RE: [CAD_CAM_EDM_DRO] Rifle stock

Basically, the 4th axis is a rotary table mounted on its side (generally
along the long axis of the machine) One end of the part is chucked in the
rotary table and the other end is chucked ina a freely rotation bearing of
some sort. This actually uses 3 axii as the Y axis is shut off and the
rotary axis turned on.

With this sort of set up, you would use the Z axis, the X axis and the
rotary axis. The Y axis is not needed or used. You could make a rifle
stock in this fashion by taking a cut along the X axis changing the Z axis
position as the machine moved. At the end of the cut, rotate the rotary
axis some amount and take another X axis cut.

R. Wink



_____

From: CAD_CAM_EDM_DRO@yahoogroups.com
[mailto:CAD_CAM_EDM_DRO@yahoogroups.com] On Behalf Of dannym@...
Sent: Saturday, February 02, 2008 10:05 PM
To: CAD_CAM_EDM_DRO@yahoogroups.com
Subject: [CAD_CAM_EDM_DRO] Rifle stock



I gotta thank you guys for answering my starter questions about CNC milling.
You guys are the best!

OK, next question. Say I'm building a crossbow with a rifle-type stock, say
32" long, with some nice complex curves and I have a Taig. This is way
beyond the handling capacity of the table. In fact the whole thing sounds
like I would do best with a 4th axis anyways not just putting it flat on the
table on its side. But even still, it's far too long.

Well first question is, I assume that even if this were something that fit
on the table wouldn't we have 2 holders, one the powered 4th axis the other
a free-rotating clamp? What is such a thing called, or do we just buy a
cheap rotary table and remove the gears so it turns freely?

Actually I could see extending the table with some sort of holder to attach
the free-rotating clamp off to the side with like a board clamped to the
Taig's table. I later realized the rotary 4th axis clamp need not be
directly clamped to the table either. Even still, this would require 3,
maybe 4 runs due to the Taig's limits on X-distance.

Any comments? Is the idea sane at all, or should I limit myself to doing
3-axis milling with the work on its side? I suppose for the most part that
would work. The trigger cavity and the track couldn't be carved in the same
steps and there are limits to the features which could be carved into the
edges, but then you don't always get what you want.

How much of a pain-in-the--ass is it to work with 6 different runs (3 per
side) with the stock removed and re-clamped, re-aligned, but offset 12" each
time to expose another area for milling? Would say BobCAD work with this
plan or make it really really hard?

Danny




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