Runout, HSS drills and dowel holes

[Davek0974]

Relative to the job - 0.1mm is fine for a hole that is to be tapped, for dowel holes, they must be reamed to fit.

Drills are only ever treated as a way to get an approximate sized hole, the accuracy is added later by machining or reaming or boring etc.

If the spot-drill is used correctly then the drill can be quite bad and still drill in the correct place.

[Robin Hewitt]

Collets come in different tolerances. If your vender does not mention tolerance you can probably assume they are from the cheap end of the pile