For packing joints.

I made a little baseball bat years ago for that purpose and recently had fun making more different ones for friends.

As you can see I used a piece of rebar for the bat.
I "turned" it using a drill and angle grinder then going through different grains of sanding:

The lightsaber's hilt was made the same way, using a dremel tool to get more control on the details.
The "blade" is made of Corian, a synthetic stone commonly used for countertops.

The sword required a lot more precision to make and ended up okay but looking closely nothing is really symmetrical or straight...
I grinded it from a random stick of metal, the pommel is made from aluminum and the grip is two layers of sewing thread soaked in superglue, sanded, then superglued again.
A cross-guard would have added a lot of character but I didn't find a nice and easy enough way to do it, and I was short on time...