every craftsmans nightmare

I have a stack of balsa guns that were shaped by Lyle Carlson, started chambering the first one this week, was nearing completion when my routers speed suddenly increased and it slid forward with too much ease.

Over the years I have had the collet lossen up from vibration and drop the bit out he bottom while routing, not the case, bit a half inch, tool steel with carbide tips, snapped off right at the collet, Holy F’n BatShit, a 9 thousand RPM grenade

Holy Smokes!!! That is litterally dodging a bullet. Scary Sh$%. What make was the bit? Do you seat the bit all the way down in the collet or drop it to the bottom and then pull up a tiny bit to give space? This makes the bit concentric with the rotation and won’t work loose. Have heard of this happening but never experienced it. I’ve been a woodworker for 39 years and so far so good. That one probably added to the grey hair count. All the Best.



If you work around power tools long enough shite will happen and a bit of luck is always a good thing.

Was it kept captive in the mortise or did it plow thru’ and screw up the work?

  What brand was the bit?     

How long was the bit in the router?  It may have just sheared off at the collet from excess stress.

That looks to be a 1/2 inch shank.       Verrrry scarey.          Glad you’re OK.

Over my years in the machine shop I’ve seen quite a few broken or blown up cutter, even done a few myself… 

Never fun. Glad the picture wasn’t followed by damaged body parts. 

As they say… Safety never takes a vacation haha 

Jim, you didn’t mention anything about escaping without injury. I hope you did.

Had a similar situation occur.

Was routing out a longbox hole, when suddenly a loud noise and the F’n bit went through the deck onto the floor and recocheted all around my feet and off the walls.

Porter cable router at about 15,000 RPM’s.

Holy Shit!

Left a big dirty note on the wall. I was beyond pissed!

Somebody had used it and did not replace the tool the way they found it.

Turned out to be Gary Linden.

He apologized.

To this day, I tell people the router is the most dangerous tool in the surfboard factory.

Glad you’re OK Jim.

Close one.

Who made the bit?  I’m surely going to stay away from that brand.

I had something similar. They told me it can ocure when hardend steel bits or other tools are dropped on a floor. Crack s can appear en it can break al of a sudden.

I’m fine, the bit stayed in the route, lost momentum instantly, don’t remember that brand, I use a lot of Amana bits, it was at least 20 years old, but not abused, the carbide inserts were still sharp as hell. The cut was 3/4" deep in med density balsa. The bit was sunk full depth into the collet with a shaft and cutter portion only 2-1/2". I should buy a lottery ticket today

I seem to recall a similar story when someone used a drill bit in a router.  Luckily you wear eye protection and a cup.  Did I just hear that prices just went up for clambering?


Has the bit always been black like that? Looks like it’s the same color all the way through. has it gotten really hot?  20 years of use is a lot to ask even if used carefully, that’s a LOT of revolutions. May have just been fatigue. Either way, scary shite. I’ve had bits come loose before but only seen them break in a cnc and they just tend to get stuck in the work. I always try to stay on the opposite side of whatever I’m routing because of the very thing that happened to you.

If the bit was seated all the way down in the collet and bottomed out, that may be the problem. There should always be a space between bottom of shank and router. A trick I was taught was to take a small O-ring and put it in the collet to the bottom. This automatically indexes the shank to turn without hanging up. When a lateral force is applied, the shank can get stressed over time. When the bottom is locked in and can’t move this creates a “hinge” point at top of collet. Over time a weakness can develop right where it clamps the shank. Amana makes very good bits but after 20 years? I have bits that old or older but no problems. Might have to take a look, Glad to hear you are okay.

This happened to me when I was routing channels into posts for an oak post-n-beam frame of a house. Electrician needed a path for his wiring before the skins went on. Brand new 1/2" straight cut bit and halfway through the first pass of 8’ (+ or -) the damn bit snapped at the shaft. Depth of cut was about 5/8". After cursing in two or three languages I swapped out the bit and the rest went fine. Must have been a defective one?

Scary indeed.  A while back I bought a router speed controller, primarily to slow down an Angle grinder with flap sander to foil fins, but found it useful in slowing older box fans, and belt sander.



 Later, When I used it on my router on a non surfboard related with same shape and shaft bit as shown in OP task I was surprised how reduction in rpm did not really slow wood removal, and it increased control.


Was the work damaged badly, How far did the broken end fly?


9K rpm is much slower than the ~31K rpm at max speed of most routers, so I assume you had slowed your router speed too?


Think this was a contributing factor?


Carbide, super sharp,super brittle… 20 year old.    Anyhow your old tough skin it would have just bounced off and stuck into the wall,… like one of those throwing stars things

Good to hear you didn’t get hurt. So many tools we use that can cause problems even when we use them properly.