Not too often do I happen to find a new (to me) channel that absolutely amazes me - this is one of those! The care that is clearly put into every shot, camera angle, or animation to carry out some important point is truly impressive!
Remarkable work and great editing. Truly a pleasure to watch. I am curious about the ratio of (1) the time spent planning to (2) the time spent in set up to (3) the time spent cutting.
Thanks! Time spent cutting (per gear) is probably the least. Setting up is really just like tramming a vice, though I may have to do both the hobbing attachment and the mill head. Planning and preparing the blanks etc. can vary wildly though often it's just some simple arithmetic in my head and turning a piece of bar on the lathe.
You should consider adding trepanning to your skill set. The next time you want to cut a round round out of rectangular piece of material it is a lot faster, easier, and leaves a much better surface finish that is concentric to the rest of the part. If you are concerned about the inner part falling out at the end consider leaving a thin web at the end of the cut.
Yes, I sometimes trepan thin material on the lathe, but these plates are 20mm thick (~3/4") which would need a very long thin trepanning tool. I suppose I could cut from both sides though. Any time I want to remove a lot of material quickly my first thought is usually some method of sawing it off.
@@AndysMachines Hi Andy, Thanks for the reply. However, thickness of material does not limit trepanning. It is a great way to remove material. You clearly have the ability to grind trepanning tools. It is a lot like grinding a boring tool that creates shank clearance on both sides of the cut (similar to a hole saw creates a curf wide enough to allow the body of the saw to follow the teeth down the hole). It is not difficult if you understand the geometry and the clearances necessary to manage your chips without hitting the stock on the inside or outside during the cut. I encourage you to look into it. Regarding your comment on sawing off the material, the way you did it in the video created a situation where you had to deal with an interrupted cut on the lathe when you cleaned up the OD of the part. Interrupted cuts are always time consuming and can damage your cutter if you take too deep of a cut or use too high of a rotational speed. If you insist on using your band saw to cut off the square edges of a "round" part then you should consider going to a more narrow blade on your band saw. With a narrow blade you can scroll around the inner part and minimize the stock left for later removal. Once you get used to this you will minimize (or possibly eliminate) the interrupted cut and material removal. Hope you are not offended by my comments but I am just trying to help you. I have over 50 years of prototyping experience and figuring out how to make things. It is hard to go away from old habits (especially in matters of things you have figured out for yourself). However, the faster you get at doing things the more magical things you will create. Any you are a very creative guy. I have a couple of other simple suggestions for you but this is getting petty long so I will make another comment after a while. Cheers, R J
@@rjserra5535 Not offended at all! Thanks for taking the time to write such a long comment and share your knowledge. I have ground trepanning tools in the past by hand from HSS blanks, I usually made them fairly short as that's all I needed and I found making longer ones more time consuming and the tool itself becomes more fragile with length. I don't actually have a bandsaw now (have owned several in the past), so I often go for the quick and dirty 'lop off the corners with a hacksaw and true it up on the lathe.' An irregularly shaped blank does take longer, but I generally use HSS tooling on the lathe so the interrupted cut is not really a problem. Happy to hear any other suggestions!
This was very interesting! I did not know I wanted to see this until you made this video. It is highly awesome you have the knowledge and attention to make your own machines. Love your Terminator build and now I know how you make the tools you have to accomplish this.
Yessssss...........last time I cut some gears was 15 years ago.....still nice to have a dividing head to do all that.......at the time I used a hand ground fly cutter to get the gear cutter profile.......just too many gear profiles and sizes to lay out for a couple of sets of gear cutters......and a hob does the job in one hit after you gash the teeth.
Actually with a powered hobbing spindle you don't even need to gash the gear blank, you only need to do that if 'free hobbing' (and even then you can still end up with the wrong number of teeth!)
An excellent video. About 2 minutes into it I realized I had put everything else aside and was giving it my undivided attention. I'm looking forward to part 2, and have subscribed.
Great video and AndyMachines understand what so many youtubers do not. You did not put background music on. Seems so simple but so many others fail so badly and put on loud stupid/offensive music when they should not.
I think I did get this question from somebody who had a mill with a head that didn't tilt. You can't just tilt the work spindle an additional angle to compensate, since the feed direction must be parallel to the teeth. If you used a large diameter hob with very small teeth and hence a very small helical angle then you could probably get away with not tilting the head (the clearance angle ground on the teeth would be greater than the error, so the teeth would still cut without rubbing)
Thanks! Not really all that heavy, though reaching the limits of some of my tools, particularly the lathe steady rest which really won't go any bigger. Because this is a machine that will be making parts for other machines, I'm trying to make it as accurate as I can so I don't have errors stacking up on top of each other. 🇬🇧
Hello Andy, Amazing videos and thanks for all the effort you put into this. Mechanically I can do about anything but electrically I struggle. Can you give me some part numbers on encoder options. Thanks!
Hello Mr Winky! I enjoy watching your channel! The encoder I used for this project I actually cobbled together from some parts from an unknown make servo motor and a codewheel I made myself. For general use I've always used the HEDS range of encoders made by HP/Agilent, now made by Broadcom I think. I like these since you can buy the read heads and codewheels separately, or the whole thing as one unit. I know a lot of people have replicated this project using the 38S6G5 type encoders which are very cheap on ebay/AliExpress. These can't be directly mounted on the spindle of a milling machine however, you would need to attach a timing pulley or gear to drive it. Directly mounting on the spindle is usually better, but encoders of this type with a large through-bore are specialist items and can be expensive or hard to find. You can always make your own, either how I did, or even from scratch by building the read-head from simple components. (I've said before I'll do a video on encoders one day, how they work and how to make them, I'll get round to it one day!)
@@AndysMachines Great info! Thanks. I may have to use a belt on my mill. It's possible I could mount a disc on the top of the spindle pulley but the encoder would end up inside the step pulley. Doable but the belt would probably be easier. I'll do a video on the build and of course link to your videos. You do a great job on the videos. Thanks!
@@AndysMachines Hello Andy, the specs on these encoders are in Greek (to me). I can make a belt drive or disk type work. I assume the disc can be larger in diameter as long as it has 150 slots (with equal slot width and gap?). Can you suggest a specific part number for either one or both styles? Thanks.
Это просто шикарно !! Золотые руки !!! Начало - нарезание эвольвентного профиля с помощью сегментной фрезы и методом обкатки инструментальной рейкой (прямой зуб).
Wow…. So inspiring. Thanks for taking us along on the ride and show us all that is possible. 👍👍😎👍👍. I NEED to watch more of your content. 😉. This channel should have many more subscribers. I did my part just now - I’ve subscribed and turned the bell on. 😊
Superb machining skills. Superb video too. I feel a bit cheeky for asking, given how good this was, but would be nice if you narrated it - you know - why you made certain choices, what pitfalls you had/avoided etc. But I'll be more than happy just to see it in action on the next one. Thanks for sharing!
