# Gear cutting on a lathe



## Kaleb

I've heard that you can cut gears on a lathe with some fancy setups. Does anyone here do it? If so, I'd like some hints for the fixtures or plans, particularly if you use it on a 9" South Bend or a copy thereof, since I am running a 9" Hercus, which is almost identical to a South Bend.


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## rake60

I have never done it but I was touring a WWII museum ship where a retired US Navy Machinist Mate told me about doing it.

The ship's machine shop was about 6 X 8 feet.
The machinery included an engine lathe, a heavy drill press and several grinders.

He said gear teeth were broached with a piece of HHS tool steel on the lathe.
The had no digitals so the indexing was all by eye.
Shaft keyways were broached on the same lathe with HSS tools.

He told me that ID keyways were broached using the drill press using hand ground HSS tools and showed me that process.

By that point, I had been in the ship's tiny machine shop talking to the Machinists Mate for a little over an hour any the wife 
was becoming a little bored so we had to move on in the tour.

I asked the old gentleman if he was a machinist after the war ended.
He said; "Hell yeah, some cranky inspector is no match of the fear of being dead in the water with someone shooting at you. 
It was easy money."

I'm rambling AGAIN. Sorry for that!

Rick


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## lensman57

Hi,

Have a look at this link, it maybe what you are looking for.

http://www.deansphotographica.com/machining/projects/gearcutting/gearcutting.htm


Regards,

A.G


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## prof65

Link doesn't work for me, an "L" at the end is missing:

http://www.deansphotographica.com/machining/projects/gearcutting/gearcutting.html



P.S. great site A.G., I love your 1" miniature lathe chuck.


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## basement_guy

This a website where somebody makes gears on a lathe.
There are some pics of the setup and the fixtures he uses.

http://users.picknowl.com.au/~gloaming_agnet/cq9325rev7.html


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## Charles Lamont

Basically you need to hold the gear blank on a spindle. You need an indexing device on the spindle. You need to mount the spindle so that it can be fed over the cutter. You need a means of adjusting the depth of cut. Don't know what is available for your lathe, but I have all the necessary accessories for my Myford. There is a photo of the setup here:

http://www.charleslamont.me.uk/Seagull/timing_gears.html


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## Boot

I used a mandrel held in my chuck and with a live ctr. in my TS. 
I then made a fixture discribed in I think a 1943-47 not sure on the year Popular Science magazine. I had to cut a 32 tooth gear for my thread dial.  The fixture used a 32 tooth back gear held on a spindle on one end and the blank on the other end.  I removed my compound from the cross slide made a round dove tail likes on the bottom of the compound mounted it on my toolmakers vise and installed it in the cross slide.  Only thing I regret was I didn't turn the fixture at an angle .  I cut it straight with a small saw blade in the mandrel.  It works like a boughten thread dial anyway. I have pictures located somewhere in this computer. If you are interested give me your e-mail address and I send them.   Boot in the USA


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## John Hill

This is how I cut some gears on a lathe..

The cutting rig..



geared slotter by aardvark_akubra, on Flickr


..and the indexing arrangement..



IMGP8706 by aardvark_akubra, on Flickr


These pictures show the machine set up to cut a slot across the end of a shaft but it is the same set up I used to cut some gears, among them the big gear shown on the repurposed drill press (I had to 'borrow' a lathe change wheel when making that first gear).

The indexer is mounted on a stub screwed into the end of the spindle and did not require any modifications to the lathe.

The single point tool was ground to match the space in a change gear near the size of the gear I wanted to cut.


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## tel

There are a number of ways of cutting gears on a lathe. All the above will work, or, popular among clock makers, is to use the lathe spindle to hold the blank, with some sort of indexing rig up, and have the cutter mounted in a sort of yoke - independently driven and fitted to a vertical slide for height adjustment.

I have tried a number of set-ups, with varying degrees of success, but the job is much better done on mill (h or v) or shaper.


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