MAKITA HSS-Co METAL DRILL BIT SET (COBALT 5% , 5PCS)

Makita HSS-Co drill bits are high-speed steel alloyed with 5% cobalt. The cobalt lets the bit hold its hardness at the temperatures that destroy ordinary HSS, which is why these are the bits to reach for on stainless steel, hardened and alloy steels, and cast iron. Those materials work-harden under a blunt bit and will finish a standard drill in a few holes.

Every option here is a pack of five bits of one size, so you can keep working instead of stopping when one goes.

Sizes available

Listed as Makita code, bit diameter and overall length.

• D-16623 — 2.0 mm, 49 mm
• D-16639 — 2.5 mm, 57 mm
• D-16645 — 3.0 mm, 61 mm
• D-16667 — 3.5 mm, 70 mm
• D-16689 — 4.5 mm, 80 mm
• D-16695 — 5.0 mm, 86 mm
• D-16704 — 5.5 mm, 93 mm
• D-16732 — 7.0 mm, 109 mm
• D-16754 — 8.0 mm, 117 mm
• D-16776 — 9.0 mm, 125 mm
• D-16807 — 10.5 mm, 133 mm
• D-16813 — 11.0 mm, 142 mm
• D-16829 — 11.5 mm, 142 mm
• D-16841 — 12.5 mm, 151 mm

Choosing a size

For a tapped thread, drill the tapping size for the thread you are cutting, not the thread diameter. For a clearance hole, go one step over the bolt size.

On stainless, run the drill slow with firm, constant pressure and use cutting fluid. Letting the bit rub instead of cut is what work-hardens the surface, and once that happens the hole will not take a bit at all.

Buying

In stock at A.C.T. Hardware with free delivery across Singapore, or collect from our showrooms at 645 Geylang Road or 2 Gambas Crescent #03-19, Nordcom Two.