Re: Southbend 9" lathe table in CONCRETE?


Roger Bickers
 


That park bench isnt a typical concrete mix design for one, nor does it carry a constant live load, that also has to endure prolong periods of vibrations.  Place a vial of mercury on your lathe bench and watch it quiver. Now think of what concrete is made from and how it works. While concrete has compressive strength, it hardly has any tinsel strength...and that compressive strength is highly influenced by the materials under it. ...take those out, suspend it, and now you have something like a hard rubber band.
Concretes science, chemistry,  physics and a ton of variables. For ya'lls little lathes, stick to cast iron, heavy ga. sheetmetal or hardwood for benches. 

On Sat, Dec 28, 2019 at 10:03 PM, Nelson Collar via Groups.Io
<nel2lar@...> wrote:
Bill
I think I would set it on 3/4 inch treated plywood at least the size of the legs, maybe a double layer. This way it will absorb any vibration from the machine and the footprint will be distributed over a greater area. Maybe I will look for legs for my lathe and get it off the bench. I have gotten to the point I hate horizontal surfaces. They tend to be catch it all's. 
Happy and Healthy New Year to All.
Nelson Collar

On Saturday, December 28, 2019, 08:29:13 PM CST, Bill in OKC too via Groups.Io <wmrmeyers@...> wrote:


Mine is a restoration project, sitting on the floor in front of the stand that came with it. Shipping weight for the lathe is 1060lbs, and the stand ships separately. They're another couple or three hundred pounds depending on if they're cast iron, or tubular steel, as mine is. My floor is a very thin slab of concrete. The workshop was a back porch step, then a patio floor, on grade level and with little or no rebar. About 3" thick or so. That's one of the reasons I'm not looking for any larger machines. I don't think the floor would support them. Someone before I got here enclosed it, but didn't put rebar in and pour more concrete, or replace what was there with a real slab.

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 Saturday, December 28, 2019, 7:26:35 PM CST, Nelson Collar via Groups.Io <nel2lar@...> wrote:


Bill
I am kind of lost, you have a 10L. Is it on a stand or mounted to a bench? I have a 10K and it is mounted on a bench on a concrete floor. The concrete had been there for over 20 years and has no cracks yet but if I had a large machine with a lot of vibration I would expect to see cracks. By the way what kind of a floor do you have?
Nelson 

On Saturday, December 28, 2019, 07:15:32 PM CST, Bill in OKC too via Groups.Io <wmrmeyers@...> wrote:


They don't usually have a thousand pounds of stuff mounted to them, either. I don't know offhand what a 9" A or C weighs, but my 10L is around a thousand pounds. And I don't think that includes the stand, which I wouldn't need if I had it on a concrete bench.

SWMBO and I are considering a move, so I don't think a ton or so of concrete bench is a good idea. Not yet, any way! ;) Not to mention that I'm no expert concrete worker. I also wonder how much it would cost to make one out of non-shrinking grout. A bunch, I bet!

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 Saturday, December 28, 2019, 6:59:34 PM CST, mike allen <animal@...> wrote:


        but ya just have to remember 1 thing & this is a direct quote from a but that owns a concrete outfit " it's concrete, its gonna crack !!"

        animal

On 12/28/2019 4:44 PM, Nelson Collar via Groups.Io wrote:
Roger 
I do not understand all the noise about concrete. Look at a concrete park bench, usually over 4 foot and I have never found one to sag. And they are not that thick! 
Nelson

On Saturday, December 28, 2019, 08:54:54 AM CST, Roger Bickers via Groups.Io <mr.concrete1964@...> wrote:


A top limited to 3.5" will fail even with rebar. Your top should be at least 6" and would need a double matt of #4 rebar or else the top will sag and flex. 
Youd also need corner bars with 18" tails to join the top and legs together on the end of each matt.
The legs should be 2/3 of the overall size of the top in width to provide sound bearing and support, though I would definitely recommend a rebar cage here also.  

Sounds like overkill to ya? It's not. 

Oh and you'll still have to shim/ level the machine.

Do bother placing your cast iron lathe on aluminum either.. they'll fuse together.

Roger


On Fri, Dec 27, 2019 at 3:53 PM, ww_big_al

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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