Re: Southbend 9" lathe table in CONCRETE?
I was thinking of a top about 3 in thick. It would be made with forms made from plastic laminated mdf. Holes would be drilled and nuts buried in place for mounting. I figure about 300 lbs of concrete. The base could be made of angle iron. Wood would work, too, but would need to be hefty. The forms would be removed after the concrete set up. The concrete could be finished if needed. Shims would be used under the lathe bed legs to remove any bed twist. A three leg setup could be used to eliminate any twist from an uneven floor. With a steel angle iron frame and legs there should be lots of room for shelves and storage under it. Moving it would be a bigger, but it is for most lathes.
I'm traveling, so please excuse any typing errors.
From: SouthBendLathe@groups.io <SouthBendLathe@groups.io> on behalf of eddie.draper@... via Groups.Io <eddie.draper@...>
Sent: Friday, December 27, 2019 11:44:48 PM
To: email@example.com <firstname.lastname@example.org>; SouthBendLathe@groups.io <SouthBendLathe@groups.io>
Subject: Re: [SouthBendLathe] Southbend 9" lathe table in CONCRETE?
My 3 pennorth on lathe supports and foundations:
What matters most are rigidity, stability of dimensions and damping. If any of those are already inbuilt in excess into the machine tool, then the other 2 in the support system can be reduced. Thus, a substantial lathe can be mounted in a ship without its mountings being substantial.
If the lathe (etc.) has to be forced into shape because it is a bit twisted, you need a mounting that is TORSIONALLY stiff. A single flat plate of anything has minimal torsional stiffness. A single large hollow section is medium good, but would be much better with internal diagonal braces. They don't need to be especially heavy. You will note that the best lathes have diagonals cast into the bed structure. Thick solid stuff (pretty well anything) is good because it naturally includes the diagonal bracing, and you will note that the concrete bench recenty illustrated has great thickness. Torsional stiffness is also good for resisting cutting forces.
Stability comes from 3 issues, namely external inputs, temperature change and humidity change. For example wood is very stable wrt temperature, but goes all over the place with humidity. Different metals have different coefficients of expansion, ferrous being lower than non- ferrous (as a sweeping generality) and would match the lathe metal better.
Damping is inherent in some materilas and not others. The simple test is whether you can make a good bell from it!
Finally, note that the stiffness of the job itself has great influence on the tendency to vibrate.
On Saturday, 28 December 2019, 04:35:37 GMT, Bill in OKC too via Groups.Io <wmrmeyers@...> wrote:
What Allan said. ;) Epoxy floor coating would probably work fine for a sealant. Maybe even Thompson's Water Seal. Let me know how it works out!
Bill in OKC
William R. Meyers, MSgt, USAF(Ret.)
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efficiently, die gallantly. Specialization is for insects.
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On Friday, December 27, 2019, 09:38:15 PM CST, Vince Beachy <vincebeachy@...> wrote:
New guy here, with some thoughts. I really like this idea as I have some experience in tying rebar together and making forms.
If you were to put some sealer on the top and have some channels/gutters could you also make a coolant system built into it? Thoughts?
On Fri, Dec 27, 2019, 9:48 PM Bill in OKC too via Groups.Io <email@example.com> wrote: