removing a centre punched screw

[Chris Pink]

I'm taking apart my gearbox because the clutch pack is jammed.

The gear that secures everything together is held on with a tapered 'nut' secured by a countersunk set screw that is centre punched on the edge to hold it (early loctite).

How do I remove the screw (preferably without destroying it) ?

 

[doug748]

You can just turn it out but there is a risk that the screw will be damaged on the way out and the internal thread on the way back in. With care the risk is small, even though you may have to get a new set screw and run a tap down the thread.

Probably safer to drill out the punch mark if you can reach it easily. You only need to tickle it with a small drill, 2mm dia could well do it.

 

[MASH]

The usual approach is to drill it as described above. As he said, just drill out the punch mark and no more. This removes the fused metal that has been holding the screw from turning.