Re-machine surface on a 5 feet square Acorn welding table, Greenville, SC.

[Overland]

Seems like they tried to fix a badly worn table, but didn’t completely.

 

[Overland]

Use a 9" grinder and a larger cup wheel, 6" dia or so, hold it flat to the surface and have at it. The cast iron will grind easily so make sure to get a good feel for before you get down to the good surface level. In other words grind in passes over the entire high area a little at a time with each pass, DO NOT start at one end and grind down to full depth and then go along the length at that depth.

Was thinking something like that, but whenever I've tried to grind cast iron it was very slow. Is there a particular type of wheel grit I should get ?
Bob

 

[EPAIII]

OK, an idea.

Use angle grinder to remove those fences/rails.

Then weld a new, FLAT sheet of of steel on top. I don't know how thick it should be. 1/4"? 3/8"? 1/2"? 3/4"? More? Perhaps others can suggest.

Edit: I just looked at the photos. I guess some holes would need to be cut in the new top. A lot of work. Perhaps not the best idea.

On the other hand, perhaps the holes provide places where the new top can be stitched down all the way across the table.

 

[Overland]

One thought I had was to get a bench grinder, and mount it, upside down, or on its back, so wheel extends past the motor, and mount that on a sled. I could put some weight on it, and the rails/sled would limit depth of cut.
I don't see how I could control a milling cutter in a simple sled without it bouncing all over the place.
Many years ago I saw a vertical spindle surface grinder. Imagine a base and post, like a table top drill press. The motor was mounted on an arm so it could rotate and the post was threaded so a simple nut could set depth of cut. That could work with a cup wheel and maybe a 1 hp motor.
Bob

 

[Overland]

One wonders why you bought it like that if you don't know how to fix it.

You could do some preheating and try to build the low areas back up.

But my vote is to cut a piece that pretty much fills the void. Then use it with or without your filler piece. I'm guessing you'll either learn to live with it or you'll get sick of it and find another fool.

Sometimes you take a risk at an auction, based on the poor photos listed...........
It's still useable until the raised edges get in the way.
Bob

 

[Homeshopblob]

Weldsale does it, and I believe they are affordable, but they are in PA.

 

[EPAIII]

It's a welding table, not a surface plate, so...
Another idea:

* Roughly level the table first.
* Four piers, resting on the floor at the four corners.
* Two 7 foot lengths of pipe on opposite sides and supported by the piers. Set them level and/or parallel to table top to begin.
* Sleds on each side hold two more lengths of pipe at 90° to the first two with wheels riding on the first two. Some kind of improvised brake would be needed to hold the sleds in place for a pass.
* A heavy duty grinder with a cup wheel is mounted vertically on a carriage that rides on the second pair of pipes.
* You can use shims on the corner posts which are removed or rearranged to set the depth of the "cut".
* A length of cord or cable is used to move the grinder across the table. Precision is not needed, just a constant, slow speed.
* Set the grinder to start with the high spots and traverse the table in an X-Y pattern. Lower the rails and repeat until done.

Grinding does not require a lot of pressure or create a lot of force so the above should work. If you have the grinder this will probably cost $200 to $300 or so. But, even with your time included, it is probably less expensive than having the job done. And if you need to buy the grinder, then you have a nice new tool for your shop.

I would be tempted to automate the motion of the grinder in that X-Y pattern. Sitting there and cranking it back and forth is gonna get very boring. Gear motors and limit switches should do it. You can do other things while a pattern of passes is completed. If this is a commercial shop, you probably save enough of your time to pay the extra for the automation.

 

[EPAIII]

If you do it yourself, you can get cheap shower curtains at dollar/thrift stores. Get four of them and hand them around the table while grinding to control the dust.

I buy then by the half dozen for $1 each and use them in the shop for many things.

 

[Garwood]

That is a rough table. I wouldn't fix it.

If you do though I would suggest not trying to grind all that. You're talking about removing 50 lbs of cast iron with a hand grinder. That sounds like a terrible idea. Pay to have it done or move on IMO. Life is too short to mess with junk like that sometimes.

What's a nice one cost? $1200?

 

[gbent]

If it was mine I'd pay to take it to the Blanchard. The big machines would eat that in less than 15 minutes of spindle time, the rest is all handling.

If time had little value to me, I believe I would make a sled to use my 2 x 72 belt grinder and grind under a contact wheel. Those 24 grit belts will really move metal and with a proper sled you could easily get it to within welding table flatness.

The picture of the rail showing how much the table top was worn is interesting. I've never seen a table with that much wear. My guess is when they set it up on their boring mill they either ran out of travel, or didn't want to reset the clamps.

 

[Ohio Mike]

You can get a 5x5 for around $1500 here in the midwest.

 

[Bill D]

I woulD leave one side as is and only grind off one of the raised sides. Like Limi says a straight edge is useful for clamping stuff down and keeping it aligned.
Bill D

 

[Bill D]

Maybe bolt a radial arm saw to the casting and use a grinding wheel instead of a saw blade.
Bill D

 

[Strostkovy]

That table looks awful and a lot of these ideas are ridiculous.
You have a new outdoor grinding and torch cutting table. It's not worth putting any work into it. Honestly it's not even my top choice for a welding table even if it was ground flat.

 

[Milacron]

FWIW, Continental Field Systems in Savannah has a huge planer mill that would easily handle that job..

 

[Rob F.]

Is that table the same thickness or are the edges thicker? If all one thickness what does the bottom look like, maybe you can just flip it over?

Decent platen tables here in Ca are $2500 ballpark.

 

[Overland]

You can get a 5x5 for around $1500 here in the midwest.

I'm very surprised you'd say that from what I've seen.

 

[Overland]

If it was mine I'd pay to take it to the Blanchard. The big machines would eat that in less than 15 minutes of spindle time, the rest is all handling.

If time had little value to me, I believe I would make a sled to use my 2 x 72 belt grinder and grind under a contact wheel. Those 24 grit belts will really move metal and with a proper sled you could easily get it to within welding table flatness.

The picture of the rail showing how much the table top was worn is interesting. I've never seen a table with that much wear. My guess is when they set it up on their boring mill they either ran out of travel, or didn't want to reset the clamps.

The guy at Sullivans said grinding cast iron very slow. He was thinking 3 to 4 hours at $400 an hour on his Blanchard. Economics don't make sense to me.
Bob

 

[Overland]

Is that table the same thickness or are the edges thicker? If all one thickness what does the bottom look like, maybe you can just flip it over?

Decent platen tables here in Ca are $2500 ballpark.

Somebody's thinking - "might could work", as we say in the South.
Seems to be same thickness, as square holes are square full depth.
It's sitting on a pallet on my trailer now. I'll check it out tomorrow.
Bob
Edit, it was next to a big Gray boring mill at the auction site. I think it would have fit on the table, oh well.

 

[reggie_obe]

Maybe bolt a radial arm saw to the casting and use a grinding wheel instead of a saw blade.
Bill D

Radial arms saws have all the rigidity of rubber in the vertical direction, bad idea.