Opening Drill
Aerospace Gears: Opening Drill® 
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The Challenge

The customer manufactures aerospace gears made from 4340 (28 Rc) using a Mazak Lathe with oil-based water soluble coolant.

The customer realized this process was not optimal, and they contacted Allied for a solution.

The Opening Drill® paid for itself after only 60 parts. The customer also makes a number of aerospace gears from of 15-5 stainless and 4340 (ranging from 1.00” ID to 4.50” ID (25.4 mm to 114.3 mm)), and they plan to utilize the Opening Drill in these additional applications.


Product: Opening Drill
Objective: Improve Process
Industry: Aerospace
Part: Gears
Material: 4340
Hole Ø: 3.75" (95.25mm)
Hole Depth: 7.00" (177.8mm)

The Solution
The Opening Drill
  • Drill Holder: OP3-1L-SS1.5


Competitor Boring Bar

Opening Drill®




Feed Rate

0.012 IPR (0.305 mm/rev)

0.004 IPR (0.102 mm/rev)

Penetration Rate

4.8 IPM (121.92 mm/min)

2.037 IPM (51.74 mm/min)

Cycle Time

19 min

3 min 30 sec

Tool Life

30 parts

30 parts

The Advantages
The Opening Drill provided:
  • 82% cycle time decrease
  • Reduced boring passes
  • Decreased cost per hole