Parting Blade Grind- Quick Tip
ฝัง
- เผยแพร่เมื่อ 12 ก.ย. 2024
- A different, and very effective grind for your parting blade. The results are amazing! I couldn't find any specific information on angles or depths, so this video is only enough to get you started.
Filmed 15 July 2015
with an iPhone
Edit with Serif MoviePlus
Slow the machine down, reduce your overhang and decrease the rake underneath the cutting edge and it will give you nice silver coloured swirls that come off with a scything sound. The vee in the top is a grind I have used for as long time now and like you I am in love with it. Another thing is to inverthe tool andrun the machine in reverse, that way the waste material falls out with gravity instead of trying to get stuck in the groove. Last thing but of equal importance is to use OIL, the thicker the better and trust me you will think you bought a new lathe when youcombine ALL those steps.
This all works just like Billy Says it does.. But, the real reason you want to Run the tool inverted, and in Reverse is that, when the tool bites in, it pushes away from the work, rather than pulling into the work..
The swarf follows the V shape in the tool, causing it to be narrower than the groove it's coming out of, and this greatly reduces the pressure on the blade in deeper cuts. Nice video.
I in 46 years of machining have never seen this grind on a parting blade, but it does work! Thanks!
Incredible! I always had trouble parting off with a small Bust Bee lathe. It would chatter like crazy and often snap off the blade. I just did what you did. I parted a 1.5" aluminum bar in no time. Thank you!
Amazing to see the curl getting thicker and "Slowly" coming out the tool.... It's like it gets hot enough to allow the smaller chips to weld themselves together... Pierre
was super glad to learn this. tried it on a 1 3/8 " piece of 12 L 4 steel and worked great, was useing cuting fluid, . then it would not cut on the second piece. sure worked good the first time. more research needed .
Interesting. My guess is either it chipped, or it moved off the center line, but good to hear to worked for you! :) It's really been a time saver for me!
Thanks man! Watched your video 5 minutes ago and now I'm doing the cutoff !
Nice! I'm going to try that on my watch maker lathe today. So it looks like you are basically doubling the cutting surface area on the tool in a stronger cutting angle. That is amazing!!!
Blown away is a accurate description.
Thanks for sharing that. Gonna try this tomorrow.
Like anything with tools it's hard to discover the best way on your own when others have already figured it out. There are some darn good videos on youtube to learn from.
The rate of spin of the part and the chip coming off of it slower makes me think your not cutting it off as much as rubbing it off...
In other words its crushing together into the v , maybe this reduces chatter but its putting a lot of stress on the part tool and lathe..not that it wont handle it just that i kinda would like it to cut metal off not drag it off. as someone mentioned if the cutting edge as ground so it had an angle up into the part it might cut smoother?
I will have to try this out though ...cheers!
Yeah, I can see where you're coming from on this. I did try it on my 20 year old Harrison M300 and the results were closer, i.e. not a great difference between both versions. I put this down to several things. 1. My lathe is in good condition, beds, slides, bearings etc. 2. I set my tool height with a height gauge, as I do when checking / setting adjustable holders. I think perfect centre height is the key, did you do this? 3. You used lube on the 2nd cut & not on the first can I ask why as this gives bias to the results. 4. I lock the carriage when parting, did you?
Additionally I found the tool life greatly reduced on the modified tool by a huge factor. Have you considered replaceable tip types? They are very good and if set correctly don't overheat if speeds are right and so on.
Still a good video though, food for thought.
Steve from Cuxton, England
The groove on the top causes the chip to curve making it thinner than the groove ,it is standard on most carbide parting tips and reduces cutting forces and heat.
First time I've seen that! Cool. Will try it myself. Thanks for keeping your eyes open for all of us.
Jim Milne No problem Jim!
Interesting approach, I have massive parting problems. I might give this a try as well
Interesting, I have some carbide inserts that have a twin v w profile very much as you have attempted Works fine everything I have parted off, so available commercially for various materials, a must have.
Adding this to my favorite playlist. Great little tip.
eviltwinx Pun intended?
