Enter the ‘Hartmetall-Spiralbohrer’.

I am using some Carbide Twist-drills (Busch 203HM) to see if they work better than ‘ordinary’ twist-drills for use with stainless steel. These drills are made by the German manufacturer Busch who probably supply the majority of jewelers with tool steel twist-drills and burs. http://www.busch.eu

The Carbide Twist-drill are designed for use with hard metals such as 18 ct white gold and what Busch call ‘jewelry steel’ which I assume is stainless steel. Busch also make a high speed steel twist drill which can be recognized by the black shank but the carbide version promises to outlast both tool steel and high-speed steel versions. These twist-drills are distinctive as they have four grooves in the fluting of the drill that Busch say makes chip removal easier and reduces breakage.

Recommended drilling speed
Free-hand 5,000 – 9,000 r.p.m.
Drill press 8,000 – 14,000 r.p.m.

Busch also suggest to,
Center punch where you want to drill.
Use a coolant to increase the lifespan of the twist-drill.

Busch 203HM Carbide Twist-drills come in 0.1 mm size increments from 0.70 mm to 1.60 mm.

Final note: these twist-drills are a good deal more expensive than tool steel twist-drills. I bought mine for $15 au EACH plus GST. However I have been going through the tool steel twist-drills like they were ‘going out of fashion’ so if the carbide ones live up to their promise to last longer they may be more economical for working with stainless and white gold. You could of course turn up the juice on the laser welder and burn the holes in to your job but it is nice to be able to drill them at the bench.

So how good are they? Well its not a magic bullet for stainless but I suspect stainless is a problem anyway. They do perform better than a standard twist drill, cutting more positively and less problems with pushing up a burr on the back of the piece being drilled. This can be a big problem with thin material especially if you need some pressure to get the drill to cut as you might with a standard twist drill. I got best results using the drill press and I did break one drilling ‘free-hand’ i.e. with a hand-piece/flex drive. Yes, you will cry when you break one after only drilling a couple of holes (see the previous paragraph) however, with care and following the recommendations I think they are a step up for working with stainless steel. I suspect that they will be brilliant in precious metals like 18 ct white. They do need care drilling freehand as they are more brittle.