Well, thanks for the appreciation! 😁

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Really nice work for accurate gear cutting tool using different sizes n ratio

If you make a lot of gears, this way is so much better!

@@AndysMachines Richard Gere (read gear) would be proud.

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. 🇬🇧

Thanks! Here's the next one: kzfaq.info/get/bejne/jLB_mNBllc3Lm30.html

Thank you very much!

Thank you very much!

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.

Glad you liked it! Part 2 coming very soon...

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!

Yes, I learnt that lesson a long time ago, whatever music you use won't be to everybody's taste.

Thanks for watching!

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.

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

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.

Thank you 😀.

Here it is!: kzfaq.info/get/bejne/jLB_mNBllc3Lm30.html

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.

Thanks! Actually I do use carbide sometimes, I just prefer HSS on my small lathe.

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.

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 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.

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 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)

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: kzfaq.info/get/bejne/m6ldgsalr9W7pmg.html

Yes, it speeds jobs up immensely! 😁

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.

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).

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.

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.

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.

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!).

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.

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.

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.

You mean boring the Morse taper?

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.

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.