Router Bit Care
The following are a few suggestions on caring for your router bits and also things to check for with new router bits.
Before You Use That New Bit
First, when unpacking a new bit, check to see that the bearing rolls freely. Then check to see that it is tight. Sometimes you will find a holding screw that is just finger tight. Use a key to tighten it. Check the carbide cutting edge for possible fractures. Also check the shank to make sure it is smooth with no burrs or rough spots. Always check a new bit to make sure there is good clearance between the carbide cutting edge and the bit body/
Never use a dull or chipped router bit and always replace damaged bearings. The shank of a good router bit will always bend before it breaks. Your first indication will be a wobble. If you get a wobble with a particular bit, DON'T use that bit any more. Bottom the bit in the chuck, but before tightening it in place, lift it up about 1/8'. When cutting, bits generate a lot of heat. If they are bottomed in the chuck this heat is transferred directly to the router motor. This causes premature burnout.
Hints on Carbide
Solid carbide bits are very brittle and require special care. Any jamb while working may cause the bit to break. Be careful never to hit a solid carbide bit with a wrench while chucking it up. Make sure only the smooth surface of the shank contacts the collet and never chuck up with any part of the milling surface in the chuck. The best storage is one that keeps the bits clean, dry and secured without touching each other. Drill shank holes in a storage bottom so that the bits remain upright and clear of each other.
Keep the bits clean of resin. Resin build up causes burning. If a bit is stuck in a chuck a stiff tap will often jar it loose. Use a piece of wood, not a metal tool, to tap the bit and be careful not to tap the carbide cutting edge. If you have a bit that is constantly coming loose, try another bit. It may be that the shank is out of round or slightly undersized, a problem that is exaggerated when using a reducing sleeve in a 1/2' chuck. When using a split sleeve, be sure that the split in the sleeve lines up with the split in the collet.