What thickness for fab table top?

[thebobcatkid86]

A couple years ago I bought a very heavy duty table to use a as my primary fab table. the top is 36" by 64". Its made entirely out of 3" channel and is mounted on 10" industrial steel casters. I scored it for about what one caster costs new. It is however in need of a new top. The current top is something around 3/32" or 1/8" and it is severely washboarded to the point where it cant really be used for layout. Luckily its only tack welded from the underside so removal shouldn't be too terribly difficult (angle grinder). I'm wondering how heavy a piece of plate I should buy for my new top. I'm thinking somewhere between 1/4" and 1/2" but specifically what that I'm not sure. My one other thought is that I'm thinking of getting something heavy enough that I could get a piece 36" x 72" and let the excess hang over one side. This would be so I could cut a sizeable rectangular hole out of the overhang for doing fully supported cutting like my dads uncle has in his shop. But his table top is something like 1" or 1-1/4" (hes a professional fabricator). Id like to hear your guys opinions, as well as any other ideas like my cutting hole that I could do to make this thing as functional as possible.

[denrep]

Originally Posted by thebobcatkid86

. . .My one other thought is that I'm thinking of getting something heavy enough that I could get a piece 36" x 72" and let the excess hang over one side. This would be so I could cut a sizeable rectangular hole out of the overhang for doing fully supported cutting. . .

Sounds like 3/4" minimum, to me.

[Jim Stabe]

I agree, 3/4" at least. Thats what I have on my 4' square table (6" overhang all around) and I wouldn't want any less.

[thebobcatkid86]

Wow, 3/4... that's pretty heavy, and you say at least, so would a full 1" be better? I guess in this business its hard to have too heavy. If I were to scrap the overhang idea, could I go for something lighter, like 3/8 or 1/2? Conversely, is an overhang something I'm going to wish I had if I don't? And if I do have overhang would it be good to have it on more than one side? Say on one long and one short side? or all the way around? and how much?
I don't weld/fab professionally, at least not yet, but I do enjoy the stuff that Ive done. Even though its really just a hobby for now I want to make sure that every piece of equipment that I own is as useful, versatile, and durable as it can be.
I have access to a plasma cutter from a friend of mine, which is what I was planning on using to modify the overhang portion however its maximum severance capacity is 1/2". Though too, my steel supply is also a job shop so I suppose I can have them modify it for me, as Im not very proficient with my cutting torch and I want it to look fairly professional. I don't know if there's a name for the hole near the end of the table but you guys know what I'm referring to right? Is it a good thing to have?
My one other issue may be actually getting this piece out of my truck and onto the table frame. My "crane" as it were, is a very small skidsteer which has a book lifting cap. of 750 lbs. Short distance, on flat concrete, I can probably lift a little more than that but even so, whatever I buy especially if I go a full 1", its probably gonna be close.
Any particular alloy to ask about? or is normal A36 sturdy enough?

[DSW]

I agree thicker is better. My 2'x4' top is 3/4" and I can move/ load it in the truck by myself with a bit of work.

As far as the overhang, I'd go as deep as the clamps you have will go. That lets you clamp to any egde you want as far in as the clamp will reach. My buddies bench someone in the past chopped the top so it would fit tight to a wall. Now in the middle of the room, there's no overhang on one long side, so you can not clamp to that edge.

[mla2ofus]

Ihave a piece of catwalk grating, the kind made of flatbar on edge, mounted flush w/ table top to use for a cutting surface.
Mike

[Burnit]

One more vote for "thicker is better"

I would get the thickest plate you can safely handle, if you go too thin, you have to put something under it to keep it flat, especially with the overhang you are considering.

[oxy moron]

i have 48x48" 1/2" thick...but i only weld paper clips, thumb tacks, razor blades, coke cans and aluminum foil. yes, i'm being sarcastic

what are you guys welding that you need tops so thick?
is the extra thickness for heat dissipation?
extra thickness keeps the top flat? to what point is there a point of less return? sure, a 3 inch thick top dissipate heat real nice and keeps itself flat, im sure much nicer then 1/2 inch top, but if you're going 3 inch thick already, why not get 3 3/4?

