from the chuck jaws and don't get between the rotating part and the tool post.
thank you for a wonderful video, cheers from Florida, USA...Paul
Another way to visualize the damping effect on a vibration system is when you put your hand on the system and it eases.
Obviously on something safe, like washing machine or a small motor.
Since you cant put your hands on the tool, a wire of such sorts is a viable solution.
Interesting to think are there tool holders in the market incorporating this method? Like adding springs and pads to soften vibration?
I love learning new stuff that makes sense. Thanks👍
It's all about tool pressure/cutting force and harmonics. Using a smaller nose radius almost always helps. Using a more negative lead angle with a positive rake angle is the way to go as it takes less pressure off the part and into the center of the cutting tool. Sandvik has good literature on this as well as a FREE course on their website.
The spring you put on it slightly damps the vibration too.
On long shafts try turning against the tailstock, make sure it’s well,clamped.
thanks, I like how show the book, that helped me because I always thought frequency of materials seemed to play into the problem.
The wide profile tip allows the chatter to build up as the tool goes back over its chatter from previous rotations of the part. A sharper profile and faster feed both reduce this problem. The frequency of your chatter seems too low for tool chatter. I think its the workpiece flexing. Just keep in mind everything involved in the operation from the workpiece to the tool and the lathe has some flex and can chatter especially if natural frequencies match.
What a great subject! Your video really made me think about this.
You talked about changing the natural frequency of the tool and introducing dampening. Another place to look is where the chatter is created: the angular distance between the cutting edge digging in and getting released. Increasing the RPM causes the angular distance to be covered in a shorter time, increasing the frequency. Increasing the depth of cut will lengthen the angular distance to the release point, lengthening the time and lowering the frequency. Of course, the material plays a role as well in how deep the tool can dig in (harder material will increase the frequency) and the force at which the material releases the cutting edge (softer material will also increase the frequency).
Also, we need to consider the natural frequency and vibration amplitude of the workpiece. As you say, it’s a complex mechanical system with many degrees of freedom…
True, but the idea of increasing the feed or depth of cut is to decrease the spring back thus effectively reducing the chatter. Essentially you keeping the tool down, albeit by fractions... You also adding a certain amount of dampening and this has to do with the size of the chips and the localised deformation at the cutting edge...
Agree completely. You’re focused on reducing amplitude while I was thinking more about avoiding resonance. But on the lathe, the frequency of the workpiece changes constantly, so my approach is probably more valid for the mill
On my 9 inch south bend I eliminated the chatter by using a 3 phase motor and an inverter from Amazon. Turns out the single phase motor which hummed like a washing machine was making vibrations in the whole lathe. Also by using the inverter It's possible to vary the rpms with the turn of a knob.
I only get chatter when facing on my chinese lathe. Shortening the tool overhang and making sure all slides are free from shake sometomes gives a fair cut but some of the problem I think comes from the speed control that pulses the drive motor and adds different vibration characteristics. I have used really old worn out lathes with smooth drive belts and obtained very neat and smooth facing despite all the wear on the machines.
Great stuff, but dampening is when you wet something down. Damping is when you reduce vibrations...
Hi sir,
Can you please make a video to guide you in performing finite element analysis simulation on boring tool when machining, I really want to learn from you, thank you for making this video.
Same principle to eliminate anvil ring by wrapping chain, setting on a bed of silicone, and/or sticking magnets to them. It changes the frequency.
Very clear explanation.
Nice to not hear a U. S. accent.
Thank you.
Great video. Just one quibble though. Dampening is making something wet. Damping is what a shock absorber - and your copper - does.
True... my bad, got to love autocorrect!
The only way i really got away from chatter is changing the cutting geometry by stop thinking as it digging Into the part but running towards the head stock as you cut.. i paid too much attention to sharpening the edge towards the part. When i started grinding the tool so it cut towards the headstock i helped the chatter a lot even with tiny cuts i now get no chatter.
3:25 What a revelation - I had never learned about tool geometry making such a difference.
Thanks from Canada.........I found this very informative .
Hi Luker great info as a newbee it will be of immense help.
Look up model engineering techniques, this is where you find the best information for the home workshop. Very rewarding hobby! Enjoy, and thanks for the comment...
Why is nobody mentioning the fact the the tool is WAY stiffer than the workpiece. That long, thin, mild steel workpiece being worked right in the middle is certainly deflecting FAR more than the short, fat, really hard tool. The 'anti chatter wire' is a red herring that has no business in this video. I'm very interested in the ideas that the shape of the tool and the aspect of the work matter a lot, but the former was clouded and the latter ignored in this video.
Got a sub and a like for this vid alone, sir !
I made a solid toolpost for the cross slide (no compound ) and this made a big difference in the rigidity of my small lathe...
I also dislike carbide-insert tooling on small lathes as the large(ish) nose radius tends to result in chatter, the comparatively blunt edge carbides usually have (positive rake) doesn't help matters either. 🙄
😎👍☘️🍺
They make lead tape for altering the swing weight of golf clubs I wonder how well that would work especially on a long stickout boring bar.
