Definition - What does Fly Cutter mean?
Fly cutter is a single point cutting tool which is similar to a lathe tool mounted in a special holder. Fly cutters are basically rotary tools that use one or more single point tools for plane surfacing. There are many types of fly cutters with the most basic examples being the Point Cutter, Rotary Carving Tool and Rotary Cutting Tool.
Petropedia explains Fly Cutter
Fly cutters function in several ways. A normal fly cutter can be adjusted to cut up to a 2 inch (51 mm) diameter and is easily capable of taking a 0.01 inch (0.25 mm) deep cut in aluminum at this diameter. The ¾ inch body fly cutter uses a 3/16 inch tool bit. A 1-1/8 inch body fly cutter uses a ¼ inch tool bit. The 1-3/8 inch body fly cutter uses a 5/16 inch tool bit. Most fly cutters are available with a holder, draw bolt, thrust washer, and a left-hand carbide cutting tool. A point cutter is available in long (500 mm) and short (300 mm) sizes. A point cutter has two cutting edges per blade. The blade is similar to 1/3 of a rotary blade. It slips in and out of the handle for safe storage. A rotary tool accessory is an ideal instrument for cutting, carving, sanding, drilling, and grinding. A rotary tool accessory consists of a variable speed motor for smooth operation with speeds of up to 30,000 rpm. The main body of a rotary tool accessory has a spindle lock to allow opening and closing the 1/8 inch collet so as to fit standard rotational tools. Fly cutters can be designed and manufactured to meet most industry specifications.
Fly cutters are used primarily on a milling machine for machining large, flat surface areas. Fly cutters can be used in machining centers and manual mills without the use of additional arbors. Fly cutters are also used to remove large amounts of metal and level it with the advantage that it can be re-sharpened by straightforward grinding.