A rotary burr (also called a rotary file) is a cutting tool whose 1/4" shank is chucked into a die grinder or rotary drill to remove material, deburr edges, and shape surfaces. Burrs are identified by trade number: SA is the cylindrical shape with a flat end, the 3 corresponds to a 3/8" head diameter, and the X marks the long version. The SA-3X has the same 3/8" head as the SA-3 but a 1-1/2" length of cut and a 3-1/4" overall length, compared with 3/4" and 2-1/2" on the standard SA-3.
Machinists, fabricators, and maintenance technicians use cylindrical burrs for deburring, contouring, shaping, chamfering, and weld removal on steel, cast iron, and stainless steel. Double cut means the flutes are ground in both left- and right-hand directions, which gives better operator control, rapid stock removal, and a smoother finish in harder materials. Softer non-ferrous metals such as aluminum generally call for a different cut pattern, and SGS lists a separate SA-3NF variant in the same shape and size range for that purpose.
Common configuration for the SA-3X: carbide, double cut, 3/8" head diameter, 1-1/2" length of cut, 1/4" shank, and 3-1/4" overall length, listed by SGS Pro (part numbers 10128 and 10125) and by Monster and others. AA Abrasives lists a USA-made SA-3X (part 36078) with an overall length of 2-1/8", which does not match the 3-1/4" in the standard tables, so confirm dimensions with your supplier. Recommended speeds vary by maker: Forney's SA-3 lists 4,000 to 45,000 RPM on steel, while Platinum lists a 66,000 RPM maximum for its SA-3, so follow the specific manufacturer's guidance for the burr you buy.
Quick-Reference Spec Glossary
- Trade number
- SA-3X
- Shape
- SA cylindrical, flat end
- Cut
- Double cut (flutes ground in both directions)
- Head diameter
- 3/8"
- Length of cut
- 1-1/2" (SA-3 is 3/4")
- Shank diameter
- 1/4"
- Overall length
- 3-1/4" on standard tables (one listing says 2-1/8")
- Material / use
- Carbide, for die grinders and rotary drills; steel, cast iron, stainless steel