Help with welding table build and design

Scored a 5x8x1"thick plate for dirt cheap. 1632lbs total according to the charts.
Now I'd love to find a cheap way to have the edges of this plate cut/milled/lasered perfectly, but I dont know if thats even possible to do affordably, so the factory edges will have to suffice for now. They're not too bad really.
I'm really just looking to drill some holes in a 90 degree pattern (a big L shape at each corner) to drop locating pins down into so that its very easy to quickly weld two pieces together at 90 degrees. Since I've no cnc laser etc, I just plan on laying it out the old fashioned way with a machinists square, a center punch and possibly a mag drill for the holes. Holes will also be drilled for hold down clamps to drop into. Is this an acceptable of doing all this?
Any recommendations on which specific clamps to use in the middle of the table? Bessey? Or??
Finally, I would appreciate a simple recommendation on how to frame a table to support this top? I was planning on either using rectangular tubing approx 5"x2"x 1/4"wall OR maybe some 5"x2" x 1/4"wall channel? I'd come in about 6-12" from perimeter and use crossmembers on 3' centers maybe? Maybe 4" square tubing for legs and a total of 6 legs.
Anyones help/opinions on this would be appreciated.
My last dilemma is how to weld this frame up SQUARE/PLANULAR without another welding table to work off of. Considering just framing it off the plate itself that currently resides on my driveway atop 6x6 wood blocks. Its pretty straight, but you can see a VERY SLIGHT curvature/bow when you look down its length. Thanks for your thoughts guys.

The time and money you spend on this would be better spent looking for a 5x5 or 5x8 platten table, acorn or weldsale are the big names. It will be flat. The plate you have could be sold for more than you paid to fund such a purchase. If it is more than sagging under its own weight you will not get that bow out of the plate.
It took a couple years of off/on looking but I have 8 5x5 plattens, and have not been buying them as they come up now.

Rob F. said:

The time and money you spend on this would be better spent looking for a 5x5 or 5x8 platten table, acorn or weldsale are the big names. It will be flat. The plate you have could be sold for more than you paid to fund such a purchase. You will not get that bow out of the plate.

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I agree with this comment and would add that I purchased and assembled a table from weldtables.com I selected 1/2" thick with pre-drilled holes and tapped holes which is really more than is needed due to the 6" tall interlocking ribs with a tab and slot design.

If you really need a table that size, you may be best off staying with what you have, bat as stated, you will not get the slight bow out and this will rear its ugly head with every project.. Good luck..

I made my own table, similar to the other fixture style tables, by just designing a pattern and having it cut from 5/8" plate at my laser shop. I think I'm under $800 into the table that's 84"x30". Three big plates that I can just barely move myself. No friggin way I would want a table THAT heavy. The big key to success on my table is that the three plates bolt to the top of the frame and I use shim stock between frame and plate to get everything level. I've got the whole table between 1/64-1/32" flatness in any direction. I don't think you'll get that with your big plate.

I had the hole pattern laser cut, 5/8" hole every 2", and I use the standard Stronghand clamps. Works great. I oversized the holes a bit. Plenty beefy to bang on.

You'll be all right with what you have. Build a frame and get the plate on it, convex side down. The plate can pulled straight with a "mast" and a couple turnbuckles, threaded rods, chain binders, whatever, if necessary. The straightening device can be incorporated into the frame, too. And if that doesn't work, cut it into sections that are flat enough for what you need. That's what torches are for....

Good idea to tuck the frame well under the edge. I do think that your frame components are heavier than necessary. Six posts of 2x2x1/4" angle iron would hold it up. Any additional shelving components welded in will stiffen everything up.

And, just my personal preference, add drawers for tools like strikers, soapstones, small right angle plates, tip cleaners and the like. All the things you need handy. A shelf for grinders, a bar to hang welding visegrips on, storage space for whatever fixturing system you settle on, shelves for stock. You'll be accumulating a lot of it, hopefully. And don't worry about the edges too much. That's what grinders are for. I do a bit of sheetmetal work, and frequently grind a section of table edge to a shape handy for the job I'm doing. Welding tables like yours can be fluid - adapted for the job at hand and changed according to your whims of the moment. Cast iron tables, less so.

My $.02....

Good luck, post pix!

increase leg sizing, 4x4 3/8 or 5x5 at least. 8 feet will need an apron, we use 8 x angle drop at work, but our tables are all 20 ft. A steel service center can plasma your table, dimension it about 3/4 shy of existing dimensions, and have a dwg file in hand for dog holes. My personal table I have switch to square holes like a wood bench and am making a wood style vice flush mount. The cabinet maker design is just better than any weld table I have seen. for fabricating, level table on donage, blocks, shoes, tire rims whatever, with camber down. weld legs and stich bracing on. when you flip table over the camber will drop to a more flat. You can avoid holes too, the mig is the easiest bench dog, universal fit too!

I have 2 4x8x1" tables myself i bought used and cheap. The tables over time have started to bow down. It's been about 6 years on 1 and 8 years on the other. They were made from 3" sq tube frame.

I suggest you use all I beam since you buy odd and small sized beams for very cheap and build a very heavy duty frame to keep it from bending over time.