Thanks! It's hard to know what level of detail to go into with narration, captions etc. I assume that anybody watching a video like this would already have a fair amount of engineering knowledge. I don't want to make the videos too long by explaining every little thing, people can always ask in the comments if anything's not clear.
Have you ever used a spiral point tap they cut so much nicer than those raspy straight flute taps. What I really would like to know is how it is that you get the spindle and your machine on the same page.
That's called 'free hobbing' and it can work but more often than not you get poor results since when the cutter first contacts the blank it is not at the correct pitch circle diameter and so turns at the wrong speed giving you a different number of teeth to that expected. Sometimes it will sort itself out as the cut progresses, but it's hit and miss.
16:59 song you own a drill press you could've used for this hole making operation? I think that if you had one and you set it on the lowest speed and attached a weight to the plunge handle you could've had it a lot easier.
At the time of filming I didn't actually have a working drill press with a chuck that would hold this hole saw (hex shaft). It won't fit well in a round collet in my mill and the drill chuck I have for the mill is too small. However this corded drill has a lot of torque on low speed and it handled the job better than I was expecting. I could also have done it in the lathe but it would have taken longer to swap the 4-jaw chuck and back.
No, you don't need any advance or a differential such as you might have when milling helical gears on a horizontal milling machine. You only need to tilt the attachment to the helical angle and take the cut as normal, this is because I am using a hob and feeding in line with the teeth.
Obviously you built a CNC hob fixture. Which means you need a hob cutting tool. Something if DYI starting as a ACME threaded with the proper profile for the gear be it 14.5, 20, or some special pressure angle degrees and the other features like root dimensions. Then cut to produce teeth and hardened. Is the hob made or purchased?
I have both hobs I bought and ones I made, I've built up quite a collection over the years. I make them from O1 tool steel (drill rod). Screwcut, then teeth cut in the mill, hardened and tempered. My homemade ones don't have the full relief on the teeth the commercial ones have, but they seem to cut just as well (use plenty of cutting oil). it's useful to be able to make custom hobs for things like splines and toothed pulleys, not just gears.
Just found this channel, you are a really clever engineer, great video, I'll shall be checking out your other videos. One question, I did an engineering apprenticeship 25 years ago and HSS lathe turning tools were old technology then. Is there a reason you still use them? I only do a bit of machining at home now but use only insert tools as HSS is far to slow for me. Again super video!
Thanks! Yes, I do use carbide insert tooling as well, but I've just always used HSS and I like how I can quickly grind any shape tool I need. Also my lathe is only a small bench-top model, it doesn't have the power for really heavy cuts.
AndysMachines thanks for the response and fair comment. HSS still has its place for sure. The hobbing attachment is beautifully made love how you did the scribed degree graduations and etched the numbers. The video has inspired and opened new opportunities through watching it, just shows what you can still do with manual machines at home if your clever enough.
I haven't drawn actual blueprints, there's enough info in the video to be able to reproduce it, it doesn't have to be exactly the same, you can modify the design to suit your own application.
I love your work. But instead of building a spindle from scratch, could I just automate my rotary table using a motor and your controller? Or is there a critical issue I am overlooking?
There's a couple of good reasons not to use a rotary table, the worm reduction is usually 40:1 or 90:1 which is much too high to be practical, though you can disengage the worm and attach a pulley to the back of the spindle. The 2nd reason is that most of these tables aren't designed for continuous rotation, rather for indexing or cutting short arcs and they usually have plain bearings that have a bit of play in them. The play is not much of a problem in normal use and locking the table can eliminate it, but for hobbing gears it does make a difference and will lead to too much material being removed between the teeth especially on gears with less than ~ 20 teeth. But if you can find a rotary table or indexer with good preloaded bearings that you can attach a drive pulley directly to then yes, this can make a very good hobbing attachment.
It's a Sandvik (17:01) but any decent bi-metal type should do it. Keep the speed low, use cutting oil and clear the chips frequently. You can also drill a small hole all the way through in the path of the hole saw and this will let the chips fall through, though I tend not to do this as I find the slug removed by the hole saw very useful (this one actually became a gear for another project!).
Hi, Andy, I have been a long standing admirer of your most excellent efforts and I must have watched this video and part two at least ten times. Being a well seasoned retired pensioner I now find myself with countless hours of time to put some of my misspent skills to a use. One thing I would love to make is a Hobbing Attachment like this. Did you ever publish any drawings for this? If so can I beg, borrow, barter or at the outset buy? Once again I congratulate you on your knowledge and skills and your unselfish way in which you share your your knowledge with the rest of the World. - Thank You.
Thanks Keith for the comment, I didn't actually produce drawings for the attachment as none of the dimensions are critical. You can alter the design to better suit your own needs or make use of whatever materials you have to hand. If you only want to cut spur gears (rather than helicals) then the attachment doesn't need to tilt and can be much simper. All you really need is a shaft rotating between two fixed bearings that you can attach a pulley and stepper motor to.
on 20:59 why are you using z axis descend (with repeated passes like it was a drill) with the mill instead of using the y (or x) axis in that operation? I mean why not directly do like you are then doing at 21:07 sorry for the dumb question, I am learning. Many thanks!
It's often quicker to remove material this way, this part is quite thick and would take several passes to mill sideways, you can plunge cut more aggressively than mill sideways on a thick part. It also reduces uneven wear on the side of the endmill. At 21:07 I am doing a light finishing pass at full depth, note that I am doing this in the climb milling direction which produces a better surface finish.
Is a gear cutter for cutting a rack the same tooth shape as the hob? It seems like perhaps with multiple passes, a rack cutter could cut any number of teeth by turning the gear a bit and moving the cutter the same amount to simulate what the hob is doing.
Yes, a no.1 gear cutter (135 teeth - rack) has the same tooth profile as a hob, though obviously the teeth are not arranged in a helix, and can be used to cut any number of gear teeth by rotating the blank and moving the cutter along the tangent an equal amount (measured at the pitch circle diameter). Using this method you can even cut less than 12 teeth which you can't do even with a number 8 cutter in a normal set. If fact you don't even need a gear cutter to do this, it can be done with a regular tool like an endmill or (better) slitting saw. I have another video explaining this method: th-cam.com/video/eC-OctJoWv4/w-d-xo.html
Andy Real question from ignorance in relation to hacksaw corner removal: you used hacksaw because it’s fastest? Or on a milling machine you are wasting a valuable cutting head? Or??? (no trade background, recently retired and about buy a metal lathe 😊)
Sawing is always fastest, compared to drilling or milling the material away and turning it all to chips. Sawing by hand does take some effort, a bandsaw would be faster, but I don't have one. An angle grinder with a thin cutting disk is another way, but also very messy if you only have a small workspace.
