Modules and cutting Wheels

[Tmuir]

I have an Elgin Pioneer aircraft clock that has a broken tooth on the ratchet wheel.

If you look around 9 o'clock on the ratchet wheel you will see the missing tooth.

 

Counting the teeth the wheel has 76 teeth and its outside diameter is 21.12mm.

Running this through the formula I come up with it being a 0.27 module cutter it needs.

The closest module cutter I see you can buy is 0.25. Is this too big a difference from 0.27?

Or do you think I could get away with it? I've got a reasonable workshop with lathe, milling machine (X2 clone) and dividing head, although I must admit I haven't checked it can do 76. Yes I could grind a fly cutter, but I doubt my hand is steady enough to get it close enough.

Wheel is 1mm thick so I should be able to get some 1mm gauge plate easy enough and broaching the center hole square will be a new challenge to me, but isn't that half the fun?

Do you think this is doable on an X2 mill, or will I be stretching it?

[oldhippy]

 It should be ok because you have play in winding wheels, the design of the teeth should allow that. As it’s a winding wheel and only one tooth missing the clock should still work all right. I’m thinking you are creating work for yourself.

[Tmuir]

So it would be ok to leave this wheel in as is?

I hadn't even considered that.

Out of all my clocks this one is the most important to me as it came from a RAAF Wirraway of which there was only a total of 755 Wirraways made and only 15 survive.

[praezis]

So much work for just one missing tooth! The tooth can be built up by laser welding and then reshaped.

I had repaired such damage also by cutting a slot of tooth width, inserting a piece of steel, hard soldering and grinding to shape.

Frank

[Tmuir]

Laser welding may be able to do it, but unfortunately I don't own one of those.

Yes dovetailing in a tooth is an option, but I wasn't sure it would be strong enough on a ratchet wheel, something for me to consider.

[praezis]

You don't have to own one. There are companies that do laser welding for money.

Frank