I’m a time served welder of 50+ years and I remember once working in a workshop that had welding, fabrication and machining equipment and one of the turners in the machine shop was profoundly deaf and he worked by using the feeling of the vibration of his machine to know the finish that his machine was producing, the only problem was that he would have his lathe screaming high pitched and when anyone pulled him up about it he’s would hold his hands up and apologise only to turn around pissing himself and pop out another bang on job 😂
Very nice and detailed video!
Great insights! The length of the stick out changed the frequency.
I had flashbacks to Dr. Wells lecturing about vibrations, except i wish you had taught that class. Dr. Wells did a terrible job of showing how systems vibrate and how to detect the frequency and dampening. There was always a "c" factor, but did he ever explain how you find that? Or, how to predictably change it?
I cut a lot of stainless heavy wall tubes. 24-28” length. I was having issues of poor finish in the middle and used an indicator to check if the center of the part was whipping a bit. It was so I slowed the part down but then found the lack of tool pressure was giving a poor finish not chatter but poor surface finish, research revealed the stainless likes some cutting pressure. So I tried one with more shear better but not great. I added the steady rest in the center which improved the cut but matching the finish in the center is difficult.any suggestions would help.
That's a very specific condition, and I hope this isn't a commercial venture... that length you should be using a traveling steady. Check tool height along whole length of cut. Your depth of cut has to be more than the tip radius assuming you are using tip tools, and the chip breaker is very specific for stainless. What can also help is to plug the tube with wood or soft plastic, basically you machine the plug to a easy fit, cut the middle 45 deg and machine a bolt hold. If you tighten the two pieces it will plug the tube snug. This will add massive dampening and should solve your problem!
Thanks for a well presented video.
Those are some really nice tricks to try out 😁👍
What would you recommend if modifying the tool holder and tool bits solve the problem but the vibrations also appears in the shaft you are machining? Base on my experience when you install the follower rest there is a tendency to solve the problem but upon removing the follower rest I somehow notice a deflection or bending of the shaft causing it to misalign again specially for small cross sections of diameter in the middle? any comments pls will be helpful. Thanks.
I'm sorry but its very difficult to help without hearing the feedback and checking the setup. From what you wrote the first place I would look is tool height, or bed deflection. It sounds like the tool is climbing. Also check the cutting point and make sure its sharp.
This was an interesting video. I was hoping you would go into the theory a little deeper though. Also, what's the 4th mode of vibration of the tool? I can only think of three.
Yep, when I was in college I didn’t like formulating differential equations let alone solving them.
The second derivative of position with respect to time is acceleration. The third derivative of position with respect to time is called 'jerk'. I heard the hubble telescope had specifications up to the seventh derivative.
Now I feel like now I know why!
It would have been better if you at first changed the tool geometry then added the ant chatter wire. That surely would have been more accurate way of showing each method. We used to you magnets or simple elastic bands depending on access needed for the tool. We were also taught that you keep the tool at its shortest tool overhang for each tool needed. You could also change speeds and feed rates to eliminate the chatter.
Use a travelling steady!
It all makes perfect sense.
Great idea! I will try it out!!
Very interesting. Nice video. Dankbaar
@@RustyInventions-wz6ir 👍 hoop dit help!
@@Lukers_tinkering kan nie kla nie, hoop dit gaan goed daar ook.
Very informative. Thank you.
Excellent video…thank you..
Go to Open Source Machine Tools and learn how to use a lathe. Also overseas lathes need to be completely disassembled, cleaned, lubed, reassembled and then finally adjusted properly. Then come the mods to almost eliminate deflection. My G0752 never chatters unless Im being scared with the parting tool and using too slow of a feed rate. As soon as I grow a set and speed up the parting tool the chatter disappears. 99.9% of deflection on overseas lathes comes from operator error.
Make chips that dont need dips!
Forge On!!!
Great Instructional Video !! 🤗
Lovely South African acsent!!. Learnt a lot.
USE a STEADYREST ! Or FOLLOWER REST , Keep the cutting tool SHARP , Use Cutting oil and Feed the Tool Slowly . It all depends on DIAMETER , Type of material your Turning , and Many other Factors as well .
I was dying laughing at "oh she is unhappy... Oh she is unhappy". As your voice became louder. Hilarious
Why don't we use a semi-circular choke? The contacts are often copper and may have been made for this purpose
Hola, saludos desde Argentina, en herramientas de interior hago que sean mas largas en la parte de atrás, y en ese saliente le pongo un buje de bronce, y solucioné el problema de la vibración
Im hashem from yemen , isee very well thank u friend❤
If you are machining the OD of a hollow job and it starts singing , you stuff the ID with a rag and the harmonics stop
Parabéns pela Aula !
I'd like to see you film that chatter in real time with a million frame per second v2511 Phantom camera.
I'll check my Poweball ticket in the morning and let you know if you're going to be able to do that.
😁
I have just discovered your channel. This video is very interesting. I see you are also from ZA.
@@improviseddiy yep where diy is the only way to get things done properly 🙃
@@Lukers_tinkering Where in Gauteng are you based?
Second pass you hand fed. First you power fed.?? Thanks for your info.