AR400 for welding table?

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I got my hands on a piece of AR400 steel. It is 43.5" wide and 17' long, and 3/4" thick.The plan is to make a welding table from it and I have cut 8' off of the piece. I am building a generous frame but not going too crazy. I have quite a bit of 3" angle that is 3/8" thick that I will use for the majority of the frame. Probably use 4" square for the legs if I can get enough. If not I can use angle but prefer not to.ANYWAY, the plate is flat as it can be. You can put an aluminum level anywhere on it in any direction and not see light under it anywhere. Both sides are perfect and flat and I don't want to damage the backside when mounting this plate to the frame so that I can flip it if the top ever gets messed up.I do not want to weld the top on and wonder if there are suggestions on how to mount this with minimal plate damage. I can't just set the plate on the table as I don't want it to move around. It weighs just shy of 900 lbs so if I manage to move it somehow (someone bump it with a truck is not impossible to imagine) it will take a lot to put it back in place.I don't have room for two tables so will probably sell the rest of the plate.On a side note, the table has a thin even layer of scale on it and my son wants me to remove that and have a nice shiny tabletop. I like the scale as I can write/draw on the table with soapstone and see what I wrote. What do you guys prefer? If I leave it as is it will not be rusting all the time. I never weld to my tables so I won't be grinding on it creating clean spots anywhere.Suggestions?
Reply:Nice piece. You can either weld studs on the bottom and bolt it to a frame, or mag drill two sizes to counter sink bolts, in all four corners. I also like the idea of not making it shiny. Take pics!"Where's Stick man????????" - 7A749"SHHHHHH!! I sent him over to snag that MIC-4 while tbone wasn't looking!" - duaneb55"I have bought a few of Tbone's things unlike Stick-Man who helps himself" - TozziWelding"Stick-man"
Reply:You should have no problem. It will take a lot to damage the flatness of the steel if it is already flat.  The only thing I will say is to spot heat anywhere you want to drill a hole. You can drill it as is but you must use slow rpm and be patient. If you spot heat take it to a medium red and let it cool the drill as if on mild steel. To keep the plate flat when attaching it to the frame shim any voids before welding and do not clamp the table top to the frame.
Reply:Hello Bob, bolting it, for the way that you are describing setting up is probably a very good choice. The only thing about drilling on it is that you will need to pay close attention to not overheating the bit, whether you go with an annular cutter or a twist drill type of bit, that stuff work hardens instantly and then it gets harder than hades. Good luck on your endeavor and best regards, Allanaevald
Reply:There is no problem welding AR400 . It is done every day.
Reply:I agree on welding studs to the top and bolting . Studs would be easier to remove if you want to fill it over.
Reply:Obviously the weight will keep it down ... just weld 4 studs on the underside that will fit inside your base frame won't even need to put the nuts on ... that will keep it from shifting side to side if you ever have to turn it over then just cut them off and grind smooth.Located In SE OklahomaLincoln Mig 135Hobart Ironman 230 Mig5x10 CNC Table with DTHC & FTHypertherm PM65 on the tableMiller Bobcatwww.caneyagequipment.com
Reply:The stud thing sounds pretty good but maybe I will thread the angle and run the bolts UP into holes in the plate. That way I can just fill the holes with welds if I ever flip it. Wouldn't take more than 1/4" bolts or so.Comments/
Reply:Originally Posted by Bob WarnerThe stud thing sounds pretty good but maybe I will thread the angle and run the bolts UP into holes in the plate. That way I can just fill the holes with welds if I ever flip it. Wouldn't take more than 1/4" bolts or so.Comments/
Reply:I would just put a few small tacks here and there around the perimeter. Won't take much to keep it from moving, and grinding a few tacks off is easier than filling holes with weld.
Reply:If you put some angle iron "clips" on the edges the plate will stay just by gravity. Just take a piece of flat stock and attach it to your frame to extend out to the edge of the plate and weld a piece of angle on to it to hold the edge of the plate  sort of like this L______.Only big downside is that you won't be able to use a square against the edge of the table in those points if the angle iron extends to the top of the plate..No government ever voluntarily reduces itself in size. Government programs, once launched, never disappear. Actually, a government bureau is the nearest thing to eternal life we'll ever see on this earth! Ronald Reagan
Reply:A handful of small welds to hold it onto the frame, and leave the scale on it. Shiny tables are silly.
Reply:Here is a photo of the plate sitting on my current welding table. It is upside down so I can build on it.The second photo shows the cut where I cut it from the other 9'.
Reply:Put an inch of weld on the four corners. Shouldn't take a lot to hold it to the frame. It will be tough to drill and tap.
Reply:I have a welding table top that weighs 600 lbs. It overhangs the table frame by 4" all around.I just placed the top on the frame...no connections anywhere. It hasn't budged in over 10 years. How can it?Rich
Reply:I envy you brother. Nothing wrong with a few tacks on a sturdy frame. This plate is not going to move anywhere. Nice score.
