Re: Clamping Fixture

Hello,

FWIW, You won't actually have anywhere near 127 pounds of downward
clamping force; see my post at DIY-CNC for details...

AND... Although that flycutter "scares you", it is a FAR better way
to surface material on your sherline mill than using a 3/8 endmill!

It will use less force, be more likely to be flat, look better, and
take FAR less time. Lower cost likely too!

AND, as mentioned in my post over there; the flycutter is much more
compatible with a vacuum clamping strategy than will an endmill.

I also posted a few other alternatives to vacuum; just in case<G>

BTW, Learn to love your flycutter; it's a VERY good thing with a
mill. ESPECIALLY a small mill like a Sherline!

Hope this helps,

Ballendo

--- In CAD_CAM_EDM_DRO@yahoogroups.com, "Victor A. Estes"
<vestes@...> wrote:

>
> 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
>
>
>
>
> [Non-text portions of this message have been removed]
>