Recently I got a nylon mallet for tooling. It was sold as a 14 oz mallet but the head weight is 8 oz. I like it a lot and found the nylon (UHMW, I assume) is a great material for a mallet. I needed a larger one so I got one from Barry King. It's a monster and will do for the larger stuff. Still, I needed a smaller one for very light work like with figure carving where a lot of light taps are in order. I've been using a rawhide mallet for the job but wanted a UHMW one for light work.
I ordered a piece of 1-1/2" round UHMW from ebay. It arrived and it is enough to make three mallet heads. Nice. I cut it into three 2-3/4" pieces and stashed the extra two.
To make a handle, I drilled a 5/16" hole lengthwise through a 7" piece of sledge hammer handle that has been lying around. Although I like a shorter handle, I wanted this one to be a little longer for counter balance. Of course, it wasn't centered exactly so there was an amount of work to grind the thing to roughly a round shape. To do that I ran a piece of 5/16" threaded rod through it and put nuts on each end so I could clamp it in a vice. When it was "round" I chucked it in the lathe and supported the end with a bushing in another piece of UHMW block. Spinning in the drill press, I filed with rasps, files, sandpaper, you name it until it was the desired shape. Then I cut a piece of 1/4" rod the right length and threaded both ends. For the head, I counter sunk the rod and handle so nothing stuck out or looked too home-made. I dyed the handle with leather dye and put a thinned coat of linseed oil on it. For assembly, I put an acorn nut and washer on the handle end and a nylock nut & washer on the head end. It came out good, with a 3 oz head. Perfect for my needs.
For a good visual comparison, here it is with the other two mallets, 8 and 22 oz head weights respectively.