Powdered dye concentrate soluble in turpentines and citric terpene. These are very powerful dyes and a little goes a long way. Smaller quantities available packed by volume in reusable, laboratory rated, storage containers with an internal sealer...
Austrian made, tool steel bit with dual rim lips and wide chip gates which don't bind up. These cut a hole as cleanly as forstners and are easier to hone and sharpen.