Intro: Improving a Welder Ground Clamp
These stamped steel ground clamps are standard from the factory on many welders. They work pretty well, but performance degrades in time. I could buy a nice brass ground clamp, but would rather just improve the contact and current path on this clamp.
Step 1: Fit a Piece of Aluminum Bar Stock
I decided to fit some aluminum bar stock inside one half of the stamped steel spring clamp. My bar stock is 1/8 inch x 3/4 inch. The space inside the stamped steel clamp handle is about 9/16 inch. I used a hacksaw to trim off the excess.
Step 2: Drill a Hole in the Aluminum
Drill a hole through the piece of aluminum for the cable bolt.
Step 3: Cut and Bend the Aluminum Piece
In this photo I have drilled out and removed the rivet that holds the clamp together, removed the plastic handle grip, loosened the bolt, removed the cable, cut the piece of aluminum to length, and bent it to fit the contours of the stamped piece of steel.
Step 4: Build Up the Thickness
I cut a second piece of aluminum to thicken it inside the jaws so it can clamp directly against the steel I am welding.
Step 5: Drill for a Brass Screw
I drilled through both pieces of aluminum at the jaw and the steel of the jaw, used a countersink to prepare the aluminum for a bevel head brass screw, inserted the screw and fastened it with a brass nut. I cut the brass screw end nearly flush with the nut and peened it with a hammer to keep it from coming loose in the future.
Step 6: Inserting the Spring
The spring is quite strong. I did not want to wrestle it back into the handle halves while trying to insert a screw to replace the rivet. I decided to squeeze the spring in my vise and tie it in its squeezed position with some sturdy wire.
Step 7: Assembling the Two Halves of the Clamp
Line up the holes in the two halves of the clamp. Slide the spring into the clamp and insert a screw to replace the rivet so that the screw also passes through the spring. Put a locking nut onto the end of the screw. Make certain one of the plastic handle grips is already on the ground cable. Bolt the cable to the clamp. The bolt now passes through both the steel handle and the hole you drilled in the aluminum.
Step 8: Finish Reassembly
Cut the wire retainer on the clamp spring. Remove the wire with a pair of pliers. Slide the plastic grips onto the spring clamp.
Step 9: Grind Away Steel on the Improved Jaw
Grind away raised portions on the jaw to which aluminum has been added. Here you see I have ground away some of the steel. I may yet grind away the remaining peaks.
Step 10: Getting the Maximum Contact Area
In the photo you can see I did grind away the remaining peaks on the improved side of the clamp (bottom half in the photo). I also filed the screwhead so it does not rise above the aluminum in the jaw at all. And, I have inserted a piece of scrap steel between the jaw and the piece to which the clamp is attached. This makes a pressure point in the middle of the clamp jaw's length that pulls the flat aluminum added to the jaw firmly against the work piece for a broad area of electrical contact. If one were welding on a round tube, it would perform the same function without an added piece of scrap.
The performance of any welder improves with a better ground clamp. This ground clamp now has more surface area to make contact with the work, and it will not rust. If an oxide forms on the aluminum, I can use a file or a little sandpaper to restore a clean finish.