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Old May 17th 06, 12:47 AM posted to rec.radio.amateur.antenna
Dave
 
Posts: n/a
Default mechanical question, aluminum swaged joints

diameter tolerance is what i am looking for. this is an antenna element
joint with 2 through bolts in the swaged area, no slitting. measured
diameters are 1.252 OD for the inner piece and 1.264-1.277" ID for the
swaged section, slightly out of round because of the 2 bolts flattening it a
bit. the bolts are vertical and when tightened 'normally' which causes a
bit of flattening, the element can move horizontally quite a bit. any
recommendations for improvements?? adding horizontal bolts? shims? any
portable tools to swage something that big, or is that a machine shop only
type of job?

wrote in message
oups.com...
Diameter tolerance or out of round? It's probably not too big of a
deal for most applications especially if you're going to split/slit and
clamp it.

You're probably better off erring on the side of slight interference if
you're splitting and clamping and adjustability is not very important.

If you're looking to make a sliding adjustable joint, I'd keep a nice
tight tolerance, maybe no more than a few thousandths of an inch if you
can do so. If you can't, it's not a big deal, but a good mechanical
fit will allow sliding while still giving lots of strength.

If you make the fit loose (10 thousandths) you're going to be relying
on your hose clamps or bolts to do all the holding and you're probably
going to really only get contact under the clamping points, which is OK
in a lot of applications. A better fit will spread out the clamping
force more.

73,
Dan
N3OX