Re: Southbend 9" lathe table in CONCRETE?


eddie.draper@btinternet.com
 

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.

Eddie

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.)


A human being should be able to change a diaper, plan an invasion,
butcher a hog, conn a ship, design a building, write a sonnet, balance
accounts, build a wall, set a bone, comfort the dying, take orders,
give orders, cooperate, act alone, solve equations, analyze a new
problem, pitch manure, program a computer, cook a tasty meal, fight
efficiently, die gallantly. Specialization is for insects.
LAZARUS LONG (Robert A. Heinlein)





On Friday, December 27, 2019, 09:38:15 PM CST, Vince Beachy <vincebeachy@...> wrote:


Hey everyone,

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?

Vince

On Fri, Dec 27, 2019, 9:48 PM Bill in OKC too via Groups.Io <wmrmeyers=yahoo.com@groups.io> wrote:
You ain't kidding! Though you could put shelves between the columns. I've seen a photo of one that was cast in one piece, similar to the one Carla described in the PM link someone posted earlier, and it just had a depression for a toe-kick, with maybe a bit of room for knees, too. Probably at least half again as much concrete as the one with the Atlas lathe on it. I'm thinking something like that would run close to half a ton by it's lonesome. I though I had a photo of that, but can't find it. If I ever do, I'll send it to the group. I've been looking for it for years. 

William R. Meyers, MSgt, USAF(Ret.)


A human being should be able to change a diaper, plan an invasion,
butcher a hog, conn a ship, design a building, write a sonnet, balance
accounts, build a wall, set a bone, comfort the dying, take orders,
give orders, cooperate, act alone, solve equations, analyze a new
problem, pitch manure, program a computer, cook a tasty meal, fight
efficiently, die gallantly. Specialization is for insects.
LAZARUS LONG (Robert A. Heinlein)





On Friday, December 27, 2019, 07:46:32 PM CST, harry molwitz <harry.molwitz@...> wrote:


Might be tough to move around the shop, I would be certain of the positioning. It also seems to limit storage underneath.

Harry

On Fri, Dec 27, 2019, 6:11 PM Bill in OKC too via Groups.Io <wmrmeyers=yahoo.com@groups.io> wrote:
It would be interesting to test and see what difference, if any, it made in the accuracy of the lathe. 

Bill in OKC

William R. Meyers, MSgt, USAF(Ret.)


A human being should be able to change a diaper, plan an invasion,
butcher a hog, conn a ship, design a building, write a sonnet, balance
accounts, build a wall, set a bone, comfort the dying, take orders,
give orders, cooperate, act alone, solve equations, analyze a new
problem, pitch manure, program a computer, cook a tasty meal, fight
efficiently, die gallantly. Specialization is for insects.
LAZARUS LONG (Robert A. Heinlein)





On Friday, December 27, 2019, 04:17:08 PM CST, Steven H via Groups.Io <stevesmachining=aol.com@groups.io> wrote:


Here is a photo of what appears to be a concrete lathe bench with an Atlas-Craftsman lathe on top. Not my lathe, just a photo I found on-line some time back. Personally I think it's overkill. But concrete is relatively inexpensive so knock yourself out should you choose to go this route. Good luck.

Regards,
Steven R. Haskell
 

-----Original Message-----
From: ww_big_al <arknack@...>
To: SouthBendLathe <SouthBendLathe@groups.io>
Sent: Fri, Dec 27, 2019 3:53 pm
Subject: Re: [SouthBendLathe] Southbend 9" lathe table in CONCRETE?

I don’t know about a lathe table, but I do fill my grinder pedestal stands with either concrete or sand. That dampen vibrations a lot.
Al
 
From: SouthBendLathe@groups.io <SouthBendLathe@groups.io> On Behalf Of Steven Schlegel
Sent: Friday, December 27, 2019 11:12 AM
To: SouthBendLathe@groups.io
Subject: [SouthBendLathe] Southbend 9" lathe table in CONCRETE?
 
With all of the discussions about lathe tables, I have to ask:  What is your opinion about making one out of concrete?  I have heard they are very dead (no spring) so makes turning a lot easier.  As I approach putting my 1940 SB 9” A and C lathes into operation, I am planning ahead for the tables.
 
Steven

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