Some Handy Router Information

Just as the materials they cut are different, so are the power tools.  As wood was once a living, organic material, wood density, timber hardness and moisture will all combine to make each piece of wood unique.  Thus, the information below can only be used as guidelines...

Router Speed Settings (Guidelines for speed settings based on materials and bit sizes)

Key:    
P - Poor (marginal)     G - good     E - excellent     ø - not recommended     *** - DO NOT EXCEED for safe routing

Material (DeWalt 618 series routers)	Cutter Diameter (Inches)	Cutter Diameter (Millimeters)	8,000 RPM Setting 1	12,000 RPM Setting 2	14,000 RPM Setting 3	16,000 RPM	18,000 RPM Setting 4	21,000 RPM Setting 5	24,000 RPM Setting 6
MAXIMUM SAFE SPEEDS ***	≤ 1" 1" - 1¼" 1¼" - 2¼" 2¼" - 3½"	≤ 25.4 mm 25.4 - 31.75 31.75 - 57.15 57.15 - 88.9	- - - -	- - - ***	- - - -	- - *** -	- *** - -	- - - -	*** - - -
Hardwoods e.g., oak, maple, walnut	≤ 1/2" 1/2" - 1 1/8" ≥ 1 1/8"	≤12.7 12.7 - 28.575 ≥28.575	ø ø G	ø ø E	P P P	G G ø	G E ø	E G ø	G ø ø
Softwoods e.g., pine, cedar	≤ 1/2" 1/2" - 1 1/8" ≥ 1 1/8"	≤12.7 12.7 - 28.575 ≥28.575	ø ø G	ø P E	P G P	P G ø	G E ø	E E ø	E E ø
Plastic-Laminated Chipboard	≤ 1/2" 1/2" - 1 1/8" ≥ 1 1/8"	≤12.7 12.7 - 28.575 ≥28.575	ø ø P	ø P E	P G G	G G ø	G E ø	E E ø	E E ø
Plywood, Plastics, Solid Surface	≤ 1/2" 1/2" - 1 1/8" ≥ 1 1/8"	≤12.7 mm 12.7 to 28.575 ≥28.575	ø ø G	P P E	G E P	G E ø	G E ø	E G ø	E G ø

Guidelines for MAXIMUM SAFE router bit RPM

Setup Check List

Always use a mental (or written) checklist to make sure everything is set up correctly.  Mine is a two step process to set up the router, and then to adjust the router bit, fence, and material on the table.  It goes something like this...

Disconnect power. Check bit, bearings, and collet. Ensure bit isn't bottemed out. Ensure collet is tight. Ensure spindle lock is disengaged. Ensure motor mount lock is engaged.

Set bit vertical and horizontal cut adjustments. Ensure bit clears fence and fence is tight. Check and set initial router speed settings. ROUTE!

Router Feed Direction

There's a couple of ways to remember how to feed a router, or the wood if the router is in a table.  If you learn better or can remember pics better try the pics below.  Personally, I prefer the right hand rule.  Try this... Make a little "gun" with your hand like when we were kids. Your thumb (A) will point to the fence.  Think bearing or guide bushing surface. Your middle finger (B) will point in the direction the bit protrudes through the plate. Your index finger (C) will point the way the router will travel. Got your router in a table?  Just turn your hand palm side up.  It still works... Your thumb (A) will point to the router table fence.  Your middle finger (B) will point in the direction the bit protrudes through the plate. Your index finger (C) will point the way the wood has to travel across the bit.

Route counterclockwise around the outside of the workpiece (Reverse for router table because the router is upside down.	Run the router clockwise inside of a workpiece.	Drawing shows a climb cut... Not the safest, but produces smoothest cut

Guide Bushing Information

Bits  "B" Guide 1/8 1/4 3/16 5/16 3/8 7/16 1/2 5/8 3/4 1 O.D. Max Bit "C" "C" "C" "C" "C" "C" "C" "C" "C" "C" 1/4 1/8 1/16 X X X X X X X X X 5/16 3/16 3/32 X X X X X X X X X 3/8 1/4 1/8 1/16 X X X X X X X X 7/16 5/16 5/32 3/32 1/8 1/16 X X X X X X 1/2 3/8 3/16 1/8 5/32 3/32 1/16 X X X X X 9/16 7/16 7/32 5/32 3/16 1/8 3/32 1/16 X X X X 5/8 7/16 1/4 3/16 7/32 5/32 1/8 3/32 1/16 X X X 11/16 9/16 9/32 7/32 1/4 3/16 5/32 1/8 3/32 X X X 3/4 5/8 5/16 1/4 9/32 7/32 3/16 5/32 1/8 1/16 X X 13/16 3/4 11/32 9/32 5/16 1/4 7/32 3/16 5/32 3/32 1/32 X 15/16 3/4 13/32 11/32 3/8 5/16 9/32 1/4 7/32 5/32 3/32 X 1 7/8 7/16 3/8 13/32 11/32 5/16 9/32 1/4 3/16 1/8 X 1  1/8 1 1/2 7/16 15/32 13/32 3/8 11/32 5/16 1/4 3/16 1/16 1  1/4 1  1/8 9/16 1/2 17/32 15/32 7/16 13/32 3/8 5/16 1/4 1/8 1  3/8 1  1/4 5/8 9/16 19/32 17/32 1/2 15/32 7/16 3/8 5/16 3/16 1  1/2 1  3/8 11/16 5/8 21/32 19/32 9/16 17/32 1/2 7/16 3/8 1/4

Router Bit Dimensions

First, is a diagram showing router bit dimensions to help you in determining what bit fits your particular application. D = Cutting Diameter S = Shank Diameter H = Cutting Depth I = Cutting Length R = Radius

Router Tangential Speed

Here is a little math router manufacturers use when determining the maximum safe router bit rpm speed.  A determining factor is the speed of the outer edges of bits:

Circumference = p · diameter
"Tangential" speed (in inches per minute) = circumference · rpm
So...
1" (bit diameter) · p · 18000 (rpm) = 56547in/min (4712.25 ft/min or 53.55 mph)
2" (bit diameter) · p · 18000 (rpm) = 113094in/min (9424.50 ft/min or 107.10 mph)
3" (bit diameter) · p · 18000 (rpm) = 169641in/min (14136.75 ft/min or 160.64 mph)

As you can see from the above equations, a router spinning at 18,000 rpm spins the outer edge of a 1" diameter bit at 53.55 mph.  But, the edge of that 3" bit is traveling at 160.64 mph... triple the speed by simply changing the bit.  Better hope a disentigrating bit lodges in an expensive piece of wood instead of your flesh.

Gerneral Router Safety Rules

Router Safety Resources

Routing Safe and Sound (by Pat Warner)
Dewalt 618 Series User's Manual
Safe Routing 101 (from Wood Tech)
Router Bits 101 (from Wood Tech)
Router Bit Speeds (by Tom Hintz)

To print, set to Landscape with .4" margin on all sides.