Troubleshooting for Fine Boring

Fine boring heads provide high-precision finishing options for many applications, however, fine boring can be a delicate operation that can go awry. Under certain conditions, it might be necessary to modify or adapt recommended cutting data or tooling configurations of the application. We’ve provided solutions to common fine boring problems to help get you back on the road to productivity.

Need some help with your rough boring? Check out this troubleshooting guide for rough boring.

Problem	Possible Cause	Remedy
Poor Tool Life	Wrong insert grade	Change to higher wear resistant grade
	Excessive speed	Reduce SFM
	Poor cooling of insert	Apply through-tool coolant
	Excessive stock allowance	Decrease depth of cut
Chatter & Vibration	Excessive speed	Reduce SFM, check cutting data tables
	Extreme length/diameter ration	Shorten tool to increase stiffness
		Increase boring bar diameter to larger size
		Change boring bar to carbide or heavy metal
	Wrong insert	Reduce nose radius of insert
	Wrong insert	Use ground geometry inserts (ie: TAN18 grade)
	Incorrect stock allowance	Check cutting data tables
Poor Size Repeatability	Inaccurate tool changes	Worn and/or damaged tool shank; replace
	Inaccurate tool changes	Clean spindle and tool shank
	Variation of stock allowance	Semi-finish with twin insert boring head
	Excessive spindle looseness	Use ground geometry inserts (ie: TAN18 grade)
Unacceptable Roundness	Excessive boring tool imbalance	Change to auto-balance or balanceable head
		Balance tool assembly
		Reduce speed
	Excessive cutting forces	Check stock allowance and feed rate
	Insufficient workpiece clamping	Check for uniform workpiece clamping
	Workpiece non-symmetrical	Reduce cutting forces; change to ground insert
	Workpiece non-symmetrical	Increase cutting speed, reduce feed
Unacceptable Position	Original bore off position	Semi-finish with twin insert boring head
	Excessive stock allowance	Decrease depth of cut
		Decrease insert radius
		Reduce cutting forces; change to ground insert
Poor Surface Finish	Wrong insert radius	Use larger insert radius
	Excessive feed rate	Reduce feed; maximum 25% of insert radius
	Poor chip evacuation	Increase bore to boring bar clearances
		Apply through-tool coolant; adjust nozzles
		Change insert to higher rake angle
		Check depth of cut
Taper	Premature insert wear	Change to higher wear resistance insert grade
		Increase insert radius
		Change from ground to pressed geometry insert
		Increase coolant flow