On 2010-12-28, Karl Townsend wrote:
On Tue, 28 Dec 2010 11:54:44 -0500, "Tom Gardner"
wrote:


"Karl Townsend" wrote in message
. ..
On Tue, 28 Dec 2010 00:04:37 -0600, Ignoramus7943
wrote:

Karl, I wanted to ask a question about manufacturing methods for the
Ar-15 receiver.

Look at this:

http://www.cncguns.com/projects/ar15lower.html

He had to reclamp his piece numerous times to make it on a CNC mill. I
wonder, how much of that is due to lack of the 4th axis.

My feeling on this is that with a suitable 4th axis, this receiver could
be
done in 2-3 reclampings, or perhaps even one. With a 4th axis, clamp
once, and then turn various sides towards the spindle to be machined.

Am I making any sense?

i
I had not seen this site, thanks.

You have a valid point, but you lose so much rigidity that your
machining speeds would be killed.

Most parts are manufactured with a real eye on fixturing. That is ways
to quickly remount the part for the next operation. With a good
fixture design, you can go from one op to the next in a few seconds.

I had not seen this website, thanks for the link.

I have prints for various fixtures, do you want me to root them out? I had
wanted to do what you're contemplating but my mill is stuffed for the next
year. The company's projects are piled up, I have a machinist working 'till
9:00 PM every night...no room for personal stuff.

Most certainly, I'd appreciate it.

Creeping elegance is setting it, I was going to get an 80% lower, then
saw the forging. So, I asked the kid to program it. Now he wants to
build directly from billet and do both .223 and .308. He just called
over lunch and and wants the old wire EDM up and running to wire out
the mag pocket.

I sent him the site Iggy found for machine from billet and told him it
looked a bit much. The kid says that guy don't have production
experience and he can do better.

The only tooling we don't have is a 1 3/16 by 16 tap. Its $160 from
MSC, ouch.

Karl

Karl, how many hours of your or your son's labor it will take?

i