In the US most woodturning/woodworking supply stores carry kits. In this case I took the guts from a Harbor Freight screwdriver, turned a new handle out of cherry, filling the cracks with colored epoxy, made a ferrule from a brass plumbing fitting, and put it all together. The handle is finished with Danish oil.
I’m more into metalworking and I’m not that good with wood, but I’ve made quite a few handles for files and other tools. I’ve used boiled linseed oil for finishing mostly because that was what I had but the handles get dirty and ugly almost instantly. Is Danish oil better in that regard or would you recommend something else for oily/greasy use? Oh, and your handle looks way better than mine, I need to step up my wood game. 😀
The only difference with the Danish oil is the addition of some varnish. Apply enough coats and it’ll start to build up and might help a little with stain resistance. Otherwise you would need something more durable like a film finish. I think maybe laquer or a CA finish would work well for oil/grease resistance.
Some people don’t put any finish on handles and let natural oils from their hands build a patina. If you don’t like the look then some kind of film finish is probably what you need.
I just try different handle shapes until I find ones I like.