Support > Safety > Deep Hole Drilling Guidelines > Structural Steel T-A®

Deep Hole Drilling Guidelines

 

For use with drills greater than 9xD (extended, long, XL, 3XL, and special length)
 
Step 1: Pilot Hole
  • 100% RPM
  • 100% IPR (mm/rev)
Details:
  • Establish the pilot hole using the same diameter short drill to a depth of 2xD minimum.
  • Utilize a pilot drill with the same or larger included point angle.
Coolant: ON
Step 2: Feed-In
  •  50 RPM max
  •  12 IPM (300 mm/min)
Details:
  • Feed the longer drill within 1/16" (1.5mm) short of the established pilot hole bottom at a maximum of 50 RPM and 12 IPM (300 mm/min) feed rate.
Coolant: OFF
Step 3: Deep Hole Transition Drilling
  • 50% RPM
  • 75% IPR (mm/rev)
Details:
  • Drill additional 1xD past the bottom of the pilot hole at 50% reduction of recommended speed and 25% reduction of recommended feed.
  • Minimum of 1 second dwell is required to meet full speed before feeding.
Coolant: ON
Step 4: Deep Hole Drilling - Blind
  • 100% RPM
  • 100% IPR (mm/rev)
Details:
  • Drill to full depth at recommended speed and feed for longer drill according to Allied speed and feed charts.
  • No peck cycle recommended.
Coolant: ON
Step 5: Deep Hole Drilling at Breakout
  • 50% RPM
  • 75% IPR (mm/rev)
Details:
For through holes only:
  • Reduce speed by 50% and feed by 25% prior to breakout.
  • Do not break out more than 1/8" (3mm) past the full diameter of the drill.
Coolant: ON
Step 6: Drill Retract
  • 50 RPM max
Details:
  • Reduce speed to a maximum of 50 RPM before retracting from the hole.
Coolant: OFF
Tool failure can cause serious injury. To Prevent:
  - When using holders without support bushing, use a short T-A® holder to establish an initial hole that is a minimum of 2 diameters deep.
  - Do not rotate tool holders more than 50 RPM unless it is engaged with the workpiece or fixture.
Factory technical assistance is available for your applications through our Application Engineering Team.
This triangle is a safety hazard symbol. It alerts you to potential safety hazards that can cause tool failure and serious injury. When you see this symbol in the catalog, look for a related safety message that may be near this triangle or referred to in the nearby text.