# Bit into spindle ?



## sawnsand (Feb 10, 2016)

Is there a set length or a suggested length of the bit that needs to be up into the collet? A percentage of the length of a bit?


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## kp91 (Sep 10, 2004)

2 rules I've lived by for routing...

-Never bottom out a bit. If you put the bit in too far, then the collet cannot pull down on it properly to tighten. It can also score the bit.

-The bit has to be fully through the collet. Make sure the bit passes all the way into the collet, so it can get a solid grip. I personally try to put as much bit into the collet as possible and still accomplish the job. I don't know if it is scientific, but I think the shorter bit extension (or 'lever arm') puts less stress on the router or spindle bearing. I guess you could think of it as a cantilevered load.


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## RainMan 2.0 (May 6, 2014)

Courtesy of Harrysin . Harry posted this info and it covers differant routers. 

http://www.routerforums.com/attachm...r-insert-bit-question-often-asked-members.pdf

I'm with Doug though , do not bottom out the bit , and I've even heard of people putting a rubber O ring in the bottom of the collet to prevent this


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## DesertRatTom (Jul 3, 2012)

I always use the half inch grommet trick. Drop it into the collet and let the bit bottom out on it. Works like a charm.


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## 4DThinker (Feb 16, 2014)

The minimum of the shaft I make sure is in the collet is enough to fill the inner tapered plug of the collet. 

If your bit is wider than the shaft and has a fillet where the shaft meets the wider sharpened parts make sure you aren't clamping down on that fillet. 

4D


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## Cherryville Chuck (Sep 28, 2010)

As Doug said, use 100% of the collet. Somewhere around 75 or 80% or less and you risk damaging the collet. More than 100% through doesn't gain anything holding wise but as Doug said it causes less shear force on the shank and less stress on the bottom bearing. If you notice, 1/4 shanks are usually fairly short and that's not an accident.


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## Knothead47 (Feb 10, 2010)

Rainman, thanks for the link. Never really thought of the question posed here.
Harry, thanks for doing the research!


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## rwl7532 (Sep 8, 2011)

I threw a rubber grommet into the hole and I'm done with it.


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## OPG3 (Jan 9, 2011)

I've gotten into the habit of removing the collet entirely - separate from the router, and then inserting the bit until I can see there is 1/8" of free space within the collet and below the bit shank. Next, I just put the collet together and tighten with the two wrenches provided by Porter-Cable and I'm using P-C 690's.

Otis Guillebeau from Auburn, Georgia


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## SteveMI (May 29, 2011)

I am the voice of bad experience, bottomed out a bit and tightened it up. Took quite an effort to loosen the collet after that.

Now I bottom it and bring it out 1/4" before tightening.

Steve.


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