[Gigas]

I want to have a couple of aluminum parts anodised black. (They are raw now)
On each part, there is a hole with threads where a bolt goes.
Will the anodising affect those threads at all?

The anodiser said that during the process, they put the parts into sodium that will "reduce" a tiny bit of metal and that this will affect the threads making them a little loose... :O
This "lost" metal is nothing to be seen on the flat surfaces of the parts but since the threads are more sensitive, there will be a noticeable difference, there....

Is he bullshiting me or is he right?

 

[Aredubu]

I'll bet money that our KAD upper triples clamps, those with the hole and threads for the dampers have the same thread sizes, whether the triples are raw or anodized. There might be some metal loss, but I would think it is pretty minimal.

 

[Gigas]

I'll bet money that our KAD upper triples clamps, those with the hole and threads for the dampers have the same thread sizes, whether the triples are raw or anodized. There might be some metal loss, but I would think it is pretty minimal.

That was the first thing coming into my mind when I tried to find an example of an item being anodised and having a hole...

The parts I want to anodise are those two brackets

So I guess it will be safe to do it.....

 

[Rifleman]

I had the aluminum clutch cover rings anodized...

They have a cross hatch pattern on the surface put in with a 320 grit wet sand...

the cross hatch was visible after anodizing... the amount of surface that changes is quite minimal. I wouldn't think it would be a problem.

the surface removed, and the surface added should be about the same. Most threads are cut with 75% thread engagement (that means that there is 25% empty space) so some slop in the threads is standard.

 

[n2wheelies]

hard anodizing will affect tolerances, in general regular anodizing is fine wrt threads...

 

[Gigas]

hard anodizing will affect tolerances, in general regular anodizing is fine wrt threads...

Hmmm... Now that's a new thing coming...
What's the difference between hard and regular ano?

Edited a few minutes later....
Never mind.. found a bit of info here....
http://www.wisegeek.com/what-is-hard-anodizing.htm

Thanks