So impressive. Seeing machinists at work has me looking any machined part, however mundane, and thinking about the machine time needed to make it. Or in the days before CNC, what complex jigs or human effort was needed to machine the parts that went into a car, a jet, or any machine
Oh, it was nothing, everything just came naturally, I always thought about how long it took, how much skill and hard work was done to get to where we are in this day and age.
Very nice. Thank you. I usually just skip to the end on Build videos to see the final product, but your editing of the video was so well done that I watched every minute. Question: Instead of cutting the corners off the flat stock with a hacksaw at 5:00, and then later spending a great deal of time removing the rest of the stock in the lathe at 8:50, why not use the rotary table and a small roughing end mill to do the job? I find this work well. Thanks again. Looking forward to part 2
I'm glad you liked the video! Yes, the rotary table is just as good a way of doing this, though personally I only tend to do that when I don't want a full circle (such as when I rounded off the corners of the frame). I roughly knocked the corners off first just so I could centre the part in the 3-jaw on my rotary table (with shims and moving the chuck on the table) to cut the T-slots. I left the final finishing of the faceplate until everything else was welded, bored etc. in case there was any movement.
Your video popped up in a sub-feed from a mini lathe video. Overall great video. Would you try to keep the sound of the machine noises at or below your level of speech loudness? I had to repeatedly adjust the volume. Thank you for sharing this wonderfully inexpensive modification!
You do some really nice work. I’m really impressed. But I’m surprised that you don’t seem to use any machine coolant or even thread cutting compound such as Trefolex. We always used both. The surface finish on threads in steel for instance is greatly affected by tapping dry. Brass is a different story, but we would have been seriously reprimanded for going in without Trefolex. You can imagine the jokes that went along with this rule.
Thanks! As for the coolant, I can see I'm going to have to get a mister and have it visible in every shot, I seem to get this comment a lot! I DO use cutting oil, even flood coolant, but I generally don't show the application of it (though you can see it's there) and I don't use flood coolant in the videos as it would obscure what's going on. Maybe I don't use as much cutting oil as some machinists or reapply it as frequently, and I don't use it for everything, but yes, always when tapping steel.
You do beautiful work. Only thing I would advise is when milling I would blow some air or better some coolant mist to clear the chips. You are forcing your cutter to recut some chips. I think that's kind of hard on it.
Thanks! I generally don't use compressed air on the mill to avoid blowing chips everywhere (I only have a small workshop). I sometimes use a small paintbrush to wipe them away and I usually do a light climb cut for the finishing pass to avoid recutting chips.
@@AndysMachines it does make a mess. I mostly cut stainless in my job. I started getting a lot less damage on my end mill flutes after I started using air to blow chips away from the cut. Air plus some cutting oil mist or flood gives a much better surface finish on stainless when milling a slot. So much difference I couldn't believe it the first time.
I had hope when I saw the "Toolzone indicator" thinking I can afford this hobby, then you brought out the "mitutoyo micrometer"😂. Cool I never seen gears cut like that, thanks for the education, please include more explanation of why you are doing operations and which order for beginners like me. Thanks
Yes, I only have one Mitutoyo and it's 0-25mm but it will actually measure slightly over that, which can be very useful in situations like this. Fortunately I rarely need to measure things bigger than 25mm to 1 micron accuracy.
get yourself a mister. Use the expensive synthetic stuff and use it very sparingly with high air flow about 35 - 40 PSI. It'll improve finishes enormously because it'll blow chips away keeping you from recutting them. It'll also extend tool life and allow you to increase speeds and feeds markedly. For that T slot I'd use a flood. I was concerned about a mister in a small shop. But the synthetic stuff is non toxic and I use so little.
Hello sir, How do you define the Rpm for the blank during hobbing ? I know it have to be synchronise but I dont find any calculs to do it … Thanks for your answer
The blank just turns as the speed of the hob divided by the number of teeth you want to cut in it. Each rotation of the hob cuts one tooth spacing. (For a single-start hob. For multi start hobs you divide by the number of teeth, then divide that number by the number of starts)
I'll cover the actual hobbing in the next video. The calculations are nothing more than a simple division from the milling spindle to the hobbing spindle. There are also a few basic calculations relating to the size of the gear blank vs. no. teeth (and helical angle for helical gears) depth of cut etc. these calculations apply to all gears and there's lots of info online.
Hi! Excellent work! I have a question Is a differential mechanism for helical gears necessary? Like the hobber gear machine have? Thank you for share your work
Thanks! On a traditional universal milling machine where you have a gear train driving the table feed, it's normal to use a differential to advance the gear as it feeds, since the direction of feed is not parallel to the teeth. With the method I use here (I won't claim to have invented it) the 'advance' happens automatically since the gear blank is tilted and the feed direction is parallel to the teeth (not to the axis of rotation of the gear).
I do design things in CAD, though rarely the whole machine, just the parts that I need to calculate some values for, or if I want to play around with the design to help me visualise it. I use Vectric and Turbocad packages. I did try Fusion 360 but didn't like it.
I know everyone can build the attachment anyway one would want BUT at 80 years of age , is there anyway to get hold of your prints that you made yours from?
I didn't actually make any prints for this, I just built it mostly with what materials I had to hand as that was quicker. The only parameter that was important for me was to make the centre height match a tailstock I already had.
Next time you hole saw a hole... scratch the surface with the hole saw, then drill a hole tangent to the scratch mark. This hole allows chips to fall out of the cut and prevents chip packing in your hole saw gullets. You'll cut faster and with less heat giving you years more with your expensive, carbide tipped hole saws
Good tip! I always do this with wood and it cuts much faster (usually 2 holes on opposite sides). With steel I tend pull the saw out frequently to clear the chips and add more cutting oil.
Hi Andy, just found your channel, excellent content. I have downloaded the files for the gear hobber, just a couple of questions if i may, 1: what does one do with the MAIN . asm file? 2: when I use the CMD window as per the instructions I get the following error System wide configuration file is "" avrdude: can't open config file "": Invalid argument avrdude: error reading system wide configuration file "" Any idea what I am doing wrong? By the way spotted the post about COM port number, mine is on COM 5, altering this makes no difference. Hope you can help me I would love to have this facility in my shop. Best Regards Ron Cummings
Hi Ron, The .asm file is the assembler file that the .hex file is compiled from. You don't actually need it, but I included it as some people might like it for reference, or to edit it if anybody wants to modify the code. 2. It sounds like avrdude can't find it's configuration file (avrdude.conf), either because it doesn't exist, or maybe because it's not been told it's name? Have you just installed the arduino software? If so you might need to use the IDE itself to upload a file to the board (eg. with 'hello world' or any example project). This might initialise the configuration, but I'm really not an expert on arduinos, maybe somebody else reading this might know the answer? Yes, you will need to set the -PCOM command to suit if you are not using COM 6, I neglected to mention this in the video, but I have since updated the 'how to' text file.
just beautiful dood. well over 20 minutes and the best i will spend today!! i love the lathe tool that did much of the turning, it seems to be have two sets of super imposed geometry? also i am curious, at 5:25 you use a dti fixed to the mill with the finger on the bore of the work, which you then spin and show the clock not moving (so nice!), are you checking conecntricity of said bore or are you checking the work is centred under the spindle of the mill? if the later then please can you explain your procedure here? fair play with the hack and hole saws...i know those jobs! cheers again and look forward very much to watching the rest.
