More lathe bench questions

[SteveM]

I've settled on making the top out of 4x4's.

We have a neighbor who is a flat-bed trucker and the loads are routinely put on 4x4's, and they don't re-use them.

They are all about as straight or straighter than I can buy at the home center stores, and they are not all dented up from the loads.

I have a few questions.

I figure I'll drill three holes (left, right and center) in each and use all-thread with nuts and washers on the ends to hold it all together. The bench my Atlas was on was done that way (and it was only a 2" top).

Should I also glue them together? I'm not sure there's a downside to that, but just wanted to check if anyone has any ideas.

What should I use to finish the top?

I know that certain finishes would be attacked by the oils and fluids we use on a lathe.

If I finish it, I should do all sides to avoid asymmetrical moisture absorption which would lead to warping.

Should I put a sheet of a different material on the top, like a sheet of plywood or aluminum?

When I attach the top to the frame, should I slot the holes in the brackets so that it can expand and contract at a different rate than the base? All of it will be dimensional lumber, so it's not like it's a metal base with a wood top and different expansion rates.

Any other suggestions welcome.

Steve

[NP317]

Lathe size and weight?
RussN

[Wolfgang]

My Emco Maier V 10 P lathe is mounted on a 2" x 8" hollow structural steel (HSS, not to be confused with hss tool bits!) section.
For the 8 mounting holes for the levelling pads I brazed steel bushings into said section, that penetrate from top to bottom and are thus brazed to the top and bottom of the HSS. Although I did not do this, for increased resistance against twisting the HSS should have end plates welded/brazed onto them, also.
For precision work the lathe should not be mounted to wooden benches, especially in regions with great swings in the relative humidity.
If you absolute must do so, be sure to give the wood several coats of sealing varnish in order to reduce the effects of humidity changes.

[tornitore45]

I would glue them but observe the end grain and try to alternate any bias. Kind of trying to imitate the stabilizing effect of plywood. Usually, 4x4 are cut near the tree center.
Seal well with polyurethane varnish and cover with a sheet of aluminum.

[earlgo]

My friend who relocated many plants with machinery for a major US tool manufacturer said never to use wood to support a machine tool. The humidity and coolant spills caused the wood to swell and contract and change the levelness. Of course, he told me this after I had secured my 12" Atlas Lathe to the garage floor. The steel pads are epoxied to the cement.

The wood swelling causes the washers to compress the wood and then drier conditions leave the dent and the fasteners are then loose. (The moving castor is visible in the second pic, but it doesn't touch the floor in use. It is there so the lathe can be rolled out of the garage after I check into the big toolroom.)
We checked this after 5 years or so and I pushed on the lathe headstock, and he could get a DTI reading between the lathe leg and the support. Admittedly not much, but enough to make this very suspect.
Just a FYI
--earlgo

[Steggy]

I would not use wood to support any kind of machine, especially a machine tool.

[SteveM]

Lathe size and weight?
RussN

South Bend 9a with 3-1/2 foot bed (24" between centers).

Shipped weight in the crate is 425lbs. Actual is quite a bit less, or I never would have been able to move it

I would not use wood to support any kind of machine, especially a machine tool.

I don't have welding capabilities at this point and I haven't found a suitable metal bench for sale locally.

I can't let the perfect be the enemy of the good at this point.

Steve

[SteveM]

I would glue them but observe the end grain and try to alternate any bias. Kind of trying to imitate the stabilizing effect of plywood. Usually, 4x4 are cut near the tree center.
Seal well with polyurethane varnish and cover with a sheet of aluminum.

I hadn't thought about alternating, but will do that.

If you absolute must do so, be sure to give the wood several coats of sealing varnish in order to reduce the effects of humidity changes.

This brings up another thought: I should varnish all of it and not just the top.

Steve

[tornitore45]

I can't let the perfect be the enemy of the good at this point.

Love that compact sentence.

It all depends what on what "perfect" and "good" is in relation to what you are doing or plan to achieve

My 9x10 Chinese is mounted on a Craftsman table with a compressed wood dust top covered with aluminum. The lathe is on wood raisers to have more room for clean up into the pan. The tail stock block has provision to forge a twist in the bed, once in a blu moon I check the alignment and the bed level and never found the need to adjust it. My garage is Air Conditioned. Do not use coolant and whatever oil has soaked the wood is not going to change much after years.
I make small model engine and they come out with proper fit and run.
The lathe can fit bearing and piston and can turn with no taper on the length that I care (about 2")

[Bill Shields]

If you use wood...strongly suggest you use something that is as dry as you can get.

A lot of cribbing lumber is green...which in today's market may not be much different than 'kiln dried'.

Gluing green wood is a bit of a lost cause...

If nothing else..maybe bolt the wood top down to a unistrut frame...

I have a SB 9" in my basement set up exactly like that for 60 years.

It is not ideal but gets the job done.

[Rich_Carlstedt]

After gluing and bolting and drying , you may want to find a cabinet shop nearby that will run the top
under a planer or a Sanding belt machine
I took my30 x 60 mapletop bench to one a few years ago and they top sanded it for $50.. very nice. And flat

Rich

[Glenn Brooks]

FWIW, South bend sold wood benches for their lathes for a long while- apparently without complaint.

Last year or so I made up a lathe bench, using 3” heavy wall square tube for the frame and 3”x5”x5’ old growth timbers for the bed. I ran the Timbers through a planner to clean up and square the surfaces, then I used a brisket joiner to align the timbers for gluing. Then marine epoxy to glue up the top. Couple of pipe clamps to hold everything together and control warpage while the glue set up. Can’t see why you would need all-thread to bolt your 4”x4”s together.

You are probably better off to make your frames out of steel tube, or pipe. But the wood top will have the advantage of looking good and damping vibration- which is a plus. Definitely seal and varnish the wood - coat uniformly top, bottom, and end grain with a couple of sealer coats and four or five top coats- uniformly. The wood will absorb some humidity as the season changes. But varnish, or urethane, will moderate your % of moisture intake, and make any humidity induced swelling pretty much uniform throughout the top.

I have more ground water ground induced floor heaving each season around my shop than humidity induced swelling, so never worry about how my machine tools change alignment. I re-level every spring anyway and do not worry at all about any minor change in the wood top.

Glenn