I've seen some amazing (pro) fab work done (not by me) on a half inch thick top. but that's just me though.

[weldbead]

Originally Posted by mla2ofus

Ihave a piece of catwalk grating, the kind made of flatbar on edge, mounted flush w/ table top to use for a cutting surface.
Mike

me too! i keep it outside on a pair of metal sawhorses.. i is an excellent table..weld on it, cut on it, it stays flat because its mostly a void...

[Burnit]

Originally Posted by oxy moron

i have 48x48" 1/2" thick...but i only weld paper clips, thumb tacks, razor blades, coke cans and aluminum foil. yes, i'm being sarcastic

what are you guys welding that you need tops so thick?
is the extra thickness for heat dissipation?
extra thickness keeps the top flat? to what point is there a point of less return? sure, a 3 inch thick top dissipate heat real nice and keeps itself flat, im sure much nicer then 1/2 inch top, but if you're going 3 inch thick already, why not get 3 3/4?

I've seen some amazing (pro) fab work done (not by me) on a half inch thick top. but that's just me though.

Its more about making sure it stays flat.



A friend and I built four tables Identical to this one for his fabrication business. He specializes in Stainless, mostly for the food service industry. Almost everything he makes can be lifted by one person onto a pallet.

The top on that table is 1" thick. It was heat treated, stress relieved and then blanchard ground to make it as flat as possible.

The tables we have where I work range from ten to fourteen inches thick, they are actually old Cast Iron tables from machine tools, they are the size of a driveway and weigh tens of thousands of pounds.

You're right, plenty of great fab work has been done on thin tables, the stainless tops of Snap-On boxes, the floor in your garage etc....

We say thicker is better because it usually is. This guy has already mentioned he owns a Skid-steer, what if he needs to repair something heavy on it? Something he bent?

A 1/2" thick top probably won't stand up to having a Skid-steer bucket chained to it and then heated/beat on and bent with porta-powers.

To answer your first question about what we are welding that we need thick tables?
All types of stuff!

[thebobcatkid86]

Well I went out the garage this afternoon and after remeasuring the frame of the table I find it is in actuality 36" x 55". Memory got the best of me... and Im only 22 haha. Anyway, most of my clamps that I own are 6" or less throat but I do have a few 8 inchers. After listening carefully I have decided that a 48" x 72" top, 1" thick is what I would ultimately like to have. Centered, this allows for 6" overhang on the long sides and about 8" on the short sides. And besides being heavy enough to do anything I could ever imagine, that also gives me enough mass to drill and tap bolts on the edge to mount a piece of catwalk for a cutting surface... just a thought.

Burnit - you mentioned yours was heat treated, stress relieved and blanchard ground. My steel supplier that I was planning on buying from, they are a job shop but their website doesnt mention anything about those processes. Would it be in my best interest to find a supplier, or possibly another facility with those capabilities? and how much would those cost for a piece of steel that size? Also is A36 mild steel adequate, or is there possibly some other alloy that I might look into?

I read another thread on here about table tops, and one reply was saying dont not under any circumstances, weld it to the frame. He was sayin even 1" will distort, the suggestion being to drill and tap the underside to bolt to the frame. I was planning on using a few 2" long fillets, probably with 1/8 6011, from the frame to the top, which is what is on there now. Should I be worried? Would a different rod be less likely to cause problems? or should I drill and tap? Id hate to spend all that money and time and effort just end up with a not flat table.

According to a steel supply calculator that I found, its around 980 lbs. Now I just have to call the steel yard around the corner and get a quote.

[DSW]

Check the price on a full 4' x8' sheet while you are at it. Often the price can go up if you don't get a full sheet. I'm frequently amazed that I can get the full sheet at almost and in one or two case less than a short sheet. The weight on 1" will probably still make it pricey, but if it's not too bad you can have a small table also, just for beating and so on if you want.