Thanks! Not sure which lathe cutter you mean, but with the dti I'm centring the workpiece on the rotary table by using shims on the jaws of the 3-jaw chuck and also tapping the chuck around on the table (the workpiece is a rough octagon at this point). This is so I can cut the t-slots accurately, it's not critical to have them centred but I wanted to do a good job of it.
Generally yes, but not always. Also when videoing I sometimes do things differently and avoid things like flood coolant which make it harder to see what's happening.
Cutting oil is for the purpose of preventing the chip from welding itself to the cutting tool or the work. It is an absolute necessity with certain materials and processes. It can be of little value in other cases. For example, center drilling 304 or 316 stainless always requires cutting oil. Threading pipe, especially stainless pipe always requires cutting oil. Further, not just any oil. Sulfur based cutting oil is the minimum. Otherwise, you can count on breaking your dies. Even deathly expensive pipe dies made for stainless will chip without the proper cutting oil. I know this from first hand experience, not just from a book. To restate, don't try to use Tap Magic to thread stainless pipe.
That's called 'free hobbing'. It can work but you need to be very exact with the setup or you often end up with one more or less teeth than you want. It helps to gash the blank first with the right number of shallow cuts to give the hob somewhere to start.
@@AndysMachines hi thanks for the reply. Will it produce accurate teeth? I did cut a nylon blank but i feel the teeth are skinny compared to the hob, do u know why?
It may not be as accurate, the problem is that the hob is driving the blank like a wormwheel so if the hob is not cutting at full depth it will want to turn it at the wrong speed. It's better to feed the hob in axially already at full depth, rather than feed into the blank radially. Also free hobbing works better with more teeth on the gear as there is better engagement, trying to cut less than around 20 teeth can give poorer results.
@@AndysMachines my hob is 7mm pitch, im trying to to cut a 2.25 module gear, first I tried on a nylon blank but the teeth were a bit skinny, next I tried aluminum and it chewed up all the teeth. Gotta keep trying
Just some constructive criticism from my perspective: I would enjoy more explanation throughout the process. Instead of just machine noises, and an occasional brief pop-up description. I'd enjoy learning why you're doing, how your doing, what lead you to those decisions, etc. Thank you, very interesting though; gear hobbing is something I really want to get into.
Yes, I know what you mean. It's hard to know what level of detail to go into sometimes and I don't want to make the video too long and boring. I'm going to be doing some follow up videos related to gear hobbing where I'll focus more closely on different elements with more detailed explanations, calculations, etc...
Pardon my ignorance but I thought hobs worked like worm gears, is it not possible to just have the stock be freely rotating, then when the hob makes contact it transfers its motion to make the stock rotate at the correct speed?
Yes, there is a 'worm effect' and cutting gears this way is called 'free hobbing'. However when the hob first touches the blank it is not at the final radius of the gear so you can end up with one too many teeth (or even half a tooth extra!). For this reason when free-hobbing you usually need to gash the blank first with the correct number of slots to keep things in line.
It's actually faster and makes a lot less mess with a hacksaw. It does take more physical effort, but I usually saw the bulk off then clean it up on the mill.
Not too often do I happen to find a new (to me) channel that absolutely amazes me - this is one of those! The care that is clearly put into every shot, camera angle, or animation to carry out some important point is truly impressive!
Well, thanks for the appreciation! 😁
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Just found your channel. Nice to see a UK channel for once doing this stuff well.
25.025 is very, very precise.
The lack of run-out throughout is almost unsettling..) That's a well dialed home lathe.. Great work!)
You are strong . Cutting metal without power tools. Salute
It's a real joy to watch a professional at work,
Keep up the good work.
Finally a machinist channel not using stupid inches
Remarkable work and great editing. Truly a pleasure to watch. I am curious about the ratio of (1) the time spent planning to (2) the time spent in set up to (3) the time spent cutting.
Thanks! Time spent cutting (per gear) is probably the least. Setting up is really just like tramming a vice, though I may have to do both the hobbing attachment and the mill head. Planning and preparing the blanks etc. can vary wildly though often it's just some simple arithmetic in my head and turning a piece of bar on the lathe.
You should consider adding trepanning to your skill set. The next time you want to cut a round round out of rectangular piece of material it is a lot faster, easier, and leaves a much better surface finish that is concentric to the rest of the part. If you are concerned about the inner part falling out at the end consider leaving a thin web at the end of the cut.
Yes, I sometimes trepan thin material on the lathe, but these plates are 20mm thick (~3/4") which would need a very long thin trepanning tool. I suppose I could cut from both sides though. Any time I want to remove a lot of material quickly my first thought is usually some method of sawing it off.
@@AndysMachines Hi Andy, Thanks for the reply. However, thickness of material does not limit trepanning. It is a great way to remove material. You clearly have the ability to grind trepanning tools. It is a lot like grinding a boring tool that creates shank clearance on both sides of the cut (similar to a hole saw creates a curf wide enough to allow the body of the saw to follow the teeth down the hole). It is not difficult if you understand the geometry and the clearances necessary to manage your chips without hitting the stock on the inside or outside during the cut. I encourage you to look into it.
Regarding your comment on sawing off the material, the way you did it in the video created a situation where you had to deal with an interrupted cut on the lathe when you cleaned up the OD of the part. Interrupted cuts are always time consuming and can damage your cutter if you take too deep of a cut or use too high of a rotational speed. If you insist on using your band saw to cut off the square edges of a "round" part then you should consider going to a more narrow blade on your band saw. With a narrow blade you can scroll around the inner part and minimize the stock left for later removal. Once you get used to this you will minimize (or possibly eliminate) the interrupted cut and material removal.
Hope you are not offended by my comments but I am just trying to help you. I have over 50 years of prototyping experience and figuring out how to make things. It is hard to go away from old habits (especially in matters of things you have figured out for yourself). However, the faster you get at doing things the more magical things you will create. Any you are a very creative guy. I have a couple of other simple suggestions for you but this is getting petty long so I will make another comment after a while.
