On Mon, 7 May 2012 21:41:47 -0400
"Machinist60" wrote:

big snip
Many thanks for your reply Leon. I had checked a little but am not as good
at finding stuff as you are.

Patents US693256 and US701195 appear to describe this tool pretty closely.
You are right I think about the minor mods to save cost or manufacturing
time. My chuck is definitely one piece (F & C). I did think screw may be
left handed but I see nothing in the patent to indicate this but it would
make sense. I thought this screw may have been a riveted nut from its
appearance but I now think its more likely that the centre of its head has
been damaged by someone try to remove it or by tools slipping in the chuck.
My next step is to apply heat, but not so much as to spoil the springs G and
make/modify a common screwdriver that will fit inside the chuck.

Hi John,

Just got lucky finding the patent, I've learned some too searching for
"What is it?" items...

I tend to agree with Don's thought that a left hand thread isn't needed
there. But I've been burned too many times with them not keep that
possibility in mind.

You may be able to use a 1/4 inch insert bit for that screw. Carefully
grind it down to fit nice and snug. Another thought is to try using one
of the hand impact wrenches with said bit. Like one of these:

http://www.harborfreight.com/impact-...ase-37530.html

I would try clamping the spiral and lower part of the chuck between
something like 2x4's in a large vice and then try the impact
screwdriver if you can't budge it by hand.

Good luck!

--
Leon Fisk
Grand Rapids MI/Zone 5b
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