While cutting seats, use a steady, slow to medium speed.
Flex-shafts can operate at speeds up to 14,000 rpm. Burs and drills
should not approach this speed while cutting metal. You should
operate the flex-shaft at no more than medium speed, and The Larger
The Bur The Slower The Speed. High Speed Steel burs are a
description of the type of steel used and not indicative of the
speed used to operate.
Brad Simon CMBJ