The video is a couple years old, however I've enjoyed them again today. Thanks for making them.

There is a way to make the plunge cuts easier, especially on a machine with limited rigidity.  First start with a light cut as you did.  Then move the tool sideways a short distance from the centerline of the cut.  This broadens the cut so the next deeper pass only cuts at the pointed end of the tool, lowering the cutting forces.  Keep advancing and going sideways less and less until at the end you are straight plunging.

It is very simple when you have Module type gears.
M is the Module, and is the head height of the tooth.
And is the distance from the primitive radiusto the external radius.
The Primitive Diameter is Z x M, where Z is the Number of teeth, and M is the Modulus.
There is another value that is "The "root height", that is equal to 1.2 x M.
I measured some gears with this method without any problems.
Regards!!

Dimitrial pitch? Who the hell is this guy Dimitri? He has his own pitch? Wow!

This method works great!  By the way, at 4:13 it should be 3.1416 rather then 3.146

These cutters remind me of something I tried with large taps that have badly worn teeth at the working end. Set-up in a surface grinder with the tap held in some sort of indexed and the leading edge of the flute rotated around 3 to 5°. Grind the top of the teeth until you have a flat slightly wider than 1/number of flutes x the pitch of the tap. Then rotate the tap in the indexer to grind secondary clearance on the teeth. You now have a functioning roughing mill cutter. The problem is to use taps that fit in a collet. An ER collet works great for this as many taps have odd ball shank sizes. These taps do not work as well as a true rougher but for a home shop guy they will suffice. Just don't push them too hard.

Very interesting. Good work.

Thanks great job

Very interesting video 👍👍💫 Thanks

you should mill first and hen turn, you can take of more like that and its faster and more precise

Great job, thanks.
I have 3 Atlas lathes, not enough gears.
I’ll watch all, just started the third one.
Old Bob

Something is wrong with your lathe.  The headstock seemed to be bending back when you did the center drill of the end.  You should put a reference surface on the cutter that represents the pitch diameter (tangent to the pitch diameter of the gear when the gear is finished).

It would be easier to get a acme threading insert and make your hob angles are already there 29 degree and carbide also

Whole depth for 14 1/2 degree pressure angle, is 2.157/P where P is diametral pitch. Diametral pitch is  N/D, O.D. of the gear blank is N+2/P. But overall, you have convinced me, that I have got to make a hob. Thanks!

very nice job

Great videos I've watched all 4 of these hob making videos . Does it matter what diameter of drill rod you use ?

Pretty cool man! Love seeing people make there own tools.

Hi Robertt, dont know if your still checking comments on this 2 year old video but hope you are--Great info you provide in your vids. ive watched many gear making vids on youtube and yours are the only ones that go through the steps and the math to do it. All the others just say , get a cutter, or a hob--put it on your 3,000 dollar Mill and put a blank in your 900 dollar indexer and make the gear and the vid is about 3 minutes long, so thank you very much. if you do another gear type video, could you do one one making a --worm and worm gear, would Really appreciate it, thanks again

Loved the video.  Did you built the holder that held hobby on the mill?

My only question.... how did you rotate those vice grips clockwise so many times when your other hand was holding the torch?