Anodising a worm wheel

[Gvarouha]

G'day,

I'm making a worm gear set and am wandering if anodising the wheel after lapping will have an impact on the accuracy of the lapped surface.

Also am I best to use brass or stainless steel for the worm itself.

Cheers- George

[torana68]

these guys use stainless/aluminium :
http://www.yaloastronomia.com/instruments/mounts/gem-1/

Anodising has an added thickness but you should probably ask whoever is doing the Anodising

[Gary47]

Anodizing will add to the surface of the aluminium but only a maximum of a couple of microns. Depends on the anodizing current and time for the process.
Opposed to this is the fact that the preparatory process (acid dip) can remove material.
It often evens out. However of greater concern is the difficulty of getting an even coating on the part. With a complex shape it is more difficult to get an even coating and on sharp corners you usually get no coating at all.
Definitely talk to the people who are going to do the job and make sure they understand your requirements.
If they don't sound confident that they can do it to your standards look for someone else.
Gary

[jenchris]

Use phosphor bronze. It is a lot less prone to wear and has self lubricating properties

[bojan]

The problem with anodizing the wheel, apart from adding material in not well controlled process (after lapping, which is well -controlled) is the hardness of the surface.
I suspect the result will be accelerated wear of the worm.
The best combination is bronze for wheel, stainless (hardened, then lapped if you want) for worm.

[jenchris]

I would only recommend a brass wheel if it was continuously revolving. When it is often only a section being used, you get sector wear which can result in pec being similarly sectorised.