Cheers,
R J
@@rjserra5535 Not offended at all! Thanks for taking the time to write such a long comment and share your knowledge.
I have ground trepanning tools in the past by hand from HSS blanks, I usually made them fairly short as that's all I needed and I found making longer ones more time consuming and the tool itself becomes more fragile with length.
I don't actually have a bandsaw now (have owned several in the past), so I often go for the quick and dirty 'lop off the corners with a hacksaw and true it up on the lathe.' An irregularly shaped blank does take longer, but I generally use HSS tooling on the lathe so the interrupted cut is not really a problem.
Happy to hear any other suggestions!
Excellent video thank you, heaps of operations I've never seen before in practice.
So much work went into those parts. Respect 👍
This was very interesting! I did not know I wanted to see this until you made this video. It is highly awesome you have the knowledge and attention to make your own machines. Love your Terminator build and now I know how you make the tools you have to accomplish this.
Yessssss...........last time I cut some gears was 15 years ago.....still nice to have a dividing head to do all that.......at the time I used a hand ground fly cutter to get the gear cutter profile.......just too many gear profiles and sizes to lay out for a couple of sets of gear cutters......and a hob does the job in one hit after you gash the teeth.
Actually with a powered hobbing spindle you don't even need to gash the gear blank, you only need to do that if 'free hobbing' (and even then you can still end up with the wrong number of teeth!)
@@AndysMachines 1
An excellent video. About 2 minutes into it I realized I had put everything else aside and was giving it my undivided attention.
I'm looking forward to part 2, and have subscribed.
Glad you liked it! Part 2 coming very soon...
Wow! Really impressive build Andy! You've made me want to build my own. Cheers, Morgan
If you make a lot of gears, this way is so much better!
@@AndysMachines Richard Gere (read gear) would be proud.
Great video and AndyMachines understand what so many youtubers do not. You did not put background music on. Seems so simple but so many others fail so badly and put on loud stupid/offensive music when they should not.
Yes, I learnt that lesson a long time ago, whatever music you use won't be to everybody's taste.
So very awesome and precision!
Loving the sonar ping for xray view!!!
Great job!
Keep em coming!!!!
Excellent project!
You might get this question often: how would you cut gears without the mill spindle being able to tilt?
I think I did get this question from somebody who had a mill with a head that didn't tilt. You can't just tilt the work spindle an additional angle to compensate, since the feed direction must be parallel to the teeth. If you used a large diameter hob with very small teeth and hence a very small helical angle then you could probably get away with not tilting the head (the clearance angle ground on the teeth would be greater than the error, so the teeth would still cut without rubbing)
Fascinating! Thank you so much for sharing your knowledge and experience. I learned a lot. Gears, I love the technology.
Very good video on a very interesting topic. Can't wait for the next episode.
Really nice work for accurate gear cutting tool using different sizes n ratio
Just discovered your channel. Love it!
Hi Andy. Some impressive heavy(ish) and precision work there. Well done.
Regards Mark in the UK
Thanks! Not really all that heavy, though reaching the limits of some of my tools, particularly the lathe steady rest which really won't go any bigger. Because this is a machine that will be making parts for other machines, I'm trying to make it as accurate as I can so I don't have errors stacking up on top of each other. 🇬🇧
Hello Andy, Amazing videos and thanks for all the effort you put into this. Mechanically I can do about anything but electrically I struggle. Can you give me some part numbers on encoder options. Thanks!
Hello Mr Winky! I enjoy watching your channel!
The encoder I used for this project I actually cobbled together from some parts from an unknown make servo motor and a codewheel I made myself. For general use I've always used the HEDS range of encoders made by HP/Agilent, now made by Broadcom I think. I like these since you can buy the read heads and codewheels separately, or the whole thing as one unit. I know a lot of people have replicated this project using the 38S6G5 type encoders which are very cheap on ebay/AliExpress. These can't be directly mounted on the spindle of a milling machine however, you would need to attach a timing pulley or gear to drive it. Directly mounting on the spindle is usually better, but encoders of this type with a large through-bore are specialist items and can be expensive or hard to find. You can always make your own, either how I did, or even from scratch by building the read-head from simple components. (I've said before I'll do a video on encoders one day, how they work and how to make them, I'll get round to it one day!)
@@AndysMachines Great info! Thanks. I may have to use a belt on my mill. It's possible I could mount a disc on the top of the spindle pulley but the encoder would end up inside the step pulley. Doable but the belt would probably be easier. I'll do a video on the build and of course link to your videos. You do a great job on the videos. Thanks!
I'll look forward to seeing the video! Any issues/questions just let me know.
@@AndysMachines Thanks, I appreciate this.
@@AndysMachines Hello Andy, the specs on these encoders are in Greek (to me). I can make a belt drive or disk type work. I assume the disc can be larger in diameter as long as it has 150 slots (with equal slot width and gap?). Can you suggest a specific part number for either one or both styles? Thanks.
Это просто шикарно !! Золотые руки !!! Начало - нарезание эвольвентного профиля с помощью сегментной фрезы и методом обкатки инструментальной рейкой (прямой зуб).
Very good job man love u from India Punjab Amritsar sport Indian farmer
The x-ray view was cool!!
Wow…. So inspiring. Thanks for taking us along on the ride and show us all that is possible. 👍👍😎👍👍. I NEED to watch more of your content. 😉. This channel should have many more subscribers. I did my part just now - I’ve subscribed and turned the bell on. 😊
Superb machining skills. Superb video too. I feel a bit cheeky for asking, given how good this was, but would be nice if you narrated it - you know - why you made certain choices, what pitfalls you had/avoided etc. But I'll be more than happy just to see it in action on the next one. Thanks for sharing!
Thanks! It's hard to know what level of detail to go into with narration, captions etc. I assume that anybody watching a video like this would already have a fair amount of engineering knowledge. I don't want to make the videos too long by explaining every little thing, people can always ask in the comments if anything's not clear.
Have you ever used a spiral point tap they cut so much nicer than those raspy straight flute taps.
What I really would like to know is how it is that you get the spindle and your machine on the same page.
Just found your channel. Excellent stuff - interesting projects, well explained, graphics really helpful. I'm hooked. Thank you.
Awesome, looking forward to the second part 👍
Very well done. Just wondering why you don't use carbide insert tooling on the lathe
Thanks! Actually I do use carbide sometimes, I just prefer HSS on my small lathe.
This channel is impressive!!! Great work!!!
I thought this hub will turn the blank by it's self and all you need is to set 20 degree angle to match the cutter angle printed on it.
No ?
