Author Topic: making a single tooth gear cutter. a different approach.  (Read 6392 times)

Offline wheeltapper

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making a single tooth gear cutter. a different approach.
« on: August 22, 2010, 04:01:03 PM »
Hi all

I've been trying to make a single tooth gear cutter using a form tool with hardened buttons and got nowhere.
I read on another forum someone used a cone drill to form the cutter shape but I didn't have much luck with that either.

so I thought' if I can't tilt the milling cutter tilt the blank.

so this is what I did,

first I fixed my dividing head to the mill with packing under the l/h side to give 5 degrees of tilt to the spindle.



then I held the blank in a collet
 
then I fixed a 120 tooth gear to the div head and indexed the spindle so the blank was square to the bed and took a skim across the end



then I fitted a normal milling cutter of a diameter equal to the dia of the button you would use doing it the other way, indexed the spindle 1 tooth which is 3 degrees,fed the cutter up to the blank and fed in the recommended cutting distance.
 
I placed the cutter on the side of the blank which would put the leading (widest) edge of the tip at the bottom and took a cut.


when it's across far enough, raise the cutter, index 2 teeth the other way and take the other cut.
 
finally index back to zero then go round 180 degrees which puts the cutting edge on top  and take a skim across the top with the end of the milling cutter to relieve the tip.

here's the finished cutter



here's an aluminium gear done as a test meshed with a change wheel.



the advantage of this is you can use any ordinary cutter.
 
there is a sad ending to this tho, I was so pleased that it worked I tried it on a steel gear blank , unfortunately I was in such a hurry to try it out I hardened the cutter but forgot to temper it and 5 teeth into the steel blank I chipped the end off.
 
but I can make another one.
so I did,


any comments  welcome.
Roy
I used to be confused, now I just don't know.

Offline John Hill

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Re: making a single tooth gear cutter. a different approach.
« Reply #1 on: August 22, 2010, 07:09:01 PM »
Very impressive Roy! :thumbup:
From the den of The Artful Bodger

Offline Sorekiwi

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Re: making a single tooth gear cutter. a different approach.
« Reply #2 on: August 22, 2010, 07:49:52 PM »
Very Nice!  And the thought that you can repeat the profile of the cutter if you need to must be reassuring.

Freehand grinding of form tools has always been hit and miss for me - I think it depends on how the planets are lined up, some days I get it right away, the next I cant get anywhere close...

Thats a Harold Hall dividing head isnt it?  How do you like it and did you build it exactly as the plans are drawn?
Mike, expat Kiwi in NE Ohio, USA

Offline wheeltapper

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Re: making a single tooth gear cutter. a different approach.
« Reply #3 on: August 23, 2010, 05:25:44 AM »
Hi
Yes it is Harold Hall, I seem to have a workshop full of his stuff :D

I only finished it a week ago and this is the first job it's done and it seems to have coped quite well.

it is according to plan except he made the spindle nose threaded but my lathe has a flange to bolt the chuck onto so I fitted this with a matching flange.
I used to be confused, now I just don't know.