I have some beginner questions about leveling machines. When you use feet
or something like that you are sending all of the weight to the point
where the feet attach to the machine. Does that stress the machine
because you're grately decreasing the surface in contact with the floor,
from the whole base of the casting to the small area the top of the foot
makes contact with the machine? Do I need to grout the area between the
rest of the casting and the floor?

Also, I have some levelers that use a sliding wedge with a horizontal
screw to go up. My thought was that I'd have a bolt anchored into the
concrete, put the leveling pad on, then the machine and a nut to draw the
machine down to the leveling pad. That way the machine could not go up or
down. I'm in earthquake country and I don't want a top heavy thing
tipping over.

I understand those solid mounts won't provide any vibration isolation.

Thanks.

Lets see now, a leveling screw or just set it on the concrete will cause
stress? There is no possibility of the foot of the machine ending up with
all of its metal in firm contact with the concrete as this is a physical
impossibility! No way that the concrete will match the flat of the foot so
there will only be one little part of the foot touching the concrete anyway.
Since the machine is sitting on its 4 feet and the concrete isn't flat
enough to keep all 4 feet exactly on the concrete, an unleveled machine will
indeed be stressed in some way. Using leveling bolts and so forth will
provide an equal force on each of the feet so that the machine will be
sitting level and even. IN addition, if you attach the leveling mechanism
to the floor, the machine will tend to not dance about the shop when an
earthquake happens.

--
Bob May
Losing weight is easy! If you ever want to lose weight, eat and drink less.
Works every time it is tried!

Bob May wrote:

snipped

Since the machine is sitting on its 4 feet and the concrete isn't flat
enough to keep all 4 feet exactly on the concrete, an unleveled machine will
indeed be stressed in some way.

Not to disagree with you, because you are certainly correct in any
general practical sense, but:

It was only a few years ago I learned that you can get the legs of a
four legged stool to all contact an uneven floor and eliminate all
wobble simply by rotating the stool around it's central axis. You'll
find the spot where all four legs are touching within a quarter of a turn.

This works with considerable amounts of waviness of the floor, providing
of course there are no step discontinuities.

The proof of why this works isn't very intuitive, but with a little
thought you'll understand why it must be so.

I've found this trick works pretty well with rectangular four legged
tables too.

If you don't believe it, try it yourself.

Jeff



--

Jeff Wisnia (W1BSV + Brass Rat '57 EE)

"If you can smile when things are going wrong, you've thought of someone
to blame it on."

In article , Jeff Wisnia says...

It was only a few years ago I learned that you can get the legs of a
four legged stool to all contact an uneven floor and eliminate all
wobble simply by rotating the stool around it's central axis. You'll
find the spot where all four legs are touching within a quarter of a turn.

Of course this doesn't work if the floor is flat, and the
stool has unequal legs!

Jim

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JRR(zero) at yktvmv (dot) vnet (dot) ibm (dot) com
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On Thu, 01 Apr 2004 00:06:48 +0000, Philippe Habib wrote:

I have some beginner questions about leveling machines. When you use feet
or something like that you are sending all of the weight to the point
where the feet attach to the machine. Does that stress the machine
because you're grately decreasing the surface in contact with the floor,
from the whole base of the casting to the small area the top of the foot
makes contact with the machine? Do I need to grout the area between the
rest of the casting and the floor?

I have a lathe which has a base made of ~ 3/16" steel plate (factory made).
The feet of the lathe are steel plates which extend down a few inches and
are bent at 90 degree angles to provide a contact surface with the floor.
Holes in this section of the feet allow the machine to bolted to the floor.
In order to level the machine I got some short lengths of 1" threaded rod,
nuts and washers to use as screw jacks in the holes in the feet.

Now that they are installed the lathe is very "springy". Not what I wanted
at all. The reason for this is that with the leveling screws in place the
feet no longer make full contact with the floor. The contact point of the
feet has been reduced to the 1" diameter area of the screw underneath it,
which allows the feet to flex.

Also, I have some levelers that use a sliding wedge with a horizontal
screw to go up. My thought was that I'd have a bolt anchored into the
concrete, put the leveling pad on, then the machine and a nut to draw the
machine down to the leveling pad. That way the machine could not go up or
down. I'm in earthquake country and I don't want a top heavy thing
tipping over.

This sounds like a better solution, although I haven't tried it yet. I don't
think it would be very difficult to machine up some wedge type levelers,
but I haven't had the time to do it.

I understand those solid mounts won't provide any vibration isolation.

No, I don't think they would if they are just solid steel.

--
"Please God, help me cleanse the computer of viruses and evil photographs
that disturb and ruin my work ..., so that I shall be able to cleanse
myself." -- Rabbi Shlomo Eliahu



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1'm sorry, but I thought that was for Three-legged items, not Four?

--
Peter DiVergilio
A bumble bee is faster than a John Deere tractor.