Simple SDS drill adaptor.

Like most people these days my big hammer drill is an SDS type. Consequently just about all of my masonry drills are of this fitting, even the cheap ones these days are well made and last a good long time for the DIY'er.
However not all jobs require such a big heavy drill, quite often my 10.8v combi drill is plenty enough power to put in a small wall plug for a picture or a light shelf.
The 10.8v combo drill like many others has a 13mm (1/2") chuck on it, which will not grip an SDS drill bit. Rather than buy another set of masonry bits I turned this simple little adaptor.
It is nothing more than a bushing made of brass, the external diameter being just 13mm so it is an easy fit in the drill chuck, the internal diameter bored to be a sliding fit on an SDS drill bit shank. It was then split with a hacksaw.
To use it couldn't simpler, put the collar in the chuck with the split between two of the jaws, slide in your SDS bit and then tighten the chuck.

I recommend Brass for this project, it turns nicely, won't rust, is quite "grippy" on the SDS shank but resists burring or galling. Aluminium would be a poor choice for the reasons mentioned, steel would be fine but brass is best I think, and it only requires a small piece of 1/2" stock. I also recommend you test a few different drill shanks, they can vary by brand but at most by 0.1-0.2mm, so don't go for too tight a fit.

The shoulder you see is not essential on reflection, but not bad either. 10minutes on the lathe and a scrap of brass saved me a heap of money buying 2 sets of masonry bits or a cordless SDS which I really do not need.