Tool Selection Guide

Use the questions below to determine your tooling requirements.  You can also fill out and fax this information to us if you need assistance with your tooling selection.  Fax it to: (877) 776-9994.






  1. What is the diameter tolerance? _______________________________ (determines rough or finish head)

  2. What is the finish diameter of the bore? _________________________ (determines connection diameter)

  3. Is the bore a thru bore, or step bore design? _____________________ (75 lead = thru bore / 90 lead = step bore)

  4. What is the material to be machined? __________________________ (determines insert code selection)

  5. What is the machine spindle? ________________________________ (determines toolholder selection)

  6. What is the finish depth of the bore? ___________________________ (determines length of shank & extensions)                                          

  7. What end of the spindle projection do you require?______________ (determines length of shank & extensions)

  8. Does the spindle have thru spindle coolant? _____________________   Flood coolant? ____________ DIN "B"?_____________________   
    (if yes, calculate length of shank requirements)

  9. What is the starting diameter of the bore? _______________________

  10. What is the depth of cut requirement? __________________________   Finish diameter - starting diameter / 2 = depth of cut_______________ (determines insert tool nose radius selection)

Misc: Select coolant through spindle based on connection diameter and bore depth requirements (question #7 above)

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Need help? Call (800) 579-3921 for fast, friendly assistance.

  Boring Tips

Speeds & Feeds
For best finish, generally feed at 25% of nose radius.  Optimal speeds & feeds depend upon material, machine, tool overhang and setup conditions.

Insert Corner Radius
For heavy roughing use the largest available corner radius unless otherwise specified.  For finish boring use the smallest corner radius to minimize lateral deflection, especially on long overhangs.

Boring Depth
Depths of 5x diameter for rough boring and 3x diameter for finish boring using carbide tooling are achievable.  At depths greater than that harmonic chatter and deflection may become a problem, causing you to adjust feeds & speeds.  Changes in the amount of side block extension may require adjustment of feeds & speeds. 

Depth of Cut
Depth of cut is a function of material and tool nose radius.  Generally the ideal minimum diameter depth of cut is equal to the insert nose radius.  The maximum stock removal rate for rough boring may have to be decreased on very tough materials or extended overhangs and extended slide blocks.

Rough Boring 75 vs 90
For maximum removal rates when a square shoulder is not required, use a 75 boring head.  The 75 head self-centers in the hole for a more stable cut.  However, if the hole is off-center or off-angle then use the 90 head because it will have less tendency to follow the existing hole.

Boring Bar Overhang
The maximum boring depth for steel boring bars is 5x bar diameter.  For solid carbide bars 7x bar diameter.  To maximize boring efficiency we recommend the shortest possible overhang be used.

Key to ordering boring heads by part number

 A 22 75 400

 A = finish heads, D = rough heads (see question #1 above)
 22 = connection diameter (see question #2 above)
 75 = approach angle (see question #3 above)
 400 = insert style of CT cartridge (see question #4 above)
Key to ordering toolholders by part number

 CT 330 22 100

 CT = type of shank (see question #5 above)
 330 = taper size (see question #5 above)
 22 = connection diameter (match head connection)
 100 = boring depth (BD) (see question #6 above)