[modeleng] Merry Bah Humbug ....also Help re: Crawford Multibore...
- From: "Chris Crosskey" <chris.crosskey@xxxxxxxxx>
- To: <modeleng@xxxxxxxxxxxxx>
- Date: Mon, 24 Dec 2007 09:31:38 -0000
Merry Bah Humbug to you all!.....
...Help!!...
I've got a lever-operated Crawford Rapidgrip multibore that was in a
less than wonderful condition when I got it... I stripped it down and
realised that it had probably been taken apart and put together again by
someone that didn't understand the concept of how they work.... Now I'm
not sure if I know myself because, try as I might, I can't get the lever
to function.
In theory it's pretty simple, the collets are closed by the sleeve in
which they sit moving forward slightly and pushing them into the nose
... this is accomplished by means of six balls being pushed down against
a sloped section on the outside of the collet sleeve, combined with the
fact that as the ring on the lever which acts against them moves back,
the balls will revolve in the right direction to push forwards. There
are three small spring-loaded bits incorporated in the collet sleeve to
act as a return/release mechanism and threaded onto the back of the
collet sleeve is a geared piece that allows for overall adjustment of
the setting of the collet.....
I found that one of the sprung pieces had been broken (the spring had
been anyway) so fashioned a repair for that, the other two had their
retaining pins pushing against the springs rather than in front of the
pushing ends and that got corrected on reassembly.... Had some problems
getting the actuating ring back over the balls on reassembly but ended
up realising you do it with the collet sleeve as far forward as the
geared adjuster will manage and to do that you take the retaining
screw-pins (they're like grub screws with the ends machined down a bit)
out of the release spring bits (see above) and put them back once the
actuating ring is in place.....
My problem is that the lever isn't seeming to work, it would appear
jammed, however the geared-adjuster is working fine and I can move the
collet sleeve around inside the chuck using it .... What should I be
looking to do .... I really need this chuck in action as I've got a
repetition job coming through that will be a nightmare to deal with in a
three jaw......
Thanks for any help you can be and all advice...... if anyone's got a
service manual for one of these things I could obtain a copy of I would
be very very grateful
Chris C
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