Long Hex Key Wrench (12x1pc)

We also list a 12mm ball key, so it is worth being plain about which one you want. The ball end enters at an angle and is a genuine convenience for reaching an awkward screw and winding it in and out. This one is the plain hex, and its whole advantage is that the tip beds against the six flats down its full length. That is the tool you want when a fixing is tight, and it is the one to finish a fixing with. Many workshops end up owning both and using them in that order.

Twelve millimetre socket head cap screws belong to real machinery: press and machine tool frames, large bearing and gearbox housings, conveyor and drive assemblies, hydraulic manifolds and cylinder ends, and heavy plant mountings.

Which raises the question people rarely ask, and it is worth answering because it explains why the size exists at all. Why would a designer use a socket head cap screw here instead of an ordinary bolt with a hexagon head that a spanner or socket could grip? Because the head sits down inside a counterbore, flush with or below the surface, leaving nothing standing proud to catch a belt, a guard, a hand or a passing load. It also lets the fastener be tightened in a pocket where a spanner would have no room to swing at all. The socket recess is not a cheaper way of making a bolt head. It is what allows the fixing to be where it is.

The trade that comes with it is that all the turning force passes through a pocket cut into the head, so how you engage that pocket is the whole game. Bottom the key fully, keep it in line with the screw, and clean the recess out before you start, because a machine screw of this size in a workshop has usually collected swarf, paint or grease in the socket.

It is forged from chrome vanadium and then hardened and tempered.

Buyers are machine tool and plant fitters, hydraulic and pneumatic engineers, engineering and fabrication shops, heavy vehicle and earthmoving workshops, and industrial dealers stocking the sizes above the sets.

Harden's catalogue name puts a carton quantity in the brackets. What we sell is a single 12mm key. Tell us on 94 77 111 8880 whether you want the straight or the ball end and we will make sure you get the right one, delivered island-wide.