How to read a profile
Each silhouette shows the bit standing upright: the plain shank at the top goes into the collet, the cutting profile is below it, and a white disc is a bearing. A bearing at the tip follows the edge or template beneath the cutter; a bearing above the cutter follows a template on top of the work. On the spiral bits, the red arrows show which way each lifts the chips: an up-spiral up and out of the cut, a down-spiral down into it, and a compression bit both ways toward the middle, which is why Freud describes it for faces that must stay clean on both sides.
Which bit for which job
| Job | Bits that do it | What guides the cut |
|---|---|---|
| Groove or dado across a board | Straight; down-spiral where the top face must stay clean | Clamped straightedge, edge guide or table fence |
| Mortise or deep blind hole | Straight; up-spiral to clear chips (Freud) | Edge guide or jig on a plunge router |
| Rabbet on an edge | Rabbeting bit with its bearing; straight bit with a fence | Bearing, or fence on a table |
| Flush trim or template copy | Flush trim (template below); pattern bit (template on top) | Bearing the same diameter as the cutter |
| Rounded, bevelled or moulded edge | Roundover, chamfer, Roman ogee | Bearing, or fence on a table |
| Dovetail or sliding dovetail | Dovetail bit | Jig with a template guide, or table fence |
| Slot for a spline or tongue | Slot cutter | Bearing on its arbor |
No bit type is better in general; the job, the guide and the router's limits decide. Joints themselves are covered in the joinery pages.
For the joints in that table, see dovetails, mortise and tenon and box joints; for steering a bit along a guide or template, jigs and templates.
What a listing tells you
- Cutting diameter. Sets the opening the bit needs and, with the maker's rating, how fast it may turn.
- Shank. Must equal the collet fitted: 1/4 in, 8 mm and 1/2 in are not interchangeable. Bosch's Colt manual warns a smaller shank can come loose and become a projectile.
- Cutting length and bearing size. How deep one setup reaches, and where a guided cut lands.
- Maximum rpm. The maker's limit for that bit. Freud's examples here run from 16,000 to 24,000 rpm; the speed chart sets ratings against router dials.
- Materials. Freud lists the materials each bit is for — its chamfer bit, for example, hardwood, softwood, plywood and composites. Check the list before routing sheet goods.
Dimensions are explained with a drawing, and the makers' rules for seating a bit compared, in router bits. Many bits sold for CNC machines appear in the same catalogues; Freud treats CNC feeds and speeds separately and says there is no hard-and-fast rule for them, and this chart does not cover them.
Before choosing a bit from the chart
- The cut you need, and what will guide it
- A shank that matches your router's collet
- A cutting diameter within your router's openings
- The bit's maximum rpm, and a router setting at or below it
- The maker's list of materials for the bit
The router family is mapped in the router guide; table-mounted profiling is set up in router tables.
Sources
Every example is one Freud bit with the figures on its product page; other sizes of the same type have other figures. Uses are as Freud describes them. Silhouettes are drawn for this chart and are not to scale.
- 1.
04-110 Double Flute Straight bit. Freud.
Used for: Straight bit: 1/2 in diameter, 1-1/2 in cutting length, 1/2 in shank, 24,000 rpm.
- 2.
75-104 Up Spiral bit. Freud.
Used for: Up-spiral: 1/2 in, three flutes, 24,000 rpm; chip removal, through-cuts, mortises and blind holes; best cut quality on the bottom surface.
- 3.
76-102 Down Spiral bit. Freud.
Used for: Down-spiral: 5/16 in, 1/2 in shank, 24,000 rpm; grooves and dadoes in single-sided veneer and laminate, top-surface finish.
- 4.
77-104 Compression bit. Freud.
Used for: Compression: 3/8 in, 11/32 in up-cut length, 1/2 in shank, 24,000 rpm; clean faces in double-sided veneer and laminate.
- 5.
42-100 Bearing Flush Trim bit. Freud.
Used for: Bearing flush trim: 1/2 in cutter and bearing, 1/2 in shank, 24,000 rpm; laminate trimming and pattern routing.
- 6.
50-101 Top Bearing Flush Trim bit. Freud.
Used for: Top-bearing flush trim: 1 in cutter and bearing, 1/2 in shank, 24,000 rpm; template work.
- 7.
32-524 Rabbeting bit set with bearings. Freud.
Used for: Rabbeting set: 1-3/8 in, bearings for depths from flush to 1/2 in, 1/2 in shank, 16,000 rpm.
- 8.
34-128 Rounding Over bit. Freud.
Used for: Roundover: 1/8 in radius, 3/4 in diameter, 1/2 in bearing, 1/4 in shank, 24,000 rpm.
- 9.
40-102 Chamfer bit. Freud.
Used for: Chamfer: 15°, 1 in diameter, 1/2 in shank, 24,000 rpm; hardwood, softwood, plywood and composites.
- 10.
38-314 Roman Ogee bit. Freud.
Used for: Roman ogee: 1-1/16 in, 1/4 in shank, 18,000 rpm.
- 11.
22-102 Dovetail bit. Freud.
Used for: Dovetail: 8°, 13/16 in, 1/2 in shank, 24,000 rpm; suits popular dovetail jigs.
- 12.
63-162 Slotting Cutter set. Freud.
Used for: Slotting cutter: 2 in diameter, 9/16 in depth of cut, 1/4 in shank, 16,000 rpm; splines and tongue-and-groove.
- 13.
GKF125CE Colt Palm Router Operating/Safety Instructions. Bosch, 2018.
Used for: A shank smaller than the collet able to come loose and become a projectile.
- 14.
Router Bit Feed and Speed for CNC. Freud, 2017.
Used for: CNC feeds and speeds treated separately, with no hard-and-fast rule.
About this chart
Written by BenchRoot Editorial. How BenchRoot sources, checks and corrects its pages is set out in the Editorial Policy. If something here is wrong or unclear, the contact page explains how to tell us.