Re: [CAD_CAM_EDM_DRO] Re: Creating long straight edges (and big squares)

Dave, the Y axis on my big machine was done similar
to your description. Here the bolting surface for the rails
are the centerline of 4"x6"x1/4" steel tubing. Along that
centerline the 1/4" face of the tubing is fairly flexible
so 3"x6"x.375 ground steel pads are attached to it.
The rail is bolted to the pads, with the bolts going
all the way through the tubing wall.

Now to put this row of pads on I first epoxied 3
little copper nibs where each would go on the tubing.
They were just .05 or so high flat copper rivet heads
cut off and glued upside down.

Now I laid the pads on the copper nibs, so it is kinematic.
It doesn't rock. Using the same level technique as the write
up I just filed the copper nibs for each pad until they were
all level and in the same plane. I also used an indicator
to check from one to the next.

Once that was done I simply applied some epoxy putty
to the pads and lightly clamped each one. The pads still
rest on the nibs, but the putty fills in the rest of the space.
When hardened I have a very flat mounting surface that also
stiffens up the tubing face. It supplies some constrained layer
damping as well.

This method is pretty quick.

There are pictures on the web site but it is still down. ISP
tried switching to windows 2000 server software and it
isn't going so well.

Les

Leslie Watts
L M Watts Furniture
Tiger, Georgia USA
http://www.rabun.net/~leswatts/wattsfurniturewp.html
engineering page:
http://www.rabun.net/~leswatts/shop.html

----- Original Message -----
From: "turbulatordude" <davemucha@...>
To: <CAD_CAM_EDM_DRO@yahoogroups.com>
Sent: Saturday, July 06, 2002 10:09 AM
Subject: [CAD_CAM_EDM_DRO] Re: Creating long straight edges (and big
squares)


> Hi Les,
>
> Very well written and very clear. It comes at a great time for me.I
> think I am going ahead with 3" square tubing for the table and plan
> on mounting rails to that. I had given thought to using the table
> as the rails, and just run bearings on that. Seems to get it level
> is one thing, to get it flat is another, and to get two sides flat
> and perpendicular would be prohibitivly hard with hand tools.
>
>
> When thinking about how to do it faster, easier, better, or some way
> change it, I thought about making a beam of some sort with screw
> adjustments. Then bolting on the linear rails one would be using
> anyway. Then with your measurement technique, one could run an
> indicator up and down the length of the part to be straightened.
>
> Seems the jig would cut a lot of time off and be worth the effort.
>
> Even seems that one could use that jig for a finish grind of a few
> tenths to get the whole length with a even finish.
>
> Dave
>
> ps: This sentence could be mis-leading to a novice.
>
> >Sometimes I grind an area that feels high with the plate.
>
> This is about halfway down, immeadiatly before "A note about
> grignding technique..."