How to Install a Router Bit

The logic behind a fairly simple process!

Difficulty: Moderate

Instructions

1. The first step is crucial: BOTTOM OUT THE ROUTER BIT IN THE COLLET. Withdraw it 1/16" to 1/8" before you tighten the collet nut. Why? Not because it will reduce vibration; not to cut down on heat transfer. The reason is this: When you tighten your collet nut, the growing taper of the cone is being driven into the corresponding shrinking taper that has been milled into the end of the motor spindle. The result is a collet squeezed against the router bit shank. The friction locks the bit into place, and now the bit won't be able to twist or pull out as you're going along.

2. If you bottom out the pit and pull back on it, the collet cone can take hold of the shank and bring the bit with it, while both the cone and the bit get driven further into the spindle, locking tighter -- but in the right way. So, bottom out the router bit, pull it back about 1/8", and then you're ready to go.

3. How tight is too tight? Use your wrench firmly, but stop just before you get the idea that you can twist it on in an unbreakable grip. If you overtighten now, the mouth of the spindle will get stretched, and it won't be able to safely hold any bit. New routers are a lot more expensive to buy than new router bits are! Now you're done!

Tips & Warnings

• NOTE: Many of the new, top-of-the-line routers don't need this special rule about bottoming out. The Makita and DeWalt plunge routers are examples, because they have the motor spindle drilled well past the one-inch mark. This eliminates the problem with bit installation, but makes it tricky to figure out how much shank is inside the collet at any given time. To solve this new problem, just slide the bit shank as far as the collet's grip (generally 3/4" or more) to make sure that you have control. A black line drawn on your bit shanks can save you a world of hurt.
• If you have a 1/2"-collet router that needs adapter sleeves instead of replacement collets for smaller shanks, handle the adapter just like you would if it were a bit. Give both the adapter and the shank room to move deeper into the collet when the nut is tightened.