"alabbe0405" wrote in message able.rogers.com...
Hi, I'm trying to cut a piece of brass threaded rod in two to use the halves
as racks for focussing a view camera. Now I can cut it no problem with a
slitting saw, but my problem is that is then starts doing some interesting
contorsion and looks like a spiral or some kind of randomly generated
curve... I presume that internal stress are released by the cutting and
causes the deformation to occur (also so it just cutting a piece from a flat
bar of brass, 3/16 thick, quite surprising to see the piece your cutting off
take a 1/8 inch curve in about 5 inch of lenght...). So my question is for
all the saavy people out there, can I and how do I relieve the stress to
prevent (or at least reduce) the deformation caused by machining.

(yes I know I could probably buy the racks but considering the price of
threaded rod vs the price of racks....)

Thanks all for you help.

Alain Labbe

Is this pre-threaded rod that you bought or something you've die-cut
yourself? Stuff from the hardware store is probably roll-threaded and
will have a lot of stress in it which would lead to the pretzels
you've got. Heat it up to anneal it, won't take much and it doesn't
need to be quenched.

If you want to avoid racks, why not design something like a
quick-release nut for your threaded rod to hook your front standard
on, then use the quick release to do the rough focusing and provide
your threaded rod with a knob to turn it for the fine focus.
Something similar, but much smaller, can be seen on some Lyman
aperture rifle sights.

Stan