August 27, 2015

How to fix and improve cheap bar clamps

Simple trick to fix cheap clamps.
When I go to the DIY center I always buy a couple of these very cheap bar clamps, so now I have a lot of them. These clamps are so cheap that one may wonder if they are worth what they cost. I would buy high quality clamps if I could afford them, but for the moment I always used these in my woodworking projects. The only problem I always had is that these clamps can leave a big mark in the workpiece if I don´t use some blocks to protect the wood.

Cheap clamps: old model and new model.
Horrible mark cheap clamps can leave in the workpieces. woodworking.enredandonogaraxe.comThe old model has a solid piece hooked on a metallic ball in the end of the threaded rod. It doesn´t mark the wood too much, so it is not absolutely necessary to use blocks to protect the workpiece. But the new model has that simple piece of metallic sheet in the end of the threaded rod, and that sheet leaves an horrible mark in the wood. But the simple solution I show in this article makes this cheap bar clamps very useful in our homemade woodworking shop.

How to cut the slot in the plywood pieces.
Sanding the edges with a disc sander. woodworking.enredandonogaraxe.comWe only need to cut a strip of 1 centimeter thick plywood in a lot of 10cm long by 3cm wide pieces. We need two pieces for each clamp. I made 20 pieces, to fix and improve 10 clamps. Now I put a 5mm drill bit in the drill press, to drill three holes in all the pieces. With a chisel I cut the wood between the holes. And then, to clean the wood inside the slot, I use the drill bit spinning inside the slot while I move the pieces from side to side. I want to make a slot that is big enough to insert the metallic bar of my clamps, but I don´t want it to be neither too loose nor too tight. I sand the edges of all the pieces in my disc sander, and they are ready to use.

Grinding the notches and the rivets.
I also need to take the moving jaws apart, so I have to grind the notch (or in some clamps the rivet) these clamps have in the end of the metallic guide. It is an easy task. I only have to make sure I don´t have any paper or sawdust near, because the grinder makes a lot of  sparks and I don´t want to make fire.

Moving jaws with misaligned threaded rod..
This trick has another advantage, because now it is easier to apply the pressure in the right direction, parallel to the metallic bar. The problem was that sometimes the nut in the moving jaw is misaligned, but once we have installed these pieces of plywood, they have enough play to correct the direction of the clamping force.