Making a replacement gear for thread dial indicator

Those gears work okay even when badly worn or misshapen and I am not sure it would not work properly with a tooth missing. I have seen straight spur gears used which did not fit the leadscrew at all well. It does not take much contact to rotate the thread dial. I have not tried it but I suspect you could cut a new gear from soft material by gashing a short section of the leadscrew at the end and using it as a hob. Otherwise you might get any kind of 4TPI tap or bolt and use it as a hob.

Don Young (USA)

On Jul 17, 12:39=A0am, "Martin Whybrow" wrote: would be where to get a 1 1/8" x 4 TPI Acme tap for a

Try Tracy tools

In article , Don Young writes

Whilst I agree with Don, if it were me I would take the thought a step further and try a repair. I would cut a slot in the gear where the missing tooth isn't, so to speak, and insert (using Araldite) a sliver of brass (or similar) a bit bigger than the teeth, then file it down to approximately the shape of the teeth. As Don says, the power transmission is negligible, and any tiny deviation in angular positioning due to deviation in shape would not be noticeable in this application.

David

Try Tracy tools

I've already checked the website and they don't have them that large; thanks anyway. Martin.

Thanks Don but I don't fancy gashing the leadscrew and I can't think of a lashup that would enable me to use it to cut the gear anyway, the through bore of the headstock is too small to try getting in the lathe! I'll dig around for a 4 TPI tap but they are a bit thin on the ground in my workshop, maybe I'll find one on fleabay. Martin.

Thanks David, that sound favourite so far. Martin.

Hi If you get stuck, contact me , I can probably make you a new gear. Peter