Seeing as how the base has to have opening the proper size not only to accomodate the machine, and that part has to be bevelled in, and also another opening for the belt.......you can understand why wood has always been the choice. Now, I just assumed you meant usable in that you want to install a treadle in it. Do you mean usable just as a table or stand?

In that case anything you like. It has casters on it, doesn't it?

If it's like mine, the casters are cast iron and not too floor friendly. I had one I wanted to use the same way I think you want -- as a table. Mine is all rusted which I like a lot and I wanted it for my porch outside. DH made it a table by using the part cut out of a counter top where the sink goes. It's about the right size, but not nice enough looking for anything but porch use.

I wanted marble until I found how much it would cost! Maybe someday. . .

I had one that I used a piece of butcher block on it. I used for an island in my kitchen (one kitchen had 12" of countertop space; another had absolutely none!) The piece was 24 deep and 36" wide.

After 30 years of hard use, the butcher block cracked (yea, I know .. I should have taken better care of it but by that time, it was plant stand!) So now ... I use it as a small dining table (for 2) in a small gazebo. We found an enameled top from an old kitchen table and put it on it.

And when you look for stone .... go directly to the fabricator and ask to see their mis-cuts and mis-ordered pieces. If you are flexible, you can get pieces extremely cheap. I covered a 36"x48" island in solid surface for $25/ 9' laundry folding area in solid surface for $125 and a 36" vanity in quartz for $100.

I have 2 that I plan to make into end tables. I'm thinking a nice piece of stained oak on each.

My Mom's treadle Singer machine did not need any modification to become a table. One merely lowered the machine below the work surface (to stow it) and the hinged top with flush hinges folded over the top providing a flat, nicely finshed wood top. The top was solid walnut and finished on all sides. It was a piece of furniture when the machine was stowed.

Right, so do my treadles, but mileaday said her top was missing. (er, I mean the cabinet's top) LOL.

Opps! I said my mother Singer machine had a walnut to top. That's wrong. The cabinetry is oak.

I too have a treadle machine base. I turned it into a sofa table using quarter inch glass. I had a piece cut to the size I wanted and had them polish the edges. I used small rubber adhesive pads under the glass to prevent it from sliding. Worked great.

My mother had a tredle Singer sewing machine. (The machine is still in the family.) The cabinetry is oak.

The small iron wheels do not roll very well and squeek if those have not been lubed. The wheels do not swivel and the small diameter is rough on finished floors. The usual way of moving the machine while turning was to lift one end and move as a wheel barrow. It may rest on all 4 wheels for straight line movement.

You may wish to attach modern, non-marking casters to ease moving it about. Consider locking casters for two of the wheels to keep the table in place.