Solid Carbide Boring Technical Support

Formula Name
Surface Feet per Minute (SFM)	SFM = 0.262 × Tool Diameter (in) × RPM
Revolutions per Minute (RPM)	RPM = 3.82 × SFM ÷ Tool Diameter (in)
Inches per Minute (IPM)	IPM = Feed per Tooth (FPT) × Number of Teeth × RPM
Meters per Minute (M/min)	M/min = SFM × 0.3048
Millimeters per Revolution (mm/rev)	mm/rev = Inches per Revolution (IPR) × 25.4

Feed and Speed Chart

Material	HB/Rc	SFM: Uncoated	SFM: AlTiN+	Feed IPR	Tool Diameter .015-.045	Tool Diameter .050-.100	Tool Diameter .110-.160	Tool Diameter .180-.230	Tool Diameter .290-.320	Tool Diameter .360+
Cast Iron	160 HB	75-200	200-550	.0005-.010	0.006	0.008	0.010	0.014	0.020	0.031
Cabon Steel	18 Rc	75-200	200-450	.0005-.007	0.003	0.005	0.006	0.008	0.012	0.017
Alloy Steel	20 Rc	75-200	200-425	.0005-.007	0.003	0.004	0.005	0.007	0.010	0.015
Tool Steel	25 Rc	75-175	175-300	.0005-.005	0.002	0.003	0.004	0.006	0.008	0.012
300 Stainless Steel	150 HB	75-175	175-350	.0005-.005	0.003	0.003	0.004	0.006	0.008	0.013
400 Stainless Steel	195 HB	75-210	130-420	.0005-.005	0.002	0.003	0.004	0.006	0.008	0.012
High Temp Alloy (Ni & Co Base)	20 Rc	50-130	130-300	.0005-.004	0.002	0.003	0.003	0.005	0.007	0.010
Titanium	25 Rc	50-120	120-275	.0005-.005	0.003	0.004	0.005	0.006	0.009	0.014
Heat Treated Alloys (38-45 Rc)	40 Rc	50-100	100-200	.0005-.005	0.002	0.002	0.003	0.004	0.006	0.009
Aluminum	100 HB	75-250	250-750	.0005-.015	0.011	0.015	0.019	0.026	0.038	0.056
Brass, Zinc	80 HB	75-300	250-650	.001-.010	0.009	0.012	0.015	0.021	0.030	0.045

SFM = Surface Feed per Minute DOC = Depth of Cut IPR = Inches per Revolution

These parameters serve as initial guidelines; actual performance may vary based on factors such as
length-to-diameter ratios, setup configurations, and machine rigidity.

Troubleshooting Common Problems

Browse Solid Carbide Boring Tools

Problem	Cause	Solution
Rapid Flank Wear	Cutting Conditions	Check for excessive feed and speed. See above chart for recommendations.
	Tool	Select a coated tool.
	Part	Make sure prior operation did not work harden the metal.
Built-up Edge	Tool	Select a coated tool.
	Cutting Force	Check for excessive feed rate (IPR). See above chart for recommendations.
	Heat	Use an SCT coolant holder. If coolant is not available, use shop air and a coated tool
Corner Breakage	Cutting Conditions	Check for excessive feed and speed and depth of cut. See above chart for recommendations.
	Tool	Select a tool with a radius. A radius is stronger than a sharp corner.
	Part	Check the drilled hole.
Surface Too Rough	Cutting Conditions	Check for excessive feed rate (IPR). See above chart for recommendations.
	Build-up Edge	See above (Built-up Edge).
Chatter	Set-up	Set tool above center. Reduce the overhang ratio. Clamping length should be at least three times the boring bar diameter. Change the speed of the machine. Speed change may break up harmonics and reduce chatter.
	Boring Bar	Select the largest diameter boring bar that will bore the required diameter.
Taper Smaller in Back	Chip Packing	If the boring bar is too large to allow chips to evacuate, then the chips may pack on the tool and cause the bar to deflect away from the bore.
	Program	If the taper is consistent, then the program can be altered to bore a taper in the opposite direction resulting in a straight hole.
Taper Bigger in Back	Cutting Forces	Reduce forces. Deflecting bar below center causes the hole to become larger.
	Built-Up Edge	Built-up edge will cause the hole to become larger until the built edge breaks off, then the hole becomes smaller.
	Program	If the taper is consistent, then the program can be altered to bore a taper in the opposite direction resulting in a straight hole.

Contact the SCT Engineering Team

Cutting Feed & Speed Rate Formulas

Use the following formulas to calculate cutting speeds, feed rates, and conversions for optimal machining performance.

Be sure to verify tool and material compatibility for precise and safe machining operations.
For further assistance, contact our technical support team.