Two numbers, set by two makers
A bit's maximum speed is its maker's limit for that bit, printed on its listing and, Amana says, etched on its shank. A router's speed is what its dial or motor delivers. Setting the speed means bringing the second number at or under the first. Larger bits need lower limits because their cutting edges move faster at the same rpm; every maker's figures here fall as diameter rises.
Where the makers' figures differ
| Freud bit | Diameter | Freud's maximum | Amana's ceiling for that diameter |
|---|---|---|---|
| 38-314 Roman ogee | 1-1/16 in | 18,000 rpm | 28,000 rpm (under 2 in) |
| 32-524 rabbeting set | 1-3/8 in | 16,000 rpm | 28,000 rpm (under 2 in) |
| 63-162 slotting cutter | 2 in | 16,000 rpm | 22,000 rpm (2 to 2-3/8 in) |
Amana's ceilings are for its own symmetrical bits; Freud's figures are for the single bits named. Neither applies to the other maker's bits. Use the rating of the bit in your collet.
The differences are large: Freud rates its 1-3/8 in rabbeting set at 16,000 rpm, while Amana's table allows its own bits under 2 in up to 28,000. A diameter table is no substitute for the rating of the bit you are holding.
The rules in the manuals
| Source | Rule |
|---|---|
| Bosch, 1617 manual | The accessory's rated speed must be at least the highest speed marked on the tool |
| Bosch, Colt manual | Never operate a bit above its maximum rated speed; the bit maker may also recommend a speed |
| DEWALT, DCW600 manual | Follow the bit maker's speed recommendations; ask the bit maker if unsure |
| Freud, rail-and-stile instructions | Set the router to the cutter's recommended speed; never exceed the bit's maximum rpm |
| Freud, CNC feeds and speeds | For CNC machines, a bit rated at least to the machine's highest speed |
| Amana | Never exceed the maximum shown; check the rating etched on the shank |
The rules disagree: Bosch's 1617 manual and Freud's CNC guidance want a bit rated for the machine's top speed; Bosch's Colt manual, DEWALT and Freud's router instructions set the limit at the bit's own rating. Follow the stricter rule your own manual gives.
Setting the dial
Setting the speed for a bit
Find the bit's rating
On its listing or packaging, or etched on the shank. If you cannot find it, DEWALT's advice is to contact the bit maker.
Check your router's rule
If its manual asks for bits rated to its highest speed, as Bosch's 1617 manual does, use only such bits in it.
Set at or below the rating
Use the router's own table — the chart above has three. Bosch, DEWALT and Milwaukee all put larger bits at lower settings.
Refine on scrap
Bosch says the exact setting comes from experience and preference within those limits. Burning and chatter are as often feed problems as speed problems — see using a router.
Speed, feed rate and depth of cut are separate settings. A lower speed does not make a deeper pass safe, and there is no universal depth per pass. The Bosch, DEWALT and Milwaukee routers cited here hold the set speed under load electronically, their manuals say; that holds the speed, it does not correct a feed that is too fast.
Before setting router speed
- The rating of the bit in the collet, not of its type
- Your router's rule on bit ratings
- The router's own dial table
- A setting at or below the bit's rating
- A test cut on scrap
Profiles and the bits named here are drawn in the bit profile chart; seating and sizing a bit is in router bits; the family is mapped in the router guide. CNC feeds and speeds are outside this chart.
Sources
Every rating is the named maker's for its own bits, and every dial table the router maker's for its own router. Amana's diameter table applies to Amana's symmetrical bits only. Nothing here is a speed for any bit not named.
- 1.
Max RPM Guide for Amana Tool Router Bits. Amana Tool.
Used for: Maximum rpm by cutting diameter for Amana's symmetrical bits — 28,000 under 2 in (50 mm) down to 13,000 over 3-5/8 in (90–100 mm) — and the instruction to check the rating laser-etched on the shank.
- 2.
32-524 Rabbeting bit set with bearings. Freud.
Used for: A 1-3/8 in rabbeting set rated at 16,000 rpm.
- 3.
38-314 Roman Ogee bit. Freud.
Used for: A 1-1/16 in Roman ogee rated at 18,000 rpm.
- 4.
63-162 Slotting Cutter set. Freud.
Used for: A 2 in slotting cutter set rated at 16,000 rpm.
- 5.
Premier Adjustable Rail and Stile System (instructions poster). Freud.
Used for: Setting the router to the cutter's recommended speed and never exceeding its maximum rpm; bits over 1-1/2 in only in a table.
- 6.
Router Bit Feed and Speed for CNC. Freud, 2017.
Used for: For CNC use, a bit's rated speed at least the machine's highest speed, and no hard-and-fast rule for feeds and speeds.
- 7.
1617, 1617EVS, 1617EVSPK, 1618EVS Operating/Safety Instructions. Bosch, 2018.
Used for: Dial settings of the 1617EVS from 8,000 to 25,000 rpm with low settings for larger bits; an accessory's rated speed at least the highest speed marked on the tool; electronics holding the set speed under load.
- 8.
GKF125CE Colt Palm Router Operating/Safety Instructions. Bosch, 2018.
Used for: Dial settings of the Colt from 16,000 to 35,000 rpm; exact settings by experience and preference, with the bit maker's recommendation; never running a bit above its maximum rated speed.
- 9.
DCW600 20V Max* Compact Router, Instruction Manual. DEWALT, 2022.
Used for: Seven approximate dial settings from 16,000 to 25,500 rpm; following the bit maker's speed recommendations, and contacting the bit maker if unsure; several light passes.
- 10.
M18 FUEL Compact Router, Cat. No. 2723-20, Operator's Manual. Milwaukee Tool.
Used for: A 10,000–31,000 rpm dial with higher speeds for smaller bits and lower for larger ones; feedback control holding speed between no load and load.
About this chart
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