HSS Straight Shank Twist Drill (3.5mmx2pcs)

Before anything else, an honest note about the catalogue entry. The spec for these carries two lines that do not belong to them: a reference to a heavy duty carbide tip and a reference to percussion drilling. Neither is correct for this product. A carbide tip and hammer action describe a masonry bit, and hammer action used on a twist drill in steel destroys the cutting edges immediately. What this actually is, and what the rest of the spec and the name confirm, is an M35 high speed steel twist drill. We have written the page for what it is rather than repeating a line that would cost somebody a bit.

M35 is high speed steel with roughly five percent cobalt in it. The cobalt does one specific thing: it lets the steel hold its hardness at higher temperatures. Ordinary high speed steel softens as the tip heats, and once soft it stops cutting. Cobalt steel keeps its edge where plain HSS gives up, which is why it is the standard answer for stainless steel, for hardened and alloy steels, and for anything that heats up quickly because it resists being cut.

The cost is brittleness. Cobalt steel is harder and less forgiving, so it chips if the bit is allowed to chatter, if the drill is wobbled, or if the work is loose. Firm mounting and a steady hand matter more with cobalt than with a standard bit.

At 3.5mm you are drilling small holes in stainless sheet and section, fabrication and bracket work, food and marine equipment, and steel that has already blunted something else.

Buyers are stainless fabricators, general engineering and fabrication shops, marine and food equipment trades, maintenance fitters and hardware dealers.

Message 94 77 111 8880 and tell us the material, and we will confirm cobalt is what you need. Delivered island-wide.