Indexable Drills — Catalog and Selection

Compiled 2026-04-04 · 40 chunks, 12 posts · drilling · indexable-inserts · tool-selection · speeds-feeds · carbide

Summary

Indexable drills revolutionize hole-making by combining replaceable carbide inserts with rigid tool bodies to deliver superior productivity, hole quality, and tool life compared to traditional twist drills. These drills typically range from 15-160mm (0.590"-6.299") diameter and excel at high-volume production drilling, particularly in challenging materials where consistent performance and predictable tool costs matter most.

Major Manufacturers and Product Lines

Kennametal

  • KUB Quatron series: General purpose drilling with excellent chip evacuation
  • Diameter range: 12-160mm
  • Insert grades: KC7315 (steel), KC7325 (stainless), KC7340 (cast iron)

Iscar

  • Chamdrill series: Most popular line for general applications
  • Sumitomo drills: Known for straight hole drilling capabilities
  • Part numbers follow format: MM ECS-[A/B][diameter]X[length]-2T[shank]
  • Example: MM ECS-A5.00X12-2T08 (5mm diameter, 12mm cutting length)

Guhring

  • 4111 series: Pilot inserts (145° point angle)
  • 4115 series: Main/finishing inserts (140° point angle)
  • Excellent for hardened materials up to 48 HRC

Sandvik Coromant

  • CoroDrill series: Wide range with modular system
  • DE10 designation for standard indexable drills
  • Strong coolant delivery systems

Speeds and Feeds by Material

Carbon Steel ([[1018-1045-steel]], [[4140-steel]])

Manufacturer recommendations:

  • Surface speed: 400-600 SFM
  • Feed: 0.003-0.008 IPR
  • Example: 1.25" drill at 550 SFM = 168 RPM

Shop floor reality:

  • Many machinists run 350-450 SFM for better insert life
  • Feed rates of 0.005-0.006 IPR work well in practice
  • One machinist reports: "550 SFM, 0.006 IPR in DME #1 steel normally runs 40-50% spindle load"

Stainless Steel ([[304-stainless]], [[17-4ph-stainless]])

  • Surface speed: 250-400 SFM
  • Feed: 0.004-0.010 IPR
  • Higher feeds help prevent work hardening

Hardened Steel (40-48 HRC)

  • Surface speed: 80-150 SFM
  • Feed: 0.003-0.005 IPR
  • Example: 20.64mm drill in 4340 at 43 HRC: 80 SFM, 0.005 IPR (376 RPM)

[[Aluminum-6061]], [[7075-aluminum]]

  • Surface speed: 800-1500 SFM
  • Feed: 0.006-0.015 IPR
  • Example: 1⅜" drill at 1400 RPM, 0.003 IPR (500 SFM equivalent)

[[Cast-iron]]

  • Surface speed: 300-500 SFM
  • Feed: 0.005-0.012 IPR
  • Dry cutting often preferred

Insert Selection and Grades

Common Insert Geometries

  • Pilot inserts: 145° point angle for hole starting
  • Main inserts: 140° point angle for finishing
  • Corner radius: 0.8-1.2mm typical

Grade Selection by Material

  • Uncoated carbide: General purpose, good for aluminum
  • TiAlN coated: Steel applications, extended tool life
  • KC7315: Kennametal general steel grade
  • KC7325: For stainless and difficult materials
  • ACP5FL: Iscar grade for standard steel drilling

Operational Guidelines

Drilling Parameters

  • Pilot hole depth: Typically 3x diameter for initial engagement
  • Pecking cycles: Start 3x diameter, reduce by 1x diameter each cycle to minimum 1x diameter
  • Chip observation: Look for "6's and 9's" - small broken chips indicate proper parameters

Entry Techniques

Experienced machinists recommend:

  • Pilot drill to depth of inserts before full engagement
  • Enter at 25% feed rate, ramp to 100% once fully engaged
  • Monitor spindle load - should remain consistent throughout depth

Coolant Requirements

  • Through-spindle coolant strongly recommended for depths >3x diameter
  • Flood coolant acceptable for shallow holes
  • Proper concentration critical for insert life

Common Problems and Solutions

Insert Chipping

Symptoms: Premature insert failure, poor surface finish Causes:

  • RPM too low (common with hardened materials)
  • Interrupted cuts without proper entry technique
  • Insufficient coolant flow

Solutions:

  • Increase surface speed within material limits
  • Use progressive entry technique
  • Verify coolant concentration and pressure

Hole Walking/Poor Straightness

Symptoms: Holes not perpendicular, reamer won't clean up Causes:

  • Inadequate machine rigidity
  • Worn spindle bearings
  • Improper workholding

Solutions:

  • Use pilot drill for initial guidance
  • Consider double-margin drills for better guidance
  • Upgrade to Guhring or similar precision brands

Long Stringy Chips

Symptoms: Blue chips, poor surface finish, high spindle load Causes:

  • Feed rate too low
  • Dull inserts
  • Poor material batch

Solutions:

  • Increase feed rate to 0.006-0.008 IPR
  • Replace inserts
  • Verify material specifications

Shop Floor Tips

Depth Control

"Use the quill stop method: Set quill stop deep enough for full penetration plus clearance. Lock quill, move knee to touch drill point. Retract quill, zero knee, move up required depth. Drill until quill stop hits - perfect depth every time."

Insert Life Monitoring

  • Track cutting time: Expect 160-190 minutes in hardened steel applications
  • Monitor spindle load consistency
  • Set load monitoring 5-10% above normal operating load

Chip Management

  • For holes >1.5" diameter: Expect aggressive chip ejection
  • Use chip guards and proper PPE
  • "It's hard to beat the satisfaction of hogging out 3" diameter in 4 seconds"

Pre-drilling Strategy

  • Drill to 97% of final diameter for finish operations
  • Leave 0.015" per side for [[boring]] or [[reaming]] cleanup
  • Consider [[carbide-drills]] for pilot holes in challenging materials

Size Selection Chart

Diameter Range Application Typical Inserts
12-20mm Precision holes, hardened materials 2 inserts (pilot + main)
20-40mm General production drilling 2-3 inserts
40-80mm Heavy drilling, large production 3-4 inserts
80-160mm Specialized applications 4+ inserts
  • [[drilling]] — fundamental drilling operations and techniques
  • [[carbide-drills]] — solid carbide alternatives for smaller holes
  • [[boring]] — finishing operations after indexable drilling
  • [[reaming]] — precision sizing after drilling operations
  • [[insert-selection-guide]] — detailed insert grade selection criteria
  • [[tool-wear-diagnosis]] — identifying and preventing premature tool failure
  • [[chip-control]] — managing chip formation and evacuation