Could this be useful?

[chrisp9au (Chris)]

I've had this brass 'thingy' sitting in my shed for years.
I have no idea what it is; I rather think it came from a garage sale.

It has a diameter of 226mm, and has 360 teeth which appear to be pretty accurately cut.
The centre bore(?) is 63mm with a steel reducer/collar which brings the bore down to 44.5mm

I'm wondering if I could use this as the basis of a DIY RA drive?
But where would I go to get a worm made up?

Some Brasso and a bit of elbow grease would make it look quite handsome!

I'd be interested if anyone can identify what it might be, plus ideas on putting it to good use?

Cheers

Chris

[bojan]

Definitely useful !!!
You just have to find (or someone should make it for you - any machine shop should be able to do it) the suitable worm (screw) with the same pitch (modulus) and you are in business !
A bit of diamond paste used to polish the worm gear after the assembly would make it perfect.
Of course, the worm should be at appropriate angle (so the teeth mesh properly) but this is not an issue - I did something similar in the past and it worked very well.

[chrisp9au (Chris)]

Originally Posted by bojan

Definitely useful !!!
You just have to find (or someone should make it for you) the suitable worm (screw) with the same pitch (modulus) and you are in business !
A bit of diamond paste used to polish the worm gear after the assembly would make it perfect.

I thought it might be, now my mind has something else to ponder!

Not being an engineer I'm not sure about pitch/modulus etc., but laying a plastic ruler over the threads reveals that every tooth is exactly 2mm apart.
Maybe a piece of brass threaded rod with the right pitch could be pressed into service as a worm?

The wife has just got back from shopping, with some Brasso, so I've got work to do!

Diamond paste? haven't heard of that...

Thanks Bojan

Chris

[bojan]

Something like this:
http://www.ebay.com.au/itm/1-pc-5-gr...item6420b579a5

Yes, 2mm pitch threaded rod may be OK as a worm, but you still need it machined to fit bearings and timing pulley (or gear) to drive it.