[jfong]

Spot drill a divot for the set screw! Why didn't I think of that.

[DonKes]

Spot drill a divot for the set screw! Why didn't I think of that.

The only problem is if you have to adjust the position of the shaft.

Don

[jfong]

The only problem is if you have to adjust the position of the shaft.

Don

Yes that is true.

[wizard]

Yes that is true.

Very true, you avoid spotting until you have everything properly aligned. The trick with spotting is to avoid going too deep thus weakening the shaft, but yet deep enough to allow the nose of the set screw to seat. There is one advantage to spotting in that it can keep a pulley from walking off a shaft, in other words it holds the pulley axially as well as resists radial movement.

The quick and easy way in the home shop though is to file a flat on the shaft in question. In either case the ideal situation is to have the flat or divot on the extreme end of the shaft to avoid wreaking the shaft. This however isn't possible in many cases thus the goal of minimizing how much material is removed.