why does my router

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Forum topic by britchic posted 03-26-2018 09:03 PM 1316 views 0 times favorited 25 replies Add to Favorites Watch
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25 posts in 843 days

03-26-2018 09:03 PM

can anyone help me?
I was using my router and the bit came loose. I stopped to tighten it and it did the same thing when I tried using it again. Does anyone know why it does this?
I ended up putting it in the table base and routing the piece that way, but I’d still like to know why it was loosening. Was it something I did. or didn’t do? Or from the tool heating up??

25 replies so far

View Redoak49's profile


4755 posts in 2767 days

#1 posted 03-26-2018 09:07 PM

It would be helpful to know what router, what router bit and what you were cutting. Without any details, all you will get is guesses.

View pintodeluxe's profile


6159 posts in 3592 days

#2 posted 03-26-2018 09:08 PM

You could have a fractured or worn out router collet. I replace mine from time to time, or if I notice a crack in them.

Some brands of routers have better collet designs than others. I like the modern double-locking one-piece style collet. The type I won’t use is a large collet with an insert sleeve. Those are prone to slipping, especially when using bits with 1/4” shanks.

One other possible cause… some cheap bits are actually out of spec and may not be actual .25” or .50” shank size.

-- Willie, Washington "If You Choose Not To Decide, You Still Have Made a Choice" - Rush

View DS's profile


3503 posts in 3199 days

#3 posted 03-26-2018 09:15 PM

+1 to dirty, worn, or sprung collet. This is a common culprit in a situation like this.

Of course, a router bit with possibly a bent, or, out-of-round, or, mismatched (metric vs imperical) shank can cause it too, but, these would be fairly unlikely. (Is it a brand new bit?)

-- "Hard work is not defined by the difficulty of the task as much as a person's desire to perform it.", DS251

View msinc's profile


567 posts in 1282 days

#4 posted 03-26-2018 09:20 PM

Not saying this is necessarily what is going on with your router, but mine did the same thing once. I have a Bosch with the so called “self ejecting” collet. The other day I was using it and had to have the bit slightly further out of the collet than I would normally run it. It still seemed like it should have been plenty of shank in the collet to work and stay tight, but no. Mine did exactly what you are describing. It seemed to tighten up when I snugged down the collet, but it would quickly loosen as soon as I began to rout. The router bit spun in the collet when it loosened and then it really didn’t want to be tightened. The only way I could use that particular bit in that collet was to install it about as deep into the collet as it would go and only then would it stay tight.
I don’t know if this is something that has to do with that self ejecting collet feature or not. While it is nice and that part works great, I never had this problem with my old router. I could pretty much stick a bit in it and set it anywhere in the collet I wanted and it would stay nice and tight and work fine. Just to clarify, the “self ejecting” collet means that to change or remove a bit you just keep on loosening the collet nut and it will kind of hit a hard spot. You continue to loosen a little more by forcing the wrench and the bit will release and fall out.

View britchic's profile


25 posts in 843 days

#5 posted 03-26-2018 09:24 PM

It’s a Craftsman router – I think 1 3/4 HP that uses either 1/4 or 1/2 ” collet.
I was using 1/4” collet with a 3/8” corner round bit (not used before) on an 8’ 2×12 board that I’m using to make a skinny sofa table

View mpsprunger's profile


34 posts in 2640 days

#6 posted 03-26-2018 09:27 PM

Time to change collet, mine did the same thing

View johnstoneb's profile


3145 posts in 2952 days

#7 posted 03-26-2018 09:29 PM

clean the collet

-- Bruce, Boise, ID

View britchic's profile


25 posts in 843 days

#8 posted 03-26-2018 09:32 PM

Thank you – I’ll try cleaning/changing the collet.

View firefighterontheside's profile


21058 posts in 2635 days

#9 posted 03-26-2018 09:33 PM

What kind of bit was it. I’ve had my router let go of solid carbide bits before. The carbide is so hard, the steel collet can’t hold onto it unless it’s really tight.

-- Bill M. "People change, walnut doesn't" by Gene.

View LesB's profile


2561 posts in 4222 days

#10 posted 03-26-2018 09:36 PM

One thing that can affect the tightening of the collet is if you insert the stem of the bit all the way to the bottom of the routers output shaft. That prevents the collet from properly tightening because the collet is moving down as the nut tightens. So give the stem of the bit a little space so it can move with the collet during the tightening process.

-- Les B, Oregon

View Loren's profile


10477 posts in 4427 days

#11 posted 03-26-2018 09:55 PM

Bit shanks vary a little bit in thickness. I have
some that are so wide they always get jammed
in my trim router (which doesn’t have a very
well designed collet either).

I have also had bits drop out when using a router.
I learned to tighten the collet better. I apply enough
pressure that I always hold my breath and grunt.

View Alex Lane's profile

Alex Lane

574 posts in 4669 days

#12 posted 03-26-2018 11:04 PM

I wonder if you very lightly scuff the shank with sandpaper if it might grip in the collet better

-- Alex...builder of wooden wings for vintage sport biplanes...I'm your wingman :)

View splintergroup's profile


3801 posts in 2001 days

#13 posted 03-27-2018 04:10 PM

I have a Craftsman router from the late 70’s and these were notorious for their self-adjusting depth “feature”.

Basically one had to really crank down on the collet nut to secure the bit.

View AxkMan's profile


65 posts in 905 days

#14 posted 03-28-2018 01:56 AM

1) Check the bolt screw on the latch cover that locks it when you change bits. If this screw is loose then that is the problem. Adjust slightly checking for any loose nuts as this needs to be maintained.

2) Do not place the bit all the way in the collet. Leave 1/16” – 1/8” from the bottom. Push all the way in, then pull up a bit.

3) Do not adjust the collet too tightly, but make sure you use the wrench as securely as possible. Very firmly but not hard.

4) Check the shaft of the bit for scratch marks. If this is the case, there are most likely scratch marks on the collet nut and other bit shafts. This can cause unwanted friction.

5) Clean the bits of any debris. Even around the cutting blades (safely). This causes unwanted friction.

6) Adjust speeds properly, do not move fast. Especially when using large bits like 1/2” and wider blades. The wood is causing too much grip in this instance and bad on the motor. Not only would something like that happen, but ruin the motor. Pace yourself knowingly.

View PPK's profile


1752 posts in 1588 days

#15 posted 04-06-2018 06:43 PM

Please be really cautious whatever you do… router bits that come flying out of a router spinning at +/- 30,000 rpm can do a lot of damage to the body. I have had a bit fly out of a router and go zinging past my ear.

-- Pete

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