It changes the operation into multiple smaller load cycles, each happening in turn, then going back to go. Kind of like the tooth set in a saw blade, where teeth alternate biting the sides of the kerf. The "chip" does that because those multiple rapid cuts feed into what is essentially a common chip breaker, thereby "balancing the break forces to zero", and thus an unending stack of connected wedges alternating bias direction
Always something to learn. I'm just glad I don't 'know it all' like some folks. Seems like that'd be a lonely life all by yourself looking down on everybody. BLESSINGS, Yall!
Nice!
A chip breaker for slot cuts basically!
Whered you day you learned this?
great tip on the tip, looking forward to trying it Matthew :)
That chatter was bad but made it sound like it was running diesel motor
Marvellous, i have much trouble parting off steel i will try that next time-thanks.
Thanks for sharing..I'll have to give this a shot as parting on my lathe is a nightmare!
Saw this one time before...it has worked well...
Yep, there's a good reason why every single carbide parting insert on the planet looks like that...
Definitely going to try this ... thanks
That has got to be the WORST Parting demonstration I have seen, it is NOT cutting at all , the notch may be fine for soft or brittle materials like Aluminium alloy and brass/bronze .
in effect the notch changes the vertical position of the cutting edge and since the blade is not at centre and is angled down your cutting at the outer corner's and literally rubbing or scraping the material away in the centre hence the bluing (Bloody Hot) . your speed is IMHO too fast and angles all wrong for Steel, the top of the blade can be slight negative rake and about 2 degrees relief in the ground face UNDER the dead square ground cutting edge which should always be perpendicular to the centre of rotation. .
Trolls are thick today.
This is what you're doing wrong.
1. Job is held out too far from the jaws of the Chuck.
2. Speed (rpm) is too high for that material and hss parting off tool.
3. Incorrect clearance on the parting off tool.
And 4 I'm almost certain that the parting off tool is burnt after that one part off process.
LOL!!!
Thanks........ I'll have to give that a try..
grinding the notch you lower the cutting hight so it will make a curly chip
Great idea, thanks for sharing.
Have to like that. That was cool and Iam going to be trying that out. Thanks.
You should part off as close to the chuck as possible.
Great tip Matt, pun intended. its almost like a form tool maybe either way I like it
Billy...
Billy T Thanks Billy!
That works great, thank you for the tip!
Great tip, thanks for sharing I got a lot farther after I made the modification.
Thanks for the tip !! worked great
Lathe sounds like you have rocks in the gearbox.
Nice. It worked for me.
That is a great idea
I'll have to give this a try. I parted some 1 1/4" 1018 on my South Bend 10L the other night and it was not at all happy about it.
I'm confident you'll like it! :) I can actually part on my little Atlas lathe now. I always got frustrated parting with that machine.
I'm impressed you can use one of those dremel cut-off wheels and not have it explode into bits.
craigleemehan I use them frequently and seldom explode one. Maybe it's my sissy grip? ;) lol
Wide Vision Metal Fab I suspect one of us is skilled and other is not. :)
A more modern toolpost would help ,far more support for the parting tool and make the cut as close to the Chuck as possible.
I'm aware of all that, and that's not the point of the video. The point was to demonstrate how big of a difference the type of grind makes.
Amazing!!!!!!!!!
I’ve used that kind of grind for years. It does work but you need to check your blade profile and remove as much overhang as possible. No way should you have that much vibration and that type of chip. It sounds like your not on center or your rubbing the front face. It made me cringe the whole time you were parting. Keep the grind but experiment on your profile and overall setup. There is definitely something wrong. Thanks for sharing.
this could work really well but the way you grind it the cutting edge is negativeif you do the same with a positive angle it would go a lot better i think
works Great with the positive angle !!!!
To Easy. I'll be sure to try this.
Interesting. I think on a normal tool they would call it a chip breaker but clearly that is not what it is in this application. maybe we would call it 'relief' ?
phooesnax It's odd how little information there is about this. It really is the same principle as a chip breaker in that it causes the chip to curl. Some one also called it a shear grind. Whatever it's called, it works!
I gotta try tha!!
jster1963 Please do and share the results! :)
I like the tip and have an older tool that uses that type blade.
Also, the carbide insert for my cut off tool actually has a notch in the middle.
