How would you fix this?

[Rickenbackerman]

This heavy steel cabinet/cart thing was in my shop when we moved into the house:

The top is about 3' by 3', I currently use it to store all my electric power tools, and my drill press is bolted to the top. I want to use it as a welding table - problem is the top has about 1/2" of upward bow in it, presumably from warpage when it was welded on. Any ideas how to get a flat surface on this thing? I'm not sure I can remove the top that's on it now, it's either 3/16" or 1/4" plate and is welded all around the perimeter. I think it'd take me forever to cut the welds with my trusty angle grinder. FYI there is no framework underneath, only angle around the outside.

I was thinking of welding up a "new" perimeter frame of square tubing and finding another piece of steel to bolt to that, but was wondering if anybody had any better ideas.

 

[z28snksknr]

you could try heating it with a oxy/acet torch and quench it with cold water to try to shrink it down a bit, but it will never be truly flat again

 

[D KRAGER]

Yea I'd just add to the top. Make it level and go from there.

 

[NASTYZEN]

I would go the new top idea.Get a 1/2 plate. Make threaded holes every 6 in.in it and you could dog clamp your work to the table.
Just me 2 cents worth.

 

[TheGrooveking]

Take the top plate off and put it into a large hydraulic press.

TheGrooveking

 

[toolsd]

Heat the middle to cherry red, the area about the size of a quarter, and quench it. Work in an expanding circle, until it's flat enough. Slow and tedious, but it should work. You are correct about the welding having caused the bow to begin with, most likely.

Tools

 

[gorilla]

You need to shrink the table top to remove the bow, try welding a heavy bead about 3" in diameter around the center of the high spot on the high side when the weld cools it should shrink some of the bulge out repeat until your happy with the flatness. Grind the weld beads off when your done.

 

[Spareparts]

If you have the room underneath put a thick piece of angle iron underneath the top from one side to the other and drill a 3/8" hole in the center of the top and the angle, put a 3/8" bolt thru them and tightem it down. If it pulls the top down to your satifaction pull the bolt out chamfer the hole and put a flat head allen bolt in to make it flush, might need a couple of them.

 

[Jzytaruk]

put a new top on it.. anything less than 1/2" will warp.. 3/4 would be great because it'd give ya enough "heft" to bash on it with a hammer and not get dinged up.

1/4 or 3/16" pl is way too thin for any welding table, it would warp first sign of any heat. You could use a strongback, but it wont prevent warpage on the non-reinforced areas.

Using a press is tricky. You'd probly just stretch it all out.. Heat would work but it would never be flat... and it'd still be flimsy.

edit: speling

 

[Rickenbackerman]

So where would I source a 3' by 3' piece of 1/2" or 3/4" steel?

 

[Jzytaruk]

local fabshop, or metal supplier. I know around here I'd have to check out Russel Steel, CW Carry or Price Steel. Not sure where to look outside of Edmonton, AB.

 

[cal67ss396]

You could try pushing it backdown with a deadman!!!!!

 

[rasit]

You could try pushing it backdown with a deadman!!!!!

Dead men don't push back.

 

[CKC]

Weld down 1" X 1" Square tube or whatever size is available around the perimeter and install a new 3/4" plate on top of the tube

 

[Rickenbackerman]

Well, I scored a really nice piece of 3'x3' 3/4" thick plate off of craigslist for pretty cheap. Blanchard ground (even the edges) and looks to be pretty flat. Might be out by 40-50 thousands along one axis, but I can live with that.

I decided to cut the old top off. I want the underneath to be as flat as possible hoping it might flatten the plate out. Started cutting ~12 feet of weld.

A couple hours later... the little plate on top is a shelf I'm going to weld in the cabinet before I put the top on.

How I unloaded a 275lb plate by myself...

Oh, and here's a cool clock I got from the same guy. I got the plate (with heavy duty legs - in storage now), the clock, a nice set of casters, and an old Vaughn ball pein hammer all for $180. I think I did good. The clock lights up plus the silkscreened part and the front are both glass.

 

[Brad54]

Now, do NOT fully weld that top to the cart like the other guy did!
I know it's a lot thicker, but you have no reason to do a full perimeter weld and build up heat.
If it were mine, I'd tack all the corners, and then start at one edge and weld a two-inch bead, skip two inches, weld two, skip two, and then go to the opposite corner and repeat going the opposite direction. Repeat on the remaining two corners.

If a weld ever does crack, it will stop at the edge of the bead, rather than continue on along the entire length of the bead.

-Brad

 

[gorilla]

You may want to consider bolting that top plate on with some flat head screws. You won't warp anything that way.

 

[Rickenbackerman]

Yup, it's done - bolted on with four 3/8 countersunk stove bolts. I'll snap some pics when I get a chance.

 

[Jack Burton]

You may want to consider bolting that top plate on with some flat head screws. You won't warp anything that way.

Good advice.

Yup, it's done - bolted on with four 3/8 countersunk stove bolts. I'll snap some pics when I get a chance.

If you want to get that top as flat as possible, maybe you could make a 5' sanding block out of extruded channel and emory cloth and mark up the plate with a sharpie to see the high spots. While this method will not guarantee levelness, it will make it pretty damn flat.

 

[Rickenbackerman]

Jack, unfortunately the plate had a bow along one axis of it - when I bolted it down, the whole thing kind of potato-chipped, if you know what I mean. It's probably only out about 40 or 50 thousands but I can live with that. It's 1000x better than it was before, now I can at least USE the fool thing.

Oh, I also welded in a shelf when I had the top off for more power tool storage.

 

[mdbeck1]

...

Oh, I also welded in a shelf when I had the top off for more power tool storage.

It also looks like you added a Jack Olsen receiver hitch vice mount...

You had better watch out or you'll start mounting other things that way...
- The bench grinder
- The anvil
- ...????

 

[gorilla]

I've found that if you work from the center out to the edges you can often "pull" a bow out of a plate. Works the same if you're welding or bolting. That table looks nice!

 

[NASTYZEN]

Turned out nice!
Look out for that trash can when you weld on that new work bench.
If there's one thing I've lit on fire more often than others ,it's the trash can.