That's called 'free hobbing' and it can work but more often than not you get poor results since when the cutter first contacts the blank it is not at the correct pitch circle diameter and so turns at the wrong speed giving you a different number of teeth to that expected. Sometimes it will sort itself out as the cut progresses, but it's hit and miss.
Outstanding video. Loved the x-ray demo. Can't wait for for next episode.
16:59 song you own a drill press you could've used for this hole making operation? I think that if you had one and you set it on the lowest speed and attached a weight to the plunge handle you could've had it a lot easier.
At the time of filming I didn't actually have a working drill press with a chuck that would hold this hole saw (hex shaft). It won't fit well in a round collet in my mill and the drill chuck I have for the mill is too small. However this corded drill has a lot of torque on low speed and it handled the job better than I was expecting. I could also have done it in the lathe but it would have taken longer to swap the 4-jaw chuck and back.
Excellent! The commitment , precision nice , specially your mini lathe do fantastic , share us where to get for the mini lathe . Thanks
Now, that was a great video, thanks so much. Can’t wait for the next one.
Thanks! Here's the next one: th-cam.com/video/VJOem40ggkI/w-d-xo.html
I wondering how helical gear is possible . You need electronic diffration.. plz explain...
No, you don't need any advance or a differential such as you might have when milling helical gears on a horizontal milling machine. You only need to tilt the attachment to the helical angle and take the cut as normal, this is because I am using a hob and feeding in line with the teeth.
Obviously you built a CNC hob fixture. Which means you need a hob cutting tool. Something if DYI starting as a ACME threaded with the proper profile for the gear be it 14.5, 20, or some special pressure angle degrees and the other features like root dimensions. Then cut to produce teeth and hardened. Is the hob made or purchased?
I have both hobs I bought and ones I made, I've built up quite a collection over the years. I make them from O1 tool steel (drill rod). Screwcut, then teeth cut in the mill, hardened and tempered. My homemade ones don't have the full relief on the teeth the commercial ones have, but they seem to cut just as well (use plenty of cutting oil). it's useful to be able to make custom hobs for things like splines and toothed pulleys, not just gears.
Just found this channel, you are a really clever engineer, great video, I'll shall be checking out your other videos. One question, I did an engineering apprenticeship 25 years ago and HSS lathe turning tools were old technology then. Is there a reason you still use them? I only do a bit of machining at home now but use only insert tools as HSS is far to slow for me. Again super video!
Thanks! Yes, I do use carbide insert tooling as well, but I've just always used HSS and I like how I can quickly grind any shape tool I need. Also my lathe is only a small bench-top model, it doesn't have the power for really heavy cuts.
AndysMachines thanks for the response and fair comment. HSS still has its place for sure. The hobbing attachment is beautifully made love how you did the scribed degree graduations and etched the numbers. The video has inspired and opened new opportunities through watching it, just shows what you can still do with manual machines at home if your clever enough.
a great and informative video. do you provide plans for your gear Hobbing attachment
I haven't drawn actual blueprints, there's enough info in the video to be able to reproduce it, it doesn't have to be exactly the same, you can modify the design to suit your own application.
Beautiful machining. A+ work
Thank you very much!
Gotta respect this dude
Well done, you made some very fine parts.
Always excellent, very enjoyable and instructive-excited to see part 2 Thank You Very Much ✅👍
Excellent work! I was surprised to see that you don't use any cooling.
First time on this channel, instant subscribe. You do very nice work.
Thank you very much!
Perfect job my friend.....can you give us a link with wiring diagram and program for arduino?
I love your work. But instead of building a spindle from scratch, could I just automate my rotary table using a motor and your controller? Or is there a critical issue I am overlooking?
There's a couple of good reasons not to use a rotary table, the worm reduction is usually 40:1 or 90:1 which is much too high to be practical, though you can disengage the worm and attach a pulley to the back of the spindle. The 2nd reason is that most of these tables aren't designed for continuous rotation, rather for indexing or cutting short arcs and they usually have plain bearings that have a bit of play in them. The play is not much of a problem in normal use and locking the table can eliminate it, but for hobbing gears it does make a difference and will lead to too much material being removed between the teeth especially on gears with less than ~ 20 teeth. But if you can find a rotary table or indexer with good preloaded bearings that you can attach a drive pulley directly to then yes, this can make a very good hobbing attachment.
Great work. Very interested in seeing the completed project.
I am building the 1/10 scale Wilfred Heckert Lanz Bulldog Flammenfresser, and boy do I need to make a lot of gears!!
I've heard hobs mentioned but i could never picture how they would work. Until this video...Cheers ta. If
Yes, looking at one you would assume it cuts just the profile of it's teeth, but it actually takes many small cuts to produce curved gear teeth.
I have never found a hole saw that size that would cut through that deep and big of a piece of steel
What brand did you use
It's a Sandvik (17:01) but any decent bi-metal type should do it. Keep the speed low, use cutting oil and clear the chips frequently. You can also drill a small hole all the way through in the path of the hole saw and this will let the chips fall through, though I tend not to do this as I find the slug removed by the hole saw very useful (this one actually became a gear for another project!).
Hi, Andy, I have been a long standing admirer of your most excellent efforts and I must have watched this video and part two at least ten times. Being a well seasoned retired pensioner I now find myself with countless hours of time to put some of my misspent skills to a use. One thing I would love to make is a Hobbing Attachment like this. Did you ever publish any drawings for this? If so can I beg, borrow, barter or at the outset buy?
Once again I congratulate you on your knowledge and skills and your unselfish way in which you share your your knowledge with the rest of the World. - Thank You.
Thanks Keith for the comment, I didn't actually produce drawings for the attachment as none of the dimensions are critical. You can alter the design to better suit your own needs or make use of whatever materials you have to hand. If you only want to cut spur gears (rather than helicals) then the attachment doesn't need to tilt and can be much simper. All you really need is a shaft rotating between two fixed bearings that you can attach a pulley and stepper motor to.
Nice craftsmanship!
on 20:59 why are you using z axis descend (with repeated passes like it was a drill) with the mill instead of using the y (or x) axis in that operation?
I mean why not directly do like you are then doing at 21:07
sorry for the dumb question, I am learning.
Many thanks!
It's often quicker to remove material this way, this part is quite thick and would take several passes to mill sideways, you can plunge cut more aggressively than mill sideways on a thick part. It also reduces uneven wear on the side of the endmill.
At 21:07 I am doing a light finishing pass at full depth, note that I am doing this in the climb milling direction which produces a better surface finish.
Sure your parts look nice, but your dial indicator is obviously broken. It should be flopping wildly, like mine does.
Thanks for posting this excellent video. Looking forward to the follow-up video.
Thanks a lot for the video! 👏👏👏👏👏👏👍👍👍👍
Is a gear cutter for cutting a rack the same tooth shape as the hob? It seems like perhaps with multiple passes, a rack cutter could cut any number of teeth by turning the gear a bit and moving the cutter the same amount to simulate what the hob is doing.