I guess ur headstock bearing is toasted
Too much noises
Tried it on my Logan 11" lathe.NO SUCESS.
Not sure what to tell you. It works great on both my 20" Rockford and the little Atlas 10D. I still swear by this grind to this day!
Your speed is to high. Lower your speeds for super clean cuts.
Not qualified to teach but he got the rpm right. Not square off center and mainly to much relief 1 deg max
That sure is a the best grind for a standard blade, which by the way was written up in the '60's in ME magazine by a well known and respected author called George Thomas.
There is however a better parting tool, using a more or less standard blade not carbide insert, and if I ever get around to doing a video series i shall show it to the world. Just to whet your appetite, it cannot grab and break unless used by a complete and utter ham fisted moron, or me. Just yesterday i had a grab on some stainless and where with a normal blade it would have broken, the safety kicked in and no harm was done. As you trans-atlantians would I believe say "sweet"
Fear not Don, there are ways and means. Bad parting can be caused by many small things which add up to big trouble. Anything from a worn chuck, to bad bearings, to old fashioned parting tools, lack of lube, through to being a wimp when winding in the cross slide handle can all lead to problems, but there answers to all of them. My tool design for instance alleviates the end result, that of breakage, even if the other faults are still there, as it has a built in safety mechanism (?).
If I could find floor space to put a tripod I could video it for you to copy, but don't hold your breath. I barely have room for my feet let alone a tripod and for once i am being serious.
Chris Stephens I've heard the name George Thomas before. I'll have to do some searching on him. That blade you speak of sounds like a goose neck holder, or is it something entirely different.
Entirely different! I never had any great success with the swan necked style, judging how strong to make the springy bit took too much experimentation..
Chris Stephens Looks a little like the shape of an insert, with the chip breaker. Never seen anything where the notch goes lower than the center line though.... Don't remember last time I had problem with parting, but it's worth the try. ;-)
Chris Stephens I too had seen the George Thomas tip for grinding a vee on the top of a parting tool. A few years ago I purchased a parting tool from ENCO that had a vee groove running the length of the tool. The vee groove was not mentioned in the catalog listing. I had put it aside and only recently tried using it. It does work very well producing a chip that is narrower than the groove it cuts.
The best for fighting cock tari blade
Nothing particularly revolutionary here. Add some lubrication! Any lathe, any tooling, you need mass lubrication.
And I'm glad you already knew how to do the V grind on a parting tool. In my 30 years of operating a lathe, I hadn't come across a V grind, nor have I seen anybody else do it on TH-cam, nor had I seen it in any book. Why do people keep telling me to add lube. I watched this video again just now to make sure, and I used oil. There's oil dripping from the DOM. And FYI, "mass lubrication" is not required. There are videos on TH-cam doing experiments that show lubrication is not required.
@@WideVisionMetalFab umm, well, what's all that bluing on the end of your cutting tip if the coolant was sufficient? I only worked for a couple of months in an engineering manufacturing operation. I was cutting down stainless steel washing machine main shafts on a Russian lathe. We used two different brands of inserts. My boss favoured Sandvik but another brand worked slightly better for me. They don't have a central groove but the tool steel parting tools were traditionally ground this way (L. H. Sparey, "The Amateur's Lathe"). My coolant was always running, not dribbling, over the work. If I remember correctly a good tip might last 200 cuts, maybe 100. It was punishing work and if you didn't react real fast to a failure there was damage to the holder. I recently started getting back into hobby lathe work and used a tool I had purchased, sharpened by the previous owner, like what you made there, on my flimsy Chinese lathe. No coolant setup, just a container and hand work. About 300rpm. Manual feed. I have a chainsaw sharpening setup now with a thin cutting wheel. Hopefully this will help me sharpen my tool. I can't do it with a bench grinder and the angle grinder is not recommended. You might do better, according to your criterion for success, with a lighter feed.
@@nickmansfield1 I'm not using coolant, I'm using oil. Huge difference. And the chip turning blue means the heat is not going into the parting tool, the heat is staying in the chip.
@@WideVisionMetalFab the colour of the tool disagrees with you.
@@nickmansfield1 You are amazingly arrogant. I am so glad you're 2 months of experience trumps my 30 years of experience.