Page 1047 - Tungaloy Catalog

Technical Reference
Drilling Tools
Troubleshooting in gun drilling

Trouble Possible causes Countermeasures
Use the correct cutting fluid
Carry out through filtration of cutting fluid.
Verify the clearance between guide bushing and drilling is not excessive
Cause in machine
Make sure the alignment of the bushing set is correct
Check concentricity of spindle and guide bushing.
Increase tank capacity if the fluid temperature is too high
Short tool life Abnormal wear Cause in drill Verify appropriate guide pad is being used
Verify regrinding is correct
Reduce overall length of drill
Regrind the gun drill when wear is excessive or check tool life details
Reduce the cutting speed
Inappropriate cutting
Reduce the feed rate
condition
Reduce fluid pressure
Cause in workpiece Check to make sure the material quality is uniform
Verify the shape of the bushing is correct
Verify the feed speed (Vf) is uniform
Cause in machine
Make sure number of revolutions is uniform
Chip packing Inappropriate cutting Use proper feed rate (f)
Enlarge chip box

Use the correct amount of fluid
condition
Chip control Cause in workpiece Change to machining with standard gun drill.
Change the shape of cutting edge so that cores become small .
Check to make sure the material quality is uniform
Use cutting edge that is not broken or chipped
Cause in drill Make sure outer corner is free from excessive wear

Chip entanglement Inappropriate cutting Use the correct feed rate (f)
condition
Cause in workpiece Make center hole as large as drilling diameter or smaller than it. Lower fluid
pressure.
Technical Reference

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