More than a year ago I bought six new 6″ bar clamps that were on sale for a pretty good price. The clamps work well and I only have one complaint: the handles are too small to grip properly. I also have several 12″ bar clamps that have the same problem, and in an attempt to improve the handles on those, I dipped them in Plasti-Dip – a product that is supposed to make a coating that thickens and provides a better grip. It was expensive to buy and the results were just marginally better, so I would consider it a waste of time, money and effort.
Another option would be something like hockey tape, to wrap the handles with. Ultimately, I abandoned this idea, thinking that eventually it would start to unwrap and get sticky.
I figured the best fix would be to replace the handles completely with bigger one. Then it occurred to me that I could just make a new handle that would fit over the old one and solidly glue that in place. The fact is, as I have so many things happening at this time, I can’t really afford to spend a lot of time on this – it would have to be quick and effective.

I rounded up all of the clamps in the workshop:

There are probably two or three more of the 12″ clamps around, either in my house or in the shed, but this is enough to start with.

The first thing I did was to make a hole in a scrap of wood to test the fit of the handles. I didn’t want to do anything to the old handle to get it to fit, like sanding or cutting it down – it would have to slip in easily.
I determined that a 7/8″ hole fit perfectly for the 6″ clamps, and a 15/16″ hole was pretty good for the 12″ ones:

For the material, I just grabbed an old 2×4 to cut the handles from. I ripped it in half, then cut the parts down to 1-1/8″ square.

With a stop block set up in my miter saw, I cut them to 4″ long:

I managed to get seventeen handles from the 2×4, after cutting out the bigger knots and other defects.

To set up the drill press, I marked the centre on the first handle:

Then drilled out eight of the handles with the 15/16″ bit. I figured it would be handy to have some extras if I find more clamps, or buy more with that size handle.

The remaining nine were drilled out with the 7/8″ bit. Again, a few extra in case I get more of these clamps:

To shape the handles, I used my disk sander. The best grip for me is to have it square, with rounded corners, so the shaping is minimal:

With the handles made, I can glue them onto the old ones. I’m using polyurethane construction adhesive for this, since it is very strong and have great gap filling properties. I’m not doing anything to the old handles to improve the adhesion – not removing the paint or the Plasti-Dip, or roughing them up. I figure the large contact area will be enough to ensure a good hold.

With some on the old handle, I squeezed some into the hole in the new one:

Then twisted the two together, to spread the glue evenly.

With all of the handles glued on, I lightly clamped them to the edge of my router table to dry. Having them upright like this takes away the possibility that the new handles will slide off, since the glue does take a long time to cure.
I gave it overnight to dry, to reach the glue’s maximum strength:

The next day they are ready to use. Originally, I was going to drive a pin through the handle to increase the strength, but I think these will be fine as they are. I’ve glued lots of handles onto threaded rod with this adhesive and never had a failure.
A quick, easy and very effective fix for these inexpensive clamps, it took less than an afternoon to install the new handles.

The project is detailed in this video: