Building a Welding Fixture Table

The importance of a good work surface

When I was preparing to start writing this column I attended the Fabtech Expo in Chicago. Among other things I was looking at fixture tables. Most fixture tables are extremely heavy and fairly expensive. On the second day of the show I stopped at a booth and found the Fab Block from CertiFlat. I knew right away I needed to put one in my shop. To me, having an ample and clean workspace is very important. Before I start a job I make sure all my tools are put away, my work surfaces are clear, and the floor is swept. The feeling of starting fresh before every project allows me a stress-free environment to be creative and to do my best work. While mid-project I’ll stop to clear my head by putting away tools, cleaning work surfaces, and sweeping the floor again. The freedom to work uncluttered is something I always strive for.

how to build a fixture table

For my new fixture/welding table I contacted CertiFlat through its parent company Tab and Slot and got a 2 x 4-foot Fab Block and Leg with casters kit headed my way. I received all of the pieces and hardware via UPS in three boxes. Here you see all of the laser-cut plates, casters, and hardware.

Words and Photos: Big Joe

how to build a fixture table

I decided that I wanted to assemble the leg kit first so that when the assembly of the Fab Block was complete I would have a place to mount it right away. Here you see all of the leg components.

Words and Photos: Big Joe

how to build a fixture table

As the name Tab and Slot implies, everything in this kit is assembled easily using—you guessed it—a tab-and-slot assembly. The laser cut on all of the parts is very clean. Everything has a fairly tight tolerance, and I found during assembly of the leg structure I needed the use of a mallet to lock these pieces into their final position before tack welding them into place.

Words and Photos: Big Joe

how to build a fixture table

I first assembled the four individual legs and their corresponding mounting plates. Be sure to dry fit all of the leg kit components before you start welding. The mounting plates on both ends of the legs do have a proper orientation to make sure your final assembly goes smoothly.

Words and Photos: Big Joe

how to build a fixture table

Next I used the top plate of the Fab Block to get the proper spacing of the legs and assembled the cross members. After tack welding all of the tabs and joints I finished welding them. I was sure not to weld in one spot too long to reduce heat buildup and the potential to pull any corners out of square.

Words and Photos: Big Joe

how to build a fixture table

The final step of the leg assembly was to bolt on the included casters. They are nice, fairly heavy-duty casters with a dual locking mechanism. Not only do the wheels lock to prevent the table rolling, but the casters also lock in place preventing them from rotating on their bearings as well. This makes for a nice secure work surface when all four wheels are locked into position.

Words and Photos: Big Joe

how to build a fixture table

Next was the assembly of the support structure of the Fab Block itself. This assembly process is done working with the block being built upside down. This process can actually be done anywhere you have ample space to work around the table as it’s being assembled. During the initial assembly of these pieces you don’t need to concern yourself with things being level or square. The precision cut of the components make for a very accurate fit, and all the parts pretty much square themselves up. The use of a mallet or hammer can be expected to get some parts to completely seat into one another. If any parts appeared to have too tight of a fit I dressed the edges with a bastard file, which resolved any fitment issues I encountered. Here you can see the inner structure of the Fab Block. Again, the tab-and-slot construction make this assembly idiot-proof, as it will only go together only one way as it squares itself up.

Words and Photos: Big Joe

how to build a fixture table

Once the side places and leg mounting plates are snapped into place the Fab Block really takes on its mass and appearance. This is the point when I got really excited about what I was building.

Words and Photos: Big Joe

how to build a fixture table

Now is the point when you do all the work to make sure your completed work surface is as flat and true as it can be. Not only do you need to secure all of the components together for the welding process, but you also need to draw them together tight to create the flat surface. This can be done with any secure clamping method that works for you. C-clamps and bar clamps are acceptable if you have enough large clamps to do the job. I opted to bolt the entire table together, which made it easy for me to manage and move around during the welding process. Once all the parts are together the table gets to be quite heavy, and moving it by myself with a bunch of clamps would have been next to impossible.

Words and Photos: Big Joe

The table is 6 inches thick, and the holes in the table are 5/8-inch. I used 8 x 1/2-inch coarse thread bolts to clamp through the table. I used half-inch coarse thread Ready Rod or All Thread to secure my table laterally through the sides, and it worked very well.

Once the entire block is bolted together “snug” I placed it on a set of saw horses and got out my straight edge. By tightening and loosening bolts where needed and the occasional persuasion of a heavy hammer, I was able to true the work surface so that it was flat across front to back, side to side, and diagonally across the entire surface. You do not want to rush this step. The more time you take here to ensure your surface is flat the happier you’ll be when it is finished. All the prep work pays off when the welding is done. While truing the surface I had a couple of spots that I needed to add bolts to draw down a couple of high spots, so I was happy with how flat the block was.

how to build a fixture table

To weld up this table I used a 220V MIG welder. The entire table is constructed of a 1/4-inch steel plate, so it takes a fair amount of heat to get good penetrating tacks and welds. There were approximately 150 tabs and slot points that needed to be welded on my table. That will vary depending on the size table you’re assembling. I tack welded all the tabs before laying any full welds. I jumped around the entire block, tacking top to bottom and side to side to dissipate heat as much as possible as to not distort the block I had worked so hard to make flat. Once all of the tabs were tacked I checked with my straight edge to make sure the surface was still flat. It was, so I proceeded to go back and finish weld each of the tab and slot points. Once again, I worked back and forth around the block to dissipate the heat equally as much as possible. This is another part of the process in which you will be happiest if you don’t rush yourself.

Words and Photos: Big Joe

how to build a fixture table

Once the block had cooled, I removed all of the bolts and secured the block to the leg structure. I had taken my time to make sure the surface was as true as possible all along the process. The payoff was a finished work surface that is as true as I could ever need. I’m excited to put it to use!

Words and Photos: Big Joe

For the time and money investment I don’t think you can go wrong here. It’s perfect for any small fab shop or home work shop. There are lots of “off the shelf” sizes available and custom sizes are available as well at weldtables.com. Tell them that #HotBikeSnapFab sent you!

If you have any questions or suggestions for the column you can reach me at [email protected] Cheers!

Browse our Tech section for more how-to stuff.