Router Bit Profiles Guide

1/2 inch shank router bits are stronger, more stable, and produce less vibration than 1/4 inch shanks. They can handle heavier cuts and last longer because the larger shank flexes less under load. Use 1/2 inch shanks whenever your router accepts them. 1/4 inch shanks are suitable for lighter trim work and smaller routers, but are more prone to breaking under stress or when making aggressive cuts.

Carbide-tipped router bits stay sharper 10-25 times longer than HSS (High Speed Steel) bits and can handle harder materials including plywood, MDF, and hardwoods without dulling quickly. While more expensive upfront, carbide bits are more economical long-term because they need replacing far less often. HSS bits are only recommended for softwoods and very occasional use where the lower cost outweighs the shorter lifespan.

Larger bits require slower speeds to prevent burning and maintain safety. For bits up to 1 inch diameter, use 22,000-24,000 RPM (full speed on most routers). For 1-2 inch bits, use 18,000-22,000 RPM. For 2-2.5 inch bits, use 12,000-16,000 RPM and work on a router table. For bits over 2.5 inches, use 8,000-12,000 RPM with a heavy-duty router table setup. Always start slower and increase speed only if needed for a cleaner cut.

Bearing-guided bits have a ball bearing that follows a template or the workpiece edge, making them self-guiding without needing a fence. They're ideal for edge profiles and template work. Non-bearing bits (also called pilotless) require a fence, edge guide, or guide bushing for control. They're used for grooves, dadoes, and router table work where the fence provides consistent guidance. Some bits come with interchangeable bearings to adjust the cut depth.

Start with these essential bits that cover most common tasks: 1/4 inch and 1/2 inch straight bits for dadoes, grooves, and rabbets; a 1/4 inch roundover for softening edges on furniture and projects; a 45-degree chamfer for decorative beveled edges; a flush trim bit for template work and edge banding; and a rabbeting bit with bearing set for back panels and joinery. A quality starter set from Freud, Whiteside, or Yonico will include most of these and save money over buying individually.

Router bit burning is caused by friction from several factors. Use sharp carbide bits (dull bits generate more heat), reduce RPM for larger diameter bits, and maintain a steady feed rate that's not too slow (pausing or moving slowly causes burn marks). Take multiple shallow passes instead of one deep cut, especially on hardwoods. Avoid stopping the router mid-cut as this leaves burn marks. Clean pitch and resin buildup from bits regularly using a dedicated bit cleaner or simple green solution.

The main router bit types are straight bits (grooves and dados), edge forming bits (roundover, chamfer, cove, ogee and bead), joinery bits (dovetail, rabbeting, tongue and groove, rail and stile), and specialty bits (flush trim, pattern, spiral and V-groove). Edge forming bits shape the profile on the outside of a board, and joinery bits cut the joint.

A roundover bit rounds over an edge. It is sold by radius, such as 1/8, 1/4, 3/8 and 1/2 inch, and a bearing on the tip rides the edge to set the depth. A 1/4 inch roundover is the most common size for tabletops and shelves.

The straight bit is the most common router bit. It cuts grooves, dados, rabbets and mortises, and it comes in diameters from 1/8 to 1 inch. Next most used are the roundover, chamfer and flush trim bits.

The first number is usually the cutting diameter (or profile radius) and the second is the shank diameter. Check both, because a 1/2 inch cutting diameter bit may come with either a 1/4 inch or a 1/2 inch shank, and the collet on your router has to match the shank.