5mm for the top and you will need little for reinforcing, 100 x 100 legs will be fine. Seems agood plan to me . Noel

Hi, I know this is not steel but I thought it would give you an idea of bracing needed to give it strength.This has had various heavy car parts on it including engines and gearboxes. It’s been outside for 5 years

Maurice

As others have said above, welding directly to the 5mm sheet will likely pull it out of flat, but the 4x50mm bar should act as reasonable bracing for the legs; In my case I used 40mm square box section.

For the top, I have used 43mm thick high density chipboard, recovered from a factory mezzanine floor, The whole setup is plenty rigid, but obviously the top surface would be susceptible to damage; second hand thick kitchen worktop would do just as well.
I my case I've covered the chipboard with some laminated flooring, but adding the 5mm steel sheet would seem ideal.
It will be hard wearing, and suitable as a welding surface, but with the thick chipboard backing, also be well supported and quieter than if the steel was used on its own.

p.s. when coming up with your measurements, don't forget to allow for the height and fixings for a decent bench vice if you intend to fit one.
When I set up mine, I had a smaller vice than the one I now use; the replacement is taller, and so raised the height just too much for comfortable hacksawing.

Bill

Edited By peak4 on 12/03/2023 19:59:23

Shown below is how Mac Industries [I have no connection with them] create a welding table surface that is likely to stay flat:

I would suggest:

• Welding on 50×50 tabs to your 4×50 bar, ideally so once assembled into a frame there's one in each corner, with one in the middle of each short side and two at ⅓ and ⅔ along the long side.
• Weld up the frame with the 4×50 bar and 100mm tube on as flat a reference surface as you can (your workshop floor looks quite flat in photo's you have shared.
• Flip the frame over and place both pieces of steel plate on the frame, line up and clamp in place.
• Using a hand drill, drill 7mm holes through the plates and the tabs.
• Take the plates off and tap the hole in each tab with an M8 thread.
• Drill out the holes in both plates to 8mm, and countersink.
• Bolt the plates down with M8 countersunk machine screws.

Et Voila, you have a flat sturdy workbench with a 5mm thick steel top.

If you want to improve rigidity, there are two upgrades or one change you could make to your existing design:

1. Add further braces in the middle going the other way to your existing ones when welding up the frame and put some extra tabs (& bolts) in the middle where the braces meet. If you do this: drill, tap and bolt those holes in the middle first, then drill the outside ones, take the top back off and tap the outside tabs, and re-assemble, to reduce the risk of a misaligned hole causing the plates to warp.
2. When you weld the frame up, add additional braces to the legs about 100mm up from the floor to stop them splaying outward, they can be between the legs at say 100mm off the floor (which would allow you to put a plywood shelf on it) or at a 45° (which is better if you want to put boxes of stuff or a small welder/compressor under it.
3. Make it 1m×1m instead and use both plates bolted down together to make a 10mm top.

Edited By Jelly on 13/03/2023 01:07:38

Sturdy old wooden workbence/table with sheet steel on top. Extra support as necessary from vertical tube?

OR

this baby with added tubular vertical support as required

Edited By Clive India on 13/03/2023 10:21:02

This would be my preferred option normally, but I get the impression Sonic would want to use it as a welding table.

An application where I have learned from experience that you can get wood smoldering hot underneath a large metal plate intended to protect it if you're doing a lot of bigger welds in PA/PB (flat) position with the back of the workpiece in direct contact with the table.

Edited By Jelly on 13/03/2023 12:37:51

That's looking like a very beefy workbench right there, definitely puts my welding table to shame.

The braces on each leg are a particularly good move.

Regards gluing the top in place, it's actually quite a good idea for flatness and rigidity… But just be aware of how your adhesive reacts to heat if you're planning to use it as a surface for welding on, or it may suddenly come loose.

I would be inclined to use phosphoric acid (or a suitable phosphoric acid based rust treatment*) on the top of your table, wipe it down thoroughly and then apply a light machine oil or as you suggest a wax.

The Iron Phosphate produced by the rust treatment will result in a dull black finish which is reasonably hard wearing and will retain a protective layer of oil or wax on the surface without being greasy to the touch.

Painting the surface will not wear well, and most likely result in localised rusting wherever it gets scratched, giving you a worse long term outcome.

* Quite a few rust convertor products have a mix of weak phosphoric acid with a varnish or sealant, which is good for metal that will be painted, but would actually work against you when trying to prepare a surface of exposed "black phosphate" to be oiled/waxed for long term protection.

Edited By Jelly on 01/04/2023 22:16:21

How would you suggest attaching that to the surface of the bench, David?