Page 1048 - Tungaloy Catalog

Technical Reference
Drilling Tools
Troubleshooting in gun drilling

Trouble Possible causes Countermeasures
Tighten workpiece clamp
Use non-water soluble cutting fluid
Carry out through filtration of cutting fluid
Cause in machine Reduce spindle run out
Rough finish Verify the feed speed (Vf) is uniform
Reduce clearance between guide bushing and drilling

Is number of revolutions uniform?
Is there an abnormal failure?
Cause in drill
Verify regrinding is correct
Inappropriate cutting condition Reduce the feed rate (f)
Others Remove any packed chips
Reduce clearance between guide bushing and drilling
Verify the feed speed (Vf) is uniform
Cause in machine
Hole accuracy Unacceptable roughness, cylindricity, and oversize Cause in drill Make sure number of revolutions is uniform
Decrease concentrity of guide bushing and spindle
Is there an abnormal failure?
Verify regrinding is correct
IInappropriate cutting condition
Change to machining with standard gun drill
Cause in workpiece Reduce the feed rate (f)
Others Remove any packed chips
Tighten workpiece clamp
Verify guide bushing is not seperated from entry surface
Cause in machine
Decrease concentrity of guide bushing and spindle
Reduced clearance between guide bushing and drilling
Bending of hole Cause in drill Change the shape of guide pad.

Verify regrinding is correct
Reduce the feed rate (f)
Inappropriate cutting condition
Verify there are no faults and unevenness
Cause in workpiece
Verify engaging is not slanted
Technical Reference Change to machining with standard gun drill

14

14–30