HSS Straight Shank Twist Drill (17.0mmx1pc)

A drill bit applies torque to whatever it is cutting, and that torque grows steeply with diameter. A 17mm bit in steel is generating enough turning force that any piece of material not firmly held will be snatched out of position and spun. If it is a bracket or an offcut of plate, it becomes a blade turning at drill speed, and hands, forearms and faces are exactly where it goes. Serious injuries in workshops come from this far more often than from the bit itself.

So clamp the work. Properly, to a bench or in a vice, not held with one hand while the other holds the drill, and not resting on a knee. If the piece is too large to clamp, clamp something to it that will jam against the bench when it tries to turn. A piece of steel held only by its own weight is not held.

The moment of greatest risk is breakthrough, when the bit is about to exit and the last thin web of metal gives way. That is when it grabs, and a workpiece that was behaving perfectly for the whole hole will let go in an instant.

Wear eye protection, keep sleeves and anything loose away from the chuck, and never wear gloves at a pillar drill, because a glove caught by a rotating bit takes the hand with it.

Seventeen millimetre holes in steel are for bolt clearance, structural and bracket fixings, plant repairs and heavy fabrication.

M35 cobalt high speed steel; the spec's carbide and percussion lines belong to a masonry bit and do not apply here.

Buyers are fabricators and welders, structural steel shops, engineering and machine shops, plant and heavy vehicle maintenance.

Ask on 94 77 111 8880 about clamps and machine vices alongside the bits. Island-wide delivery.