How deep should router bit be in the collet?

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Forum topic by Carloz posted 06-09-2017 02:57 PM 5610 views 0 times favorited 10 replies Add to Favorites Watch
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06-09-2017 02:57 PM

There is a lot of information that router bit should be inserted almost as deep as it goes minus some small gap 1/16” or so. However if I do that with my Bosch router the carbide flutes sit deep in the collet. I have to pull it out more than half inch just to clear the carbide. Then I start wondering how safe it is to keep it that shallow. Any thiughts, i use whiteside and freud bits.

10 replies so far

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#1 posted 06-09-2017 03:09 PM

If you look at your collet, you can see the jaws that do the actual clamping. As long as the bit is fully engaged in those jaws the bit is deep enough – at least for the consideration of the collet clamping the bit.

Whenever possible, the guideline you shared is preferred. You want the forces of cutting as close to the collet as possible.

-- Steve - Impatience is Expensive

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#2 posted 06-09-2017 03:10 PM

You should at least push the bit shank in far enough to fully engage the clamping surface of the collet jaws.

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Fred Hargis

6247 posts in 3270 days

#3 posted 06-09-2017 03:11 PM

Seems like I remember Charles (from Freud) saying that at least 2/3s of the shank should be in the collet. If that’s not right someone will remember. I do know you don’t set the flutes into the collet, and I’ve never heard a recommendation to seat it as deep as possible. On my Milwaukee routers the hole is deeper than some of the bits are long.

-- Our village hasn't lost it's idiot, he was elected to congress.

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1377 posts in 1686 days

#4 posted 06-09-2017 03:13 PM

How to Install a Router Bit

-- "You know, I'm such a great driver, it's incomprehensible that they took my license away." --Vince Ricardo

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#5 posted 06-09-2017 03:18 PM

I always put it in all the way, then bring it out 1/16” or so.

-- Genghis Khan and his brother Don, couldn't keep on keeping on...

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#6 posted 06-09-2017 03:47 PM

I put O-rings on the shaft just below the start of the curve under the cutter. Makes it easy to set the bit and acts as a 3rd hand so the bit doesn’t slip while tightening.


-- The hump with the stump and the pump!

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#7 posted 06-09-2017 04:02 PM

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#8 posted 06-09-2017 04:16 PM

Here’s one visual aid from Tork Craft:

-- Happiness is like wetting your pants...everyone can see it, but only you can feel the warmth....

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115 posts in 1220 days

#9 posted 06-09-2017 07:02 PM

If you use Zip-Strip or some other degreaser on your collet and router shank, get everything absolutely clean and dry, you’ll minimize the chances of the cutter pulling out during operation.

Another simple trick is to put marker around the collet/shank junction to watch for cutter movement. It’s easy to see the white metal above the marker if the cutter starts to pull out. The idea here is to minimize the damage of movement.


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1368 posts in 1697 days

#10 posted 06-10-2017 02:24 AM


The 8th bullet under the heading “General Guidelines, Tips, and Safety” on page 3 of the MLCS Technical Manual advises that at least ¾” of the router bit shank should be installed in the collet.

BigYin mentioned a router collet extension. On page 23, MLCS technical Manual also discusses the router collet extension and it use

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