[thebobcatkid86]

So, dredging up an old thread here, had put this project on the back burner for awhile. Finally called the fabricator/supplier around the corner from me, and quoted me $550 for 3/4" and $680 for 1", 4'x6'. You guys have said time and time again that heavier is better.

Currently, Im debating whether my Bobcat 453 is enough to lift this piece into place or if I should spend a little more and take the table to them have them set the plate with their crane and tack it on. Book lifting spec on the loader is 700lbs.

[Jim Stabe]

a 4' x 6' piece of 1" plate weighs 816 lbs, 3/4" is 612 lbs. I have a 4' x 4' table with a 3/4" top and the top alone weighs just over 400 lbs. One thing I did was to bolt the top to the table frame from below. I drilled and tapped holes in the plate and set it on 1/4" thick rubber pads then bolted from underneath. This did 2 things: one it didn't warp the top by welding and two, it took a lot of the ringing out of the steel of you are pounding on it.

[thebobcatkid86]

I just talked to the shop around the corner, the guy said hed sell me 4' x 6' 1/2" for $250. My main concern is the rigidity when clamping to what will be overhangs of 6" on the long sides and 8" on the short sides. How much more of a potential for bending is there over 3/4"? When Id called this same place 3 or so months ago I got a phone quote of $550 for the same in 3/4" What do you guys think? Am I being too picky?

[mot krig]

Personally, I think you're way over thinking this whole thing. I used to work at a decent sized, very successful welding shop and all their tables were 1/4" except 1 that we had for HUGE excavator buckets and forks and stuff. it was 4 or 6" thick and flat and all that crap, but it wasn't Blanchard ground. that's just overkill. Anyway - 99.9% of everything we did was on the thinner tables, and they worked JUST FINE.

Look at it this way - if you're welding on your garage floor, ANYTHING will be better. a little planning goes a long ways - but the diff between 1/2 and 3/4 is quite minimal. If it were me - I'd just go with what was the most readily available. if you bend an edge - you're a metal fabricator, heat it up, bend it back, and add some gussets so it don't happen again.

time is money - if you're spending extra time on jobs welding them on the floor while you plan the perfect table that will never break or need modification, you're wasting money.

if all else fails, you can always sell the table you build on CL and build a new one - cuz it probably ain't going to be perfect on the 1st try.

[1-800miner]

If you are going to weld and cut on it ,dont even consider blanchard grinding the thing.First time you stick some slag to the table,all that accuracy is gone.
If you want a one inch top but can only come up with half inch plate? Double up! Weld a half inch plate to the legs then bolt the second plate to the first.When the top plate is fubar,you still have a good foundation and less cost to replace the thinner top plate.

[Eric C]

i have tables built from 3/8, 1/2 ,5/8 and 1". Thicker is always better. I just got a quote from a grinding shop in Alabama- 4'X8'x 1" ground flat on one side and milled square on all four edges- just a hair under $1500.00. Thats delivered to Nashville too. This table will be for tig work and furniture building. I like the top to be heavy enough you dont have to weld it down. If you mount the top on top of threaded adjusters you can tune it in very quickly. People often warp their tops by welding too much.

[Rugar]

I just found this on Craigs List. Its 72" X 36" X 1 1/8" thick. I'm going to go take a look at it tomorrow evening to make sure its flat and square. He wants $300 for it. Price seems reasonable compared to what you guys have been quoted. I was wanting to build a 48" X 72" bench, but beggars cant be choosers. What do you guys think for the price? I'm going to try to get it for $250.

[Jack Olsen]

I do most of my welding on a table that's only 1/8" thick. I have a smaller table that's got a 3/8" top. For when I'm pounding and shaping, I have a bench with a 1" thick top.

If you're starting out, I think mot krig is right -- use whatever you've got handy and don't waste a lot of time worrying about it. I also agree with 1-800miner that grinding it perfectly flat is wasted on the same surface you're doing a lot of welding on. You want to be able to weld stuff to the table, sometimes, and then break it loose with a grinder. It won't stay pretty for very long.