Author Patrick Spielman, writing in The New Router Handbook, notes that in addition to protection from the usual hazards of flying chips, noise, and dust the following safety precautions should be heeded faithfully when operating a router:
1. Read your owner's list
2. Make sure that you have selected the proper bit. Check the type, shank strength, cutting length and diameter, and sharpness of the bit.
3. Make sure that the router horsepower and speed is appropriately matched to the material, the intended depth of cut, and the size of the bit selected.
4. Always disconnect the power when changing bits, servicing the router, or mounting attachments.
5. Make sure that all bits, attachments, clamps, and locking devices are secured before starting the router.
6. Make sure that the on-off switch is off before connecting the power.
7. Dress properly. Wear eye-, hearing-, and dust protection devices, and either short-sleeve shirts or long-sleeve shirts with rolled-up cuffs. Wear a shop apron or tight clothing. Make sure that your hair, jewelry, etc., will not become entangled with any moving parts of the router.
8. Keep children and observers at a safe distance.
9. Make certain that all workpieces are securely clamped and will not shift during routing.
10. Always grip the tool tightly, especially when starting up the router; when you have to resist the initial motor torque. Keep both hands on the knobs or handle, or use a foot switch when the job requires a "third hand".
11. Be especially cautious when routing small pieces. Make test cuts in solid unchecked stock of a safe size.
12. Be absolutely certain that the bit is not in contact with the workpiece and that no part of it will strike the wood when you are turning on the power.
13. Develop the habit of turning off the router immediately after you have switched it on. As the motor starts to coast down, use your eyes, ears, and sense of touch to detect any unfamiliar conditions or irregularities.
14. Always shut the power off immediately at the first sign of any unfamiliar noise or vibration. Always be aware of the feeling in the handles and the "hum" (that can even be heard through hearing protectors) that indicates the router is operating properly.
15. Do not operate electric routers in moist, wet areas or damp environments.
16. Do not use mounted abrasives, carving burrs, drills, or other non-routing tools and cutters in routers just because they have shanks that are the same size as your router's collet.
17. If the router or work tends to ride upwards and requires extra pressure to feed, turn off the power immediately. This indicates the bit is dull, it is slipping out of the collet, or just that you have selected the wrong bit design.
18. Don't force-feed the router or work in any situation.
19. Do not try to increase the bit's depth of cut by inserting less of the shank in the collet. Most bits should have at least 3/4 of their shank length inserted into the collet.
20. Always feed the hand-held router into the work in the correct direction, against the bit rotation. In router table use, feed the workpiece in the direction that is also against the bit rotation.
21. Maintain your router equipment diligently. Replace worn parts, discard worn-out and poor bits, and check the router periodically.
This article is excerpted from The New Router handbook by Patrick Speilman--Published by Sterling Publishing 1993.