81 - Ultimate Sharpening Station, страница 8

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get a grip on

Note; Fillet of Bit Should Not Touch

Collet Nut ^ToP ^{of Collet} Locks Collet in Arbor'

Router Arbor Accepts Collet

and Pit

Collets

Often overlooked, this router component plays an important role.

One of the key parts of any router is the mechanism that holds the bit in place — the collet. It's easy to change router bits without even giving this part a second thought. But once the bit slips or is hard to get in or out, it's sure to get your attention.

How it Works. The illustration above shows you how a typical collet works. As you can see, it's a tapered sleeve that's precisely machined to fit in a socket in the end of the arbor. Then as you

tighten the nut that fits on the end of the arbor, the collet squeezes the shank of the bit and holds it firmly in place. This means that anything that interferes with these parts (like debris and burrs) affects how well the collet holds onto the bit.

You'll find that most collets work in a similar manner. But some collets are made just a little bit different than others.

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Split Arbor Collet Nut

Collet Squeezes Bit Shank

Collet Types. Two of the routers shown in the photo below have split collets. You'll see them with single splits or multiple segment splits.

As a rule, more segments tend to grip the bit more uniformly. But the greatest advantage of this type of collet is that if it wears out, it's easy to take it out and replace it with a completely new one.

The other type of collet you'll see is like the one on the router in the upper right in the photo below. This collet is machined right into the router arbor or motor shaft. You'll usually find these on less expensive routers. The problem with this one is that when the collet becomes damaged or wears out, you'll have to replace the entire router and not just the collet.

Collet Sizes. You'll usually find collets in either tyi" or diameters to match the shank of the bit. Some manufacturers will ship routers with both sizes or with a V2" collet and include a Vi" reducer.

Both sizes get the job done. But I like to use the larger %"-dia. size because it has a lot more surface area to grab onto the bit. Whichever size you use, you'll find there are a few things you need to know before you're ready to put the bit into the collet.

8 ShopNotes No. 81