# Gear cutting hob



## lugnut (Jun 21, 2009)

I'm at the point in my construction of the Chuck's Single engine that I need to cut the gears. I'm planning on using 32 Dp gears and I want to make a gear cutting hob. Does anyone have any ideas or instructions that would be willing to share with me?
Mel


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## gmac (Jun 21, 2009)

Mel;
You might find some info here;

http://groups.yahoo.com/group/gearcutting/files/
http://helicron.net/workshop/gearcutting/
http://helicron.net/workshop/gearcutting/links/

I've seen other articles but I'll have to sniff around my hard drive - I'll post if something is found.

Garry


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## Dunc (Jun 21, 2009)

Have a look at
Making Gears the Easy Way by Jose Rodriguez. This is a SmartFlix video 
rental. No connection except as a customer. 

3w.youtube.com/watch?v=nMS2un-kbg0 
(Had to write tghe url this way to avoid direct link to video) 
One of a series of hobbing gears by "Hobbynut"


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## ksouers (Jun 22, 2009)

Mel,
Here is a link to an article written by our own John Stevenson many years ago.

http://www.metalwebnews.com/howto/gear/gear1.html

In it he describes how to make a four-lobe hob and all the calculations necessary.


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## lugnut (Jul 4, 2009)

Here are few photos of what I have accomplished so far on my gear hob project. 
I cut the tooth groves on the lathe to .09818 apart. I think that is the correct spacing??? I hope to cut some 32 DP gears.

Then in the RT on the mill I indexed and cut with the saw, 8 groves down the length of the the Hob.





Using the saw with the bottom of the blade set to the center, sawed the flat surfaces into the groves.




Then heat treated the hob. then I honed the cutting surface of the teeth with a diamond hone.








Will it work?? I have not had time to try it as yet. I've been helping a friend set up his line shaft shop.
Mel


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## vlmarshall (Jul 4, 2009)

How far below (behind) center are those teeth?


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## lugnut (Jul 4, 2009)

Vernon, I set the bottom of the saw blade on center as indicated by my DRO. that should make the vertical edge of the tooth on center. I took measure of the diameter of the hob, then touched the bottom of the saw blade and zeroed the DRO, then lowered the blade 1/2 of the diameter and locked the Z.  and then cut the eight groves. then moved up and cut the flat surfaces into the grove using the index of the R/T to move 45° each cut.
Mel


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## John S (Jul 4, 2009)

Yes it will work.

Go up a few post and find the link to the You Tube video's by hobby nut.

These are brilliant, clear, concise and very accurate in method.

DO NOT GET THE JOSE RODRIGUEZ VIDEO.
It's totally crap, bad formatting it's that blured you have no way of knowing what the teeth look like.
the calculations are way off, for a start he had Pi wrong in every calculation. He's working on TPI not DP and is attempting to cut these on some home made machine that's part Sherline and part high tensile licorice.

More to the point he's asking serious coin for this load of bullshit whereas Hobbynut has put far more up in 6 video's for free than this clown has managed in his expensive video.

John Stevenson


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## vlmarshall (Jul 4, 2009)

lugnut  said:
			
		

> Vernon, I set the bottom of the saw blade on center as indicated by my DRO. that should make the vertical edge of the tooth on center.... then moved up and cut the flat surfaces into the grove using the index of the R/T to move 45° each cut.
> Mel


Oh yeah, duh, I forgot about tooth rake. It looked (to me) like the teeth were way behind center, and I was worried your profile would come out wrong. :-\ Nice gear hob, one day I'll try this method at home, right now I don't know much about it. 

I've cut a lot of gears, splines, drills, taps, and assorted cutters at work, but always one tooth at a time... and no gears small enough to use on a home project! ;D Thanks for posting this. Between your posts and HobbyNut's videos, one day I'll get off my butt and try it myself.


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## lugnut (Jul 4, 2009)

John Stevenson is correct when says that the Hobbynut series on You Tub is a great learning tool for any one who thinks they might want to cut their own gears. I think there are seven session plus a couple of make up videos and all well worth looking at. 
Mel


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## lugnut (Jul 10, 2009)

Well I cut some gears tonight. Used some 6061 and took it slow and easy, taking only .015 on each pass. Every thing worked just great and I'm sure I will have to mess with the cam gear a little more to get the cam right. But the Hob I made worked great. The two gears are 32DP 32 and 16 tooth. 




















Mel


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## vlmarshall (Jul 11, 2009)

Congrats! Good-looking gears. :bow:


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