Here's a tech tip from Jay at Special '79 to help fellow Cultists hone their metal butchering chops. Making your own T-dolly will help you build a variety of fabricating skills and add a useful tool to your garage. T-dollies can be used for many hammering/bending scenarios, but Jay uses his T-dolly to create small, uniform radii along the edge of sheetmetal.
There isn’t much to the anatomy of this useful tool: just a piece of solid steel rod and some thick steel bar. For this exercise, I used the following materials and tools:
Materials: 10” long piece of 7/8” diameter mild steel solid rod; 2-½” x 6” x ½” thick mild steel bar
Tools: Metal files, 4-½” angle grinder with cut-off, grinding, and flap wheels; MIG welder
First step is to clean up the ends of the 7/8” solid rod a bit. You can choose to just take the hard edge off or go wild and round them off nicely. I used my lathe to shape the ends but it’s pretty easy to tackle the job with the angle grinder and assorted wheels. Once you have them done, it’s time to prep the piece of 2-½”x 6” x ½” bar. I cut my piece out of some ½” plate that I had using the angle grinder, a cut-off disc, and some patience. Clean up the sharp edges and do some extra chamfering along the edges you’re going to weld to the solid rod. I use a simple 110v MIG welder to tack the bar to the rod on each end and then lay some beads all the way around. On something like this, I crank the MIG up to the max amp level to ensure plenty of weld penetration. You can choose to leave the weld as is or practice blending the weld with a flap wheel and angle grinder. Now you have a T-dolly in your tool box.
For a simple t-dolly exercise we’re going to flare two pieces of 16ga sheetmetal to create a peak to weld. Start by cleaning up two edges of the sheetmetal so they fit together nice and straight. Clamp your new t-dolly in a sturdy vise and place the first piece of sheetmetal long the top of the T-dolly with the edge hanging over the dolly a bit (see photo). Using a body hammer with a smooth, flat face. start hammering the metal from one end to the other, moving it down against the radius of the T-dolly. Visually check the radius and hammer where needed to smooth out the entire length. Do the same to the second piece of sheetmetal.
After both pieces are hammered to your liking, lay them on a flat surface to check the fit, making sure there are no gaps present. I use a TIG welder on the sheetmetal, but you can do this exercise with a MIG welder turned down to the lower amp setting. Tack the peak in the center first and then close to the ends of the seam. Weld up the entire seam and let cool. Practice more with the flap wheel/angle grinder combo by first smoothing the top of the weld bead, then each side to create a nice even finish. Practice this with more welded peaks to really get the hang of the whole process. This concludes this little nugget of tool making and metal forming knowledge.
Keep on butcherin’
See more of Jay's work at Special '79