1 day I can be doing the smallest tig welds on small stainless parts, next day rebuild an excavator attachment, the next day build a conveyor, next day a hand rail. So I'm very different then most people.

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Thanks so much for the replies. I appreciate them all. I previously stated this plate currently resides on 6x6 blocks on my driveway. I thought it had a slight bow but it was just the uneven driveway and the 6x6 blocks creating this slight bow. It is easily manipulated via shims to get it perfectly straight.
As much as I'd like to outright buy a welding table, I just see this plate sitting in my driveway and I have to think that just $400-$500 in steel would frame it up nicely and be done with it.
This all, as opposed to searching forever for a prebuilt table, having to pay for it, and then having to deal with shipping it.
I know this 1" plate will make a great table with a little time and effort.
I've just been contemplating the best way to build the frame to get it square. Since I dont have anything else to build on, I'm considering just shimming the plate as straight and flat as possible, and then building the frame right on top of the plate itself.
I don't have expensive straight edges etc though. Would it be foolish to just use very fine string lines (kevlar braid type material?) to check that I've shimmed it flat before I start welding/fabbing the frame off of it?

a torpedo level and squarish is fine. you level with leveling screws once it is in home. floors are not level. A good beating on table is the most used tool in a shop.

If you are going to make the frame to support the table I would use 3or 4" tubing or some small 4 or 5" wide flange beam to support the top. Legs tube for sure, Use stainless gussets so always have a clean rust free spot for the ground clamp.
Lay the two long pieces on top of the plate where they would go (but on top) and sight across them side to side. Get back 10-20 feet so you see it all at one time. If they do not eyeball perfectly straight with each other shim accordingly until they do. Then you have the plane of the frame so just add cross bars flush with the two long ones. Add legs and gussets, set top on table frame and bolt it on. DO NOT tack it or weld it in any way or any place. It will warp. Bolt it.

Build the frame first where it's gonna live then set the top on it. Saves flipping and more handling of the top.

memphisjed said:

increase leg sizing, 4x4 3/8 or 5x5 at least. .... You can avoid holes too, the mig is the easiest bench dog, universal fit too!

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Totally agree on tacking fixtures down. I am puzzled though, as to your recommendation for leg sizing. The top only weighs 1600lbs. If he adds another 1600 lbs of stuff and/or work on the top, 3200lbs. 6 legs, approx 550lbs each. A 3/4" round would hold that up, with plenty to spare. I may be missing something.

My table is smaller at 3x5 but is 1.25 thick. I did not drill holes but did go with 4 square legs and 3x4 perimeter frame.
That build was many years ago, I thought I was going to fab 5 new tables last spring and did quite a bit of looking at that time.
These folks seem to have a good system the project fell though so I did not end up buying them. But the video is a good tutorial on building a table when you don't have a table to build on.
2'X3' Welding Table Top Kit-Most Popular PRO TOP KIT - WT2436-PRO-U – WeldTables.com
You will need a good straight edge for this and most other projects and a decent 4-6 foot level is a good start. Holes, I would call around and find out what it would cost to have a pattern of holes done for you. It might not be bad as you think..its a lot of holes to do with a mag drill
Gary

Don't use anything besides tube for the legs. Open sections (angle, channel)are weak in torsion, and even though they will keep the table top from collapsing to the floor, they will make the table wiggle every time you bump it with your hip or drop a piece of steel on it. Tubes are ideal for a table base.

This may sound sacrilegious but cut either a 2ftx3ft corner off of it or a grid of 1ft squares out(or something similar) of half of the plate. Make a smaller lighter "satellite" table that can be moved around where ever and still be at the same level as the main table if you go for a larger chunk or make frames that set the 1ft squares back in like plugs with a cut width gap. Maybe casters but absolutely use leveling screws/pads for the satellite. The cut out sections can be used for awkward things that don't want to play nice on a flat table due to existing features, like a tube/pipe with a disk somewhere in the middle of it or something with odd curves and features but "flat" ends or whatever.
I have a nice big acorn table at work and those are all features I wish I could have on it. I also have a 2x2ft 1"thk square that was used as a test after our Blanchard grinder was repaired. I used 4 drops of 1/4" wall 3"OD pipe for legs and then ended up welding it to an old cart from a dead syncrowave. I ended up putting a thermal arc 185 on top of the water cooler and I had a mobile welding table that was more flat than necessary. It worked awesome for small parts that fall through the acorn table holes...

adding in some lower mass and removing flex for beating on and encouraging fit of steel parts that need some direction. mostly flex, the weight is just a byproduct of cross sections. I am a believer in reducing weight on most things except tools used as anvils. I prefer pipe for legs, it doesn't bend with twist; alas most people don't have easy access to 3 1/2 std or better pipe.

I bought 7'6" x 12' table at an auction that has tons of ribbing underneath, they had it milled flat before they went out of business, I then spent about $ 1200.00 to have approximately 70 in it, I then bought 20" strong hand clamps, cut the end off, welded a 1" pin to all 8 clamps..., its the best table I own, I'm going to do my other tables the same way.
So I have less than $ 2500.00 into this table and I wouldn't sell it for $ 10,000.00