Machinist School - Speeds for Woods

How fast you go matters .... Maybe you have seen your drill smoking its way through a board.

According to this chart, softwoods are drilled two or three times faster than hardwoods. Here's the test:

A pine board (softwood) is being drilled with a 2" diameter bit at 500 RPM. What is the cutting speed in feet per minute? (answer = about 250 feet per minute)

A piece of dry oak (hardwood) is being drilled with a 2" diameter bit at 250 RPM. What is the cutting speed in feet per minute? (answer = about 125 feet per minute)

Drill bits for cutting wood are typically made of "top quality high carbon tool steel". There are lots of top quality high carbon tool steels such as 1095(high carbon steel without alloys), O1 (Oil Hardening high carbon steel), and W1 (Water Hardening high carbon steel).

A rule of thumb used at the Machinist School is that Aluminum cuts about like dry oak knots. A cutting speed of 180 feet per minute works well for cutting 6061 T6 aluminum using a high speed steel tool bit without cutting fluid. (6061 T6 is "gummy" above 180 feet per minute until you reach a speed of about 600 feet per minute. At 600 feet per minute, it starts cutting good again.)

For cutting hardwood with high speed steel bits, Machinist School suggests 180 feet per minute as a starting point. For cutting softwoods with high speed steel bits, Machinist School suggests 300 feet per minute as a starting point. (Many softwoods cut very nicely a speeds greatly in excess of 300 feet per minute.)

Happy Drilling!!!