Re: [CAD_CAM_EDM_DRO] Table Construction

In a message dated 7/8/2003 12:30:29 AM Central Standard Time,
mds1878@... writes:

> My question on table building is do I need to floor anchor the table?
> Likely I will use 3" square steel tubing for stand
> construction.

Ken: What, you gonna weld-up a stand of 3x3x1/8 or 3/16" tube? I assume you
would then have four of those as legs. I suggest you weld 3/16" or 1/4"
plates about 3.5-4" square to the bottom ends of those legs, and maybe find an
old auto-tire with SOME tread left, and cut four squares of that tread to make
"feet" to go under those square "leg-ends". I suggest you drill whatever
suitable holes around the "rim" of those squares, and fasten on the rubber feet
using fasteners and washers in the tread-valleys, threaded into those
end-squares. That will just-slightly "pad" the machine from the concrete, and give you
sufficient friction that it will not slide easily, but, hey, a machine with
THAT total weight (probably 350 lb. when you are done?) is not going to waltz
about with only a quill-head moving around! If it actually does, then you
probably have your coordinate-accel./decel. rates much too "sharp". Increase the
time to accel./decel. 20%, and try some more. The "slow-down" will be hardly
noticeable, except that the machine will not be "jiggled to death"!

If such a machine's movement were SO severe that fixing to the floor were
necessary, then it is likely "dry, afterthought" hardware such as expansive
(lead-sheathed?) nuts, etc., might well not be sufficiently permanent to survive
more than a few weeks, if that! You'd need "cast-in J-bolts" or something like
that, and LOCATING such precisely during the concrete-pour can be very
cumbersome! A professional machinist (job-shop owner) helped me "set down" my new
Bridgeport 15 years back, and in the conversation as we worked, he said he had
NO idea why BP cast-in drilled bosses for mouting-bolts in the heavy cast-iron
machine-base, as in all the 30 years HIS machine-shop had been in business
with dozens of mills and lathes, he had NEVER found a situation where bolting a
machine to the concrete floor was necessary!

Just build it "square", seal-weld the joints, grind 'em a bit, smear-on some
Bondo, sand flat, prime, paint it so it looks like the doors on a new Fridge,
mutter some Haiku about the proper order of things in nature as you work
(English translations will work OK), and all will be fine!

Jan Rowland


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