Yes, a no.1 gear cutter (135 teeth - rack) has the same tooth profile as a hob, though obviously the teeth are not arranged in a helix, and can be used to cut any number of gear teeth by rotating the blank and moving the cutter along the tangent an equal amount (measured at the pitch circle diameter). Using this method you can even cut less than 12 teeth which you can't do even with a number 8 cutter in a normal set. If fact you don't even need a gear cutter to do this, it can be done with a regular tool like an endmill or (better) slitting saw. I have another video explaining this method: th-cam.com/video/eC-OctJoWv4/w-d-xo.html
Awesome work Mr. 👍.
Andy
Real question from ignorance in relation to hacksaw corner removal: you used hacksaw because it’s fastest? Or on a milling machine you are wasting a valuable cutting head? Or???
(no trade background, recently retired and about buy a metal lathe 😊)
Sawing is always fastest, compared to drilling or milling the material away and turning it all to chips. Sawing by hand does take some effort, a bandsaw would be faster, but I don't have one. An angle grinder with a thin cutting disk is another way, but also very messy if you only have a small workspace.
@@AndysMachines cheers! Thanks 😊
So impressive. Seeing machinists at work has me looking any machined part, however mundane, and thinking about the machine time needed to make it. Or in the days before CNC, what complex jigs or human effort was needed to machine the parts that went into a car, a jet, or any machine
Oh, it was nothing, everything just came naturally, I always thought about how long it took, how much skill and hard work was done to get to where we are in this day and age.
I wonder how was that tapered made rolling the saddle in as you showed.
You mean boring the Morse taper?
Very nice. Thank you. I usually just skip to the end on Build videos to see the final product, but your editing of the video was so well done that I watched every minute.
Question: Instead of cutting the corners off the flat stock with a hacksaw at 5:00, and then later spending a great deal of time removing the rest of the stock in the lathe at 8:50, why not use the rotary table and a small roughing end mill to do the job? I find this work well.
Thanks again. Looking forward to part 2
I'm glad you liked the video! Yes, the rotary table is just as good a way of doing this, though personally I only tend to do that when I don't want a full circle (such as when I rounded off the corners of the frame). I roughly knocked the corners off first just so I could centre the part in the 3-jaw on my rotary table (with shims and moving the chuck on the table) to cut the T-slots. I left the final finishing of the faceplate until everything else was welded, bored etc. in case there was any movement.
Your video popped up in a sub-feed from a mini lathe video. Overall great video. Would you try to keep the sound of the machine noises at or below your level of speech loudness? I had to repeatedly adjust the volume.
Thank you for sharing this wonderfully inexpensive modification!
You do some really nice work. I’m really impressed. But I’m surprised that you don’t seem to use any machine coolant or even thread cutting compound such as Trefolex. We always used both. The surface finish on threads in steel for instance is greatly affected by tapping dry. Brass is a different story, but we would have been seriously reprimanded for going in without Trefolex. You can imagine the jokes that went along with this rule.
Thanks! As for the coolant, I can see I'm going to have to get a mister and have it visible in every shot, I seem to get this comment a lot! I DO use cutting oil, even flood coolant, but I generally don't show the application of it (though you can see it's there) and I don't use flood coolant in the videos as it would obscure what's going on. Maybe I don't use as much cutting oil as some machinists or reapply it as frequently, and I don't use it for everything, but yes, always when tapping steel.
8:41 It must be very handy having a lathe with a crossfade control!
Yes, it speeds jobs up immensely! 😁
You do beautiful work. Only thing I would advise is when milling I would blow some air or better some coolant mist to clear the chips. You are forcing your cutter to recut some chips. I think that's kind of hard on it.
Thanks!
I generally don't use compressed air on the mill to avoid blowing chips everywhere (I only have a small workshop). I sometimes use a small paintbrush to wipe them away and I usually do a light climb cut for the finishing pass to avoid recutting chips.
@@AndysMachines it does make a mess. I mostly cut stainless in my job. I started getting a lot less damage on my end mill flutes after I started using air to blow chips away from the cut. Air plus some cutting oil mist or flood gives a much better surface finish on stainless when milling a slot. So much difference I couldn't believe it the first time.
what brand is your milling machine?
thanks
it's an RF45 clone. A largeish bench-top machine but still really a hobby type machine rather than a full size industrial machine.
I had hope when I saw the "Toolzone indicator" thinking I can afford this hobby, then you brought out the "mitutoyo micrometer"😂.
Cool I never seen gears cut like that, thanks for the education, please include more explanation of why you are doing operations and which order for beginners like me. Thanks
Yes, I only have one Mitutoyo and it's 0-25mm but it will actually measure slightly over that, which can be very useful in situations like this. Fortunately I rarely need to measure things bigger than 25mm to 1 micron accuracy.
Super project! Thanks for sharing!
Thanks for watching!
Thanks for giving some ideas for my project
Great engineering and good watch! Cheers
get yourself a mister. Use the expensive synthetic stuff and use it very sparingly with high air flow about 35 - 40 PSI. It'll improve finishes enormously because it'll blow chips away keeping you from recutting them. It'll also extend tool life and allow you to increase speeds and feeds markedly. For that T slot I'd use a flood.
I was concerned about a mister in a small shop. But the synthetic stuff is non toxic and I use so little.
Hello sir,
How do you define the Rpm for the blank during hobbing ?
I know it have to be synchronise but I dont find any calculs to do it …
Thanks for your answer
The blank just turns as the speed of the hob divided by the number of teeth you want to cut in it. Each rotation of the hob cuts one tooth spacing. (For a single-start hob. For multi start hobs you divide by the number of teeth, then divide that number by the number of starts)
I used to run two cinninati hobbing machines 8 hours a day 6 days a week. Fun wow
Hi where can I find information about the calculation of gear hobbing? I’m also doing some projects involving gear hobbing .
I'll cover the actual hobbing in the next video. The calculations are nothing more than a simple division from the milling spindle to the hobbing spindle. There are also a few basic calculations relating to the size of the gear blank vs. no. teeth (and helical angle for helical gears) depth of cut etc. these calculations apply to all gears and there's lots of info online.
Hi! Excellent work! I have a question Is a differential mechanism for helical gears necessary? Like the hobber gear machine have? Thank you for share your work
Thanks! On a traditional universal milling machine where you have a gear train driving the table feed, it's normal to use a differential to advance the gear as it feeds, since the direction of feed is not parallel to the teeth. With the method I use here (I won't claim to have invented it) the 'advance' happens automatically since the gear blank is tilted and the feed direction is parallel to the teeth (not to the axis of rotation of the gear).
