1/4" Hex-Driver Drill Bit (6.0)

The rule that governs drilling, and that almost everyone gets backwards, is that bigger holes need slower speeds. It sounds wrong, because a drill that is struggling feels as though it wants more revolutions. What actually matters is the speed of the cutting edge as it travels around the hole, and the outer edge of a 6mm bit covers three times the distance per revolution that a 2mm bit does. Run them both at full speed and the big one is cutting three times as fast, generating three times the friction, and getting far hotter.

Heat is what kills high speed steel. It does not melt or shatter; it softens, loses its edge in a moment, and then the bit rubs rather than cuts, which makes more heat still. The visible warning is the swarf: a bit that is cutting properly throws off curls or chips in the natural colour of the metal. When they come off blue or straw coloured, the damage is already done.

So on 6mm in steel, drop the speed, use a firm steady feed rather than a light one, and put a drop of cutting oil in the hole. A slower bit under real feed pressure cuts and stays cool. A fast bit under light pressure rubs and burns.

In timber and board none of this is critical, and the bit will run happily at speed.

Six millimetres drills clearance holes for M6 fixings, holes for wall plugs in timber and board, and larger general holes.

M2 high speed steel to DIN338, 135 degree split point, titanium coated, 1/4 inch hex shank.

Buyers are carpenters and joiners, fabricators, electricians, shopfitters, maintenance teams and hardware shops.

Ask on 94 77 111 8880 about cutting oil alongside the bits. Island-wide delivery.