Bit slipping in the collet

I have had several projects ruined by the bit slipping during the cut. Knowing this, I try to make sure I tighten the collet sufficiently. Carbide sent a new router and collets recently while under warranty . But in the last week I have had a bit slip twice . Does anyone else experience this problem and how did you correct it

Are you using a good quality pair of wrenches?

The community has the following notes on Carbide Compact Router/Makita RT0700/0700 shaft and collet/nut wrench sizes:

  • 13mm — note that this must be low profile.
    • Bicycle cone wrenches work as well such as the 13mm Park Tool PT-09 Shop Cone Wrench
    • Asahi low profile 11/13mm wrench
    • McMaster-Carr Tight-Clearance Open-End Wrench with Black Finish, 13 mm Size, 4" Overall Length (sourced from Martin as of mid-2020)
  • 22mm — a stubby wrench is well-suited for this, and handier due to the low torque requirements


Similar thread I posted a few weeks ago

I have still been using my old collets because I have not had time to go back and experiment more.

I have been careful to clean the inside of the collet and the router shaft since this though.

Also, sometimes I put the dust shoe on for a test fit before fully tightening the collet. I often question as to whether I did go back and tighten so whenever in question I do it again.


be careful with bying bits: sometimes chinese sellers offer 6mm bits for 1/4inch diameter, but that is not the same: 6mm is only 0.23622 inch. I do not buy Amazon bits anymore since we have our “own” local maker: Dinosaw, just 10 miles away. His bits do not slip, they are precisely made, and always precisely 1/4inch. And: he re-sharpens bits too.

I tightened the collet nut with my Craftsman 7/8 open end wrench, plenty of torque. I remove and clean the collet and nut at every bit change.
( ps: the wrench’s that carbide supplies with their routers are pure JUNK)

Make sure you use 2 wrenches, not just the button and 1 wrench.

I don’t buy cheap bits. They are all C3D, Amana, IDC, etc….

In the linked thread I posted above it was a #201 from C3D with the C3D precision collets.

I think ultimately it may have been a buildup of MDF dust in the router shaft.

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The bit I was using was an IDC 1/4 inch compression bit

david: just measure the shaft of the bit, and let us know. I had some that were declared as 1/4 inch, but were 6mm.

The bit I was using was an IDC 1/4” compression endmill #CM-14. It measured .249” and 6.31mm

My bits stopped slipping when I began using a Makita router (not a knock-off) and clean the collet and nut and the inside of the router collet holder area with each bit change.


sorry, then I don’ know any further. Just happened to me.

Could the plunge rate be too fast?

Plunge rate is set at 12 inches

Clean the collet taper with a brass shotgun cleaning brush (iirc mine are 20ga with handles turned on a lathe, but a random chunk of scrap works too), and the collet with brake cleaner. If they’re sticking in the taper, common with Makita style collets, then try polishing the outside. I have a buffer in the shop but a rag and polish should do as well. After another clean give them a light coating of machine oil and wipe off. Don’t push the bit in so far it bottoms out (can’t slide further in but it can pull out), they depend on the two tapers sliding together to tighten and need a little space.

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