Well, the walnut I got from a turkish dealer, called "turkishwalnut" on Instagram. Very tight, wonderful curly grain, but not cheap. A year ago I bought a bigger piece that will serve for a 12 handles.
Rough shaped with a rasp, later a finer metal file, followed by sand paper, grain 180, 280, 360, 400, 600, 1000, 1200 and 2000.
Between you need to wetten the wood and dry it with a heat gun so small splinters will raise and get cut on the next sanding.
After the 2000 paper I polished with rotton stone powder.
Now you need to stain it with red root oil (I got these from "the London finisher", formerly working for Purdey) till you get the depth and colour you want.
Polish again with rotton stone..
Now the slacum oil, some drops on the handle and move it all over, it will cure quite fast, if it gets tacky, rub it in with your palm, between layers, polish with rotton stone.
I think I used a 10 layers, once I came across a tiny hole that couldn't get filled so I sanded this part again (better to do this BEFORE ;)) and filled it...
After the final layer, a thin layer of kit oil.
The slacum needs to dry for about 4-8h better leave it over night.
If you don't wait till it's 100% cured and apply the lext layer, you can risk that the surface get's tiny bumps and you'll need to repeat the polishing etc.