HSS Drill Bit

HSS twist drill bits sold singly, from 1 mm to 25 mm: half-millimetre steps up to 13 mm, larger steps above that, plus 3.2 and 4.2 mm. For steel, aluminium, plastic and wood.

Drill steel at a low speed with a drop of cutting oil, and ease off as the bit breaks through. Running fast and dry overheats the tip and blunts it quickly.