"Jim" wrote in message
m...
I have two pieces that will eventually be chromed. One will be held
via a shoulder bolt and the other will have pressed in bushings.
Neither piece spins. they must rock back and forth at low speed and
very light load. Should I allow for chroming when I ream the holes or
ream them afterward. If afterward - how much material should I leave
or should I ream them to size and then ream them again after chroming.

Thanks
Jim

You didn't specify if your chrome was ornamental or hard chrome, so I'll
assume you mean ornamental. If you request it, they can mask off the area
of concern so it doesn't receive any plating. I am of the opinion that
would be in your best interest. Once you get parts chromed, you risk
damaging them in handling if you do any kind of operation on the machines.
Further, if you screw up and scrap them, you're out the chroming costs along
with the loss of the part.

If, by chance, you find that you still want to ream your holes after
plating, anything from a couple thou up to no more than .015" should be
enough, depending on the condition of the hole you've created. Reaming any
more than .015" can get testy, especially in small holes. I suggest you
double drill your holes so the end result is cleaner and more likely to be
the size you want. Start with a drill that is a couple sizes smaller for
the first drilling.

Hard chroming would not leave you any options, you could not do the work
afterwards unless you have access to grinding equipment. Chrome (hard
chrome) can not be machined. You would have to mask finished diameters.

Harold