Long Forstner Hinge Boring Drill Bits 16mm - 25mm

• High hardness, rustproof, solid and durable.
• Self-centering point, do not need assistant center drilling or center punching.
• Drilling and tapping in one, one-step processing, greatly save processing steps and time costs, improve working efficiency.
• Spiral groove, within the processing thread, cutting up to exclude, and was curled applied internally threaded through holes.
• Wear and long life.

Specification:

• Materials: high quality alloy
• Size: 16mm, 18mm, 20mm, 22mm and 25mm
• Shank: 6.35mm(1/4") hex shank
• Total Length: Approx. 130mm
• Recommended speed: <1000RPM
• Tips: Don't suggest to use 12V electric drill.
• There are 2~3% difference according to manual measurement, please understand.