It's amazing. Are you using one of the CAD software for your projects?
I do design things in CAD, though rarely the whole machine, just the parts that I need to calculate some values for, or if I want to play around with the design to help me visualise it. I use Vectric and Turbocad packages. I did try Fusion 360 but didn't like it.
Excellent 👌. Thank you 😀.
Thank you 😀.
I know everyone can build the attachment anyway one would want BUT at 80 years of age , is there anyway to get hold of your prints that you made yours from?
I didn't actually make any prints for this, I just built it mostly with what materials I had to hand as that was quicker. The only parameter that was important for me was to make the centre height match a tailstock I already had.
Well I guess I'll be building a hobbing attachment in the future. Thanks for extending my ever growing project list!... ;-) Subbed.
Awesome work! Although it was painful to watch you hacksaw the corners off that plate, lol, been there and it's not fun.
Next time you hole saw a hole... scratch the surface with the hole saw, then drill a hole tangent to the scratch mark. This hole allows chips to fall out of the cut and prevents chip packing in your hole saw gullets. You'll cut faster and with less heat giving you years more with your expensive, carbide tipped hole saws
Good tip! I always do this with wood and it cuts much faster (usually 2 holes on opposite sides). With steel I tend pull the saw out frequently to clear the chips and add more cutting oil.
Hi Andy, just found your channel, excellent content. I have downloaded the files for the gear hobber, just a couple of questions if i may,
1: what does one do with the MAIN . asm file?
2: when I use the CMD window as per the instructions I get the following error System wide configuration file is ""
avrdude: can't open config file "": Invalid argument
avrdude: error reading system wide configuration file ""
Any idea what I am doing wrong?
By the way spotted the post about COM port number, mine is on COM 5, altering this makes no difference.
Hope you can help me I would love to have this facility in my shop.
Best Regards
Ron Cummings
Hi Ron, The .asm file is the assembler file that the .hex file is compiled from. You don't actually need it, but I included it as some people might like it for reference, or to edit it if anybody wants to modify the code.
2. It sounds like avrdude can't find it's configuration file (avrdude.conf), either because it doesn't exist, or maybe because it's not been told it's name? Have you just installed the arduino software? If so you might need to use the IDE itself to upload a file to the board (eg. with 'hello world' or any example project). This might initialise the configuration, but I'm really not an expert on arduinos, maybe somebody else reading this might know the answer?
Yes, you will need to set the -PCOM command to suit if you are not using COM 6, I neglected to mention this in the video, but I have since updated the 'how to' text file.
just beautiful dood. well over 20 minutes and the best i will spend today!! i love the lathe tool that did much of the turning, it seems to be have two sets of super imposed geometry? also i am curious, at 5:25 you use a dti fixed to the mill with the finger on the bore of the work, which you then spin and show the clock not moving (so nice!), are you checking conecntricity of said bore or are you checking the work is centred under the spindle of the mill? if the later then please can you explain your procedure here? fair play with the hack and hole saws...i know those jobs! cheers again and look forward very much to watching the rest.
Thanks! Not sure which lathe cutter you mean, but with the dti I'm centring the workpiece on the rotary table by using shims on the jaws of the 3-jaw chuck and also tapping the chuck around on the table (the workpiece is a rough octagon at this point). This is so I can cut the t-slots accurately, it's not critical to have them centred but I wanted to do a good job of it.
I love this video so much
Do you generally not use metal cutting oils? Does it have any advantages?
Generally yes, but not always. Also when videoing I sometimes do things differently and avoid things like flood coolant which make it harder to see what's happening.
Cutting oil is for the purpose of preventing the chip from welding itself to the cutting tool or the work. It is an absolute necessity with certain materials and processes. It can be of little value in other cases. For example, center drilling 304 or 316 stainless always requires cutting oil. Threading pipe, especially stainless pipe always requires cutting oil. Further, not just any oil. Sulfur based cutting oil is the minimum. Otherwise, you can count on breaking your dies. Even deathly expensive pipe dies made for stainless will chip without the proper cutting oil. I know this from first hand experience, not just from a book. To restate, don't try to use Tap Magic to thread stainless pipe.
Hi i made a hob, what if i place my gear blank on a shaft with bearings, instead if driving the gear blank? Will it work
That's called 'free hobbing'. It can work but you need to be very exact with the setup or you often end up with one more or less teeth than you want. It helps to gash the blank first with the right number of shallow cuts to give the hob somewhere to start.
@@AndysMachines hi thanks for the reply. Will it produce accurate teeth? I did cut a nylon blank but i feel the teeth are skinny compared to the hob, do u know why?
It may not be as accurate, the problem is that the hob is driving the blank like a wormwheel so if the hob is not cutting at full depth it will want to turn it at the wrong speed. It's better to feed the hob in axially already at full depth, rather than feed into the blank radially. Also free hobbing works better with more teeth on the gear as there is better engagement, trying to cut less than around 20 teeth can give poorer results.
@@AndysMachines my hob is 7mm pitch, im trying to to cut a 2.25 module gear, first I tried on a nylon blank but the teeth were a bit skinny, next I tried aluminum and it chewed up all the teeth. Gotta keep trying
Nice work! 👍
amazing vid!looks very promising,going to watch the others too!
Very much enjoyed this.
Nice job 👍
Wonderfully done and some great effects.
Just some constructive criticism from my perspective: I would enjoy more explanation throughout the process. Instead of just machine noises, and an occasional brief pop-up description. I'd enjoy learning why you're doing, how your doing, what lead you to those decisions, etc.
Thank you, very interesting though; gear hobbing is something I really want to get into.
Yes, I know what you mean. It's hard to know what level of detail to go into sometimes and I don't want to make the video too long and boring.
I'm going to be doing some follow up videos related to gear hobbing where I'll focus more closely on different elements with more detailed explanations, calculations, etc...
Pardon my ignorance but I thought hobs worked like worm gears, is it not possible to just have the stock be freely rotating, then when the hob makes contact it transfers its motion to make the stock rotate at the correct speed?
Yes, there is a 'worm effect' and cutting gears this way is called 'free hobbing'. However when the hob first touches the blank it is not at the final radius of the gear so you can end up with one too many teeth (or even half a tooth extra!). For this reason when free-hobbing you usually need to gash the blank first with the correct number of slots to keep things in line.
@@AndysMachines thank you for the info
Nice. Roll on part 2!
Here it is!: th-cam.com/video/VJOem40ggkI/w-d-xo.html
very good. when is the second video ?
Thanks! Next video on this should be within days, I'm just finishing it off.
You have a mill and u used a hacksaw to remove the corners? Should have just milled the off.
It's actually faster and makes a lot less mess with a hacksaw. It does take more physical effort, but I usually saw the bulk off then clean it up on the mill.