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USER GUIDE
GUNDRILLS
When using a gundrill on a lathe machine, a Drill Penetration Instructions
short solid carbide centering drill should be
used prior to the gundrill. Once the gundrill 1 Rotate the drill counterclockwise prior
enters the pre-drilled hole, it is self-guided. to and during hole penetration
1 Drilling a pre-hole (drill diameter +.0008”)
2 Stop the drill rotation and start the coolant
Never try to penetrate the workpiece by using a gundrill
3 Rotate the drill clockwise prior to drilling operation
2 Gundrill penetration through the pre-hole
The Influence of a Tool Vs. Workpiece Rotation
A shallow pre-hole will not guide an unbalanced gundrill Rotating tool Rotating Rotating tool
workpiece & workpiece
2 x D min
Worst Medium Best
The maximum misalignment between the drill bushing
and the workpiece center line should not exceed .0008”.
Rotating Workpiece
Bushing
Stationary Drill
Max.
0.02 mm
.0008"
359
