Change gear identification - help please

Could it be from a dividing head? This might explain the large bore and yet small tooth form. Such gears are commonly 40 or 60 tooth and mesh with a worm which in turn rotated under the control of standard division plates - apologies for egg sucking information if you already know this!!

If not a dividing head then I expect that it is a 'special' of some sort as the 1/4 key way and teeth that cannot be more than 1/8" at the root just don't add up to me.

Bob

Another possibility is that it's one of a pair of translation gears, which sit on a common keyed boss.

Why are you sure it's a change wheel? How many teeth?

Cheers Tim Dutton Dry-Dock Traditional & Modern canal craft repairs Vintage diesel engine service

127 teeth. I can't think of any other application for a gear with these teeth other than a change wheel.

However, you said the magic words 'translation gears' which lit up something in the dark recesses of my mind. I looked in Martin Cleeve's book on screwcutting, and he has a picture of his Myford, but with a

40-127 set of translation gears in 30DP, so chosen to save a bit of space.

So could it be for a large lathe (big bore) with a similar logic?

I guess I should rephrase the question: does anyone know what lathes have change gears with a 1 1/4" bore and 1/4" (wide) key?

Thanks.

John Montrose said

127 is a 'magic' number and I'm sure many here will immediatly know that it must be a change wheel for an imperial>>metric conversion.

Which make of lathe I have no idea.

JG

127.... the magic number :-) these are used in gear sets to convert imperial to metric ( normally for screw cutting )

For example... lead screw 8 TPI, pitch to cut 1mm

8 TIP = 0.125, 1mm= 0.039370078

0.125 / 0.039370078 multiply by 127 x 8 gives 127 / 40... easy to set up as a gearing.

In message , JG writes

2 * 127 = 254 25.4 mm = 1 inch