Indexable Boring Technical Support

If you’re using CBN or PCD inserts, click here instead.

Speed and Feed Chart

Material	HB/Rc	Uncoated SFM	AlTiN+ SFM	Maximum DOC for ACD & ATD	Maximum DOC for ATP & ACP	Feed IPR
Cast Iron	160 HB	75-200	200-550	0.020	0.060	.0005-.010
Carbon Steel	18 Rc	75-200	200-450	0.018	0.060	.0005-0.010
Alloy Steel	20 Rc	75-200	200-425	0.015	0.060	.0005-0.010
Tool Steel	25 Rc	75-175	175-300	0.010	0.030	.0005-0.010
300 Stainless Steel	150 HB	75-175	175-350	0.015	0.028	.0005-0.010
400 Stainless Steel	195 HB	75-210	130-420	0.012	0.028	.0005-0.010
High Temperature Alloy (Ni & Co Base)	20 Rc	50-130	130-300	0.008	0.020	.0005-0.010
Titanium	25 Rc	50-120	120-275	0.009	0.022	.0005-0.010
Heat Treated Alloys (38-45 Rc)	40 Rc	50-100	100-200	0.005	0.010	.0005-0.010
Aluminum	100 HB	75-250	250-750	0.025	0.095	.0005-0.010
Brass, Zinc	80 HB	75-300	250-650	0.023	0.090	.0005-0.010

SFM = Surface Feet per Minute

These are starting parameters only. Length to Diameter ratios, setup, and machine rigidity may affect performance. This chart reflects the maximum Depth of Cut (DOC) acceptable at the minimum Inches per Revolution (IPR).

Which Indexable Boring Bar Should I Choose?

Verify Hole Diameter
Start by checking the diameter of the hole to be machined using the part or print. Choose a boring bar with a minimum bore diameter smaller than the required machining diameter.
Check Machine Compatibility
Determine the correct shank size for your machine. If a larger shank is needed, consider using a step bar.
Select the Appropriate Lead Angle
- Use a 0° lead for boring to a shoulder.
- Use a 5° lead for boring and facing a shoulder.
Choose the Right Insert
Select between a flat top or chip control insert based on the application and material being machined.
Determine the Corner Radius
Choose from .003”, .007”, or .015” radius options based on the desired finish and part specifications.

Which Insert Grade Should I Choose?

Type	Description
Uncoated	Submicron premium carbide grade for machining steel and non-ferrous materials.
AlTiN+	Premium coated grade for steel, cast irons, and high-temperature alloys at highest SFM
CBN	Ideal for hardened steeeel (45+ Rc) and cast iron
PCD	Ideal for non-ferrous materials

Shop Indexable Boring Bars

Contact the Engineering Department

Troubleshooting

Problem	Cause	Solution
Rapid Flank Wear	Cutting Conditions	Reduce the cutting speed.
	Insert	Select a coated grade.
	Heat	Use the SCT coolant holder. If coolant is not available, use shop air and a coated tool. Use a coolant through boring bar.
Built-Up Edge	Insert	Select a coated grade.
	Cutting Force	Use chip control insert to free up cut.
	Heat	Use coolant through boring bar or holder. If coolant is not available, use shop air and a coated tool. Use a coolant through boring bar.
Insert Breakage	Cutting Conditions	Reduce Depth of Cut. Reduce feed rate.
	Insert	Select a larger corner radius.
	Part	Check the drilled hole to make sure the full diameter of the drill is deeper than the programmed bore depth.
Surface too Rough	Cutting Conditions	Reduce feed rate. The rate is too great for the nose radius.
	Insert	Select a larger corner radius. The feed rate (IPR) should not be greater than 1/2 the nose radius.
Chatter	Setup	Set insert above center. Change the speed of the machine. The overhang ratio should be less than eight times the bar diameter for carbide. Clamping length should be at least three times the boring bar diameter.
	Boring Bar	Select the largest diameter bar that will bore the required diameter.
Taper Bigger in Back	Cutting Forces	Forces may deflect bar below center causing the hole to become larger.
	Built-Up Edge	A built-up edge will cause the hole to become large until the built-up edge breaks off, then the hole will be smaller.
	Program	If the taper is consistent (not from chip packing), then the program can be altered to bore a taper in the opposite direction, resulting in a straight hole.
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 insert and cause the bar to deflect away from the bore.
	Program	If the taper is consistent (not from chip packing), then the program can be altered to bore a taper in the opposite direction, resulting in a straight hole.