Re: [CAD_CAM_EDM_DRO] Clamping Fixture

Jon,

Very good point about the vise, unfortunately I do not have a milling vise that opens to 2 1/2". I have the Sherline vise and it just does not open wide enough. 127 lbs does not sound like a lot of holding power, and that is what I was concerned about.

I'm going to use a 3/8" dia end mill. I've tried the fly cutter and I just don't like that thing swinging around, it scares me.

Thanks,

Victor A.

----- Original Message -----
From: Jon Elson
To: CAD_CAM_EDM_DRO@yahoogroups.com
Sent: Wednesday, March 07, 2007 11:33 AM
Subject: Re: [CAD_CAM_EDM_DRO] Clamping Fixture


Victor A. Estes wrote:

>Hi, has anyone built a vacuum table for a CNC mill? I need to clamp some aluminum plates (2 1/2" wide x 3 1/2" long x 1/2" and 1/4" thick) flat to the milling table so that I can surface the top of the plates. This is not a one time operation, but rather something that I will need to do all of the time. I was thinking that a vacuum table might do the trick, what do you think? Any suggestions. This will need to fit a Sherline metric CNC mill. I figure I can scale something up or down to fit.
>
>
>
Assuming a rectangle, that is 8.75 in squared, and the holding power of
a hard vacuum will be
127 Lbs. That may work for light milling, but it is a bit iffy. If the
vacuum is much weaker
than 28 In Hg, I don't think it has a chance of working. Why not just
put it in a vise with
parallels under the object? That's what I do. No way is the piece
going to fly off the vise
jaws. If you use a flycutter with your vacuum table, there is a good
possibility it could fling
a full pound "bullet" at you!

Jon




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