Lathe Stand Advice Needed

[Nesse1]

Getting close to finishing this stand. The top plates as shown below arrived today and are just sitting on the unit (not welded yet.) I'm second guessing using 1/4' steel for the plates. Will this be reasonably rigid for a 12x36 900lb machine? Or, buy some thicker plates? 3/8"? Another thing, I'm thinking about cutting off a strip of the plate from the tailstock side plate, and moving it to the headstock side, to cover up the middle leg, for additional support. It this just silliness?

Open to suggestions...

 

[great white]

I’d probably back it up with a piece of I beam underneath that the mounting bolts go through.

doesn’t get much more “rigid“ than that.

It’s what I did under the steel table for my Atlas….

 

[Nesse1]

Oh, another thing, I want to buy a tool box and slide it into the large opening space. Harbor Freight has a nice one, but it's really deep (21" where the stand is 17.5" across.) I've seen photos/threads here where guys used a similar HF box with an even narrower stand, but I'm concerned about the stability of the box. Suggestions on that welcome too...

 

[Nesse1]

I’d probably back it up with a piece of I beam underneath that the mounting bolts go through.

doesn’t get much more “rigid“ than that.

It’s what I did under the steel table for my Atlas….

Got a photo by chance? I'm not envisioning an I beam...

 

[verbotenwhisky]

Oh, another thing, I want to buy a tool box and slide it into the large opening space. Harbor Freight has a nice one, but it's really deep (21" where the stand is 17.5" across.) I've seen photos/threads here where guys used a similar HF box with an even narrower stand, but I'm concerned about the stability of the box. Suggestions on that welcome too...

That looks stouter than the stand that came with My PM1236...

 

[great white]

Got a photo by chance? I'm not envisioning an I beam...

Nope.
the ibeam is under the table top and the four mounting bolts for the lathe go through the top and through the I beam on one of its sides.

adds rigidity to the lathe and makes it nearly impossible for it to come out of “true”.

essentially, the lathe bolts to the i beam and the table “more or less” just holds the ibeam off the floor.

Think of the i beam as a “torque tube”….

 

[Nesse1]

Hum. I don't have any I beam sections, but I can get some C channel sections. Those can be welded into the stand for top plate support.

BTW, these are the best part of the stand! Found them on eBay for dirt cheap. I chuckle every time I see them.

 

[Ultradog MN]

The more mass you give your platform the more stable it will be.
If I were to build a platform for a bench top lathe I would pour it out of concrete.
Not one big, square block.
Build a form. You can sculpt/pour concrete into infinite shapes.
Incorporate hold down points in the pour.
Looking at the size and weight of your machine I would pour about a ton.
My lathe is 14.5 X 30 and weighs 4000+.
Mass is your friend.
I enjoy seeing other's projects.
Thanks.

 

[G-ManBart]

I'm a bit confused by the design. Why have one middle leg inside the long top tube, and not both?

Going from 1/4 to 3/8" flat plate isn't going to add much rigidity, and adding a strip over the middle leg won't do much either. Until you get up to something like 3/4" thick plate it bends, flexes and vibrates pretty easily.

Cross bracing under the flat plate will make a much bigger difference. Even 1" square tube spanning the long top tubes would make a world of difference. The challenge is getting them in place perfectly flush with the top of the long top tubes so the top plate is evenly supported and not pulled out of position when welded. Along those lines you would have to limit how much you weld the top plate to anything...1/4" will warp very, very easily so you'll be limited to big tack welds.

 

[GL]

To eliminate/greatly reduce the harmonic from my 1340GT using the PM stand, I added a 3/8 plate to stiffen the top plate. Then added several 3/8x3 vertical stiffeners to tie everything together. The top of the original stand is maybe 12ga and bowed from weld draw. Tying things together flattened the top also. Adding the toolbox in adds a bunch of mass to the system. As others have mentioned, there are several designs others have built to provide ideas but you are pretty far along so adding in stiffeners is your best bet. Headstock end is more important than the tailstock end - but what you are really trying to do is use the stand to stiffen the bed as well as damp vibration. Closed section are better in torsion - welding in a channel legs up makes it a tube. Looking good though. I wish I had waited and built my own stand.