Reply:Nice piece of plate for a table top.  I'd build a base that left a 4" over hang all around, set the plate on it, center it up and use 4 (maybe 6)small, 1" long fillet welds to hold it in place.   And I'd be sure to put those welds in places that made them easy to get to with the grinder in case I ever wanted to take it back apart for any reason some where down the line.   I'd want the mill scale left on it.
Reply:Is it magnetic? I made a welding table out of 1 1/4" Hardox 400 that  is so magnetic I have to have a sheet of alum. over the top of it and keep wire feed whips away from it when welding.
Reply:Originally Posted by lars66Is it magnetic? I made a welding table out of 1 1/4" Hardox 400 that  is so magnetic I have to have a sheet of alum. over the top of it and keep wire feed whips away from it when welding.
Reply:Bob,Just in case you're not aware of this thread....http://weldingweb.com/vbb/showthread.php...picture-threadThere's some good ideas to be had in it.
Reply:Lars66, no it is not magnetic.HT2-4956, thanks for that link. I have a lot of plans on the build already but I'm sure I'll get more from that thread.I posted about this on another forum and have been getting a lot of inquiries about the 43.5"X9' leftover piece. This is some serious expensive steel (found a 2'X2'X1/2" on web for $536) and I don't want to get rid of it but I also don't have room for another table and don't know what else I would use it for so I may have to investigate some of the better offers. I really need some tools since I had to sell the majority of mine in the past so maybe I can swing a trade of some kind for it. Maybe I should make a table and sell/trade the table. Opinions?Anyway, can anyone think of a reason to keep it? Not something I come across every day so gotta make a good decision on it.I think on my table that I will just drill a hole in the angle in each of the corners and tap the holes and run a bolt up into a hole in the plate. The plate would just be pinned to prevent movement but not attached at all and just held by gravity. That way I can weld the hole shut if I ever need to flip it. I REALLY doubt I will have to flip it as this stuff is very impact and abrasive resistant. It was a big chore to cut it.Now I gotta go cruise the table thread.
Reply:Bob,On page 14 of that thread there's some of my ideas for table building.And post #13 in this thread has what I consider to be a really nicely done table.http://weldingweb.com/vbb/showthread.php...01#post7143901
Reply:You could have sold that plate to someone to build or repair earthmover buckets out of, took the proceeds and bought a table and put the rest of the money left over in your pocket for your next equipment acquisition or project expense.Will make a nice table anyway.  I would just weld it to the base."The reason we are here is that we are not all there"SA 200Idealarc TM 300 300MM 200MM 25130a SpoolgunPrecision Tig 375Invertec V350 ProSC-32 CS 12 Wire FeederOxweld/Purox O/AArcAirHypertherm Powermax 85LN25
Reply:I wanted it for my table. Even though it is very expensive steel I want the high impact and high abrasion resistance for my table. The leftover piece is  32.625 square feet of 3/4" that is VERY FLAT. I looked online and found a piece of 2'X2' of 1/2" for $536. That is a crazy high (to me) of $134 per square ft for half inch stuff. Mine is 3/4" but if it were half inch 36.625X$134 is over $4000.I am looking to get 1/4th of that for 3/4" and think that is fair given the material. I'm getting some grief for the price but it is easily worth that and is basically new as it has not been used or bent and only has lite surface rust.I made major concessions in cash and trade to get this so please allow me to get my price or just ignore any discussion on the topic. I prefer not to receive negative emails because I won't take a couple hundred bucks for it (and in one case want it delivered about 100 miles away for free with no way to unload it).To those that did make an honest offer, I appreciate you offering what you can and appreciating the value of this plate.
Reply:Bob,Just a thought....you could call some one like Jorgensen Steel and ask them for a quote on an identical size piece of 3/4" AR400.   That would help you get a better feel for what it's local fair market value might be.It is worth no more than. 50 cents a lb today reg plate is. .30 now was down to .25 a month ago.  Steel is a bargan now and offshore is dumped here. Hudson Yard in NY has one building 100000 tons none made in America. Port Authority is letting China bid 9000 tons of bridge at Laguadia Airport.
Reply:damn. Didnt realize that stuff was so expensive.   It is interesting that scrap for steel is so low right now but yet some people on clist and such are trying to sell steel plate for what seems like a ton of money.  What gives?Dynasty 200DX   (2014)Millermatic 211 (2015)Optrel 864   (2014)Smith Medium duty MBA 30510 (Xmas 2014)Tennsmith 16ga 4ft finger brake (2015)Trailblazer 325 EFI and excel Thermal dynamics Cutmaster 82Miller maxtron 450
Reply:On-line metal retailers have huge mark-ups. Buying a full sheet from a proper steel supplier will always be much cheaper per lb. but you need to have a use for that much steel and a way to handle it.A few weldersA lot of hammersA whole lot of C-clamps