Broken router bit

[pigman]

I was doing some wood working this morning and I was very lucky. After some setup and test cuts I turned around to pick up the trim I was going to rout with the 1" roundover bit in my router table when I heard an explosion. One of the cutting edges of the bit broke loose and flew into the side of the table opening and was struck by the other cutting edge. I can only imagine what it would have felt like if that broken cuting edge had hit me.

[Paschale]

Yikes!  That proves once again that our woodworking tools need to have our respect! 

Was it an old bit?  What do you attribute the flaw to?  Was it one of the major brands of router manufacturers? 

I've seen router bits at Harbor Freight and the like and they make me nervous.  But no company makes perfect anything, but that sure is scary to think about what it could have done.   

[Don P]

I had that happen with a top head chairrail cutterhead once. The 4" wide face popped off from a bad braze and then hit the other two wings. One chunk was buried in a wrench beside my hip.
I took a long break  :D

[tyb525]

That's something I hope to never experience! 

[WDH]

That high pitched whine of the router is scary enough without the bits exploding as shrapnel .

Bob, that scares me just reading about it, and I am sure that it scared the DanG out of you.

[pigman]

Was it an old bit?  What do you attribute the flaw to?  Was it one of the major brands of router manufacturers? 

I found the bit in a box of parts for a used shaper I bought a few years ago. I don't know the brand or the age. It seemed to be a good sharp bit, but I only used it a few times because of it's size. I had a shaper panel raiser lose part it's carbide last year. That was because I let a metal hold down get loose and contact the cutter. I was lucky that time also and didn't get hit. One of these days if I don't start  paying attention, my luck is going to run out. :

[tyb525]

Boy, I'll make sure to not buy cheap bits if I can help it. Unfortunatley my first set (and biggest) was from menards :-\.
I remember the first time I heard a router. Scared me pretty good.

[SwampDonkey]

I've bent the shaft of a bit before, actually two and the same brand. I sent the junk back and warned them of their product. I ended up with a 3rd one for replacement.  : I was routing a piece of ash, hard stuff. And weeeeeeeeeeeerrrrrrrrrrr!!!!  Good thing there is a 3 inch wide kill switch on the table, you can stand back behind a 10 foot pole and poke the switch.  :D

[DR Buck]

Bob...your scarin' me.   

            KNOCK IT OFF !

[Texas Ranger]

I had two of the  Freud door combo bits go to pieces, at $250 a set, they were made good by freud, but, even the good ones have bad days.

[tyb525]

Is there any kind of maintenance to prevent this? Wear bulletproof clothing when routing?

[logwalker]

And just think...most of the time you are using a router it is at belt level or a little lower.  ;)

[LeeB]

I had one break off the shank. Grazed my finger on the way by. It was a cheaper one with a 1/4" shank. 1/2" cove bit. I think it just got hot and got weak. I had been running it hard just before it turned loose.

[Texas Ranger]

Half inch shank if you use them a lot, then only the carbide, bearing, etc, can come lose.

[SwampDonkey]

On my table I use only 1/2" shank. On my hand held I use 1/4" shank. It was 1/2" shank bits I bent.  :

[Larry]

Years ago I ran an Onsrud overarm router in a production (before OSHA) environment.  At the time we used solid carbide straight bits for pattern routing.  If the bit got dull or if I had a full load of Wheaties in the morning it would not be unusual to break a bit.  Guess I was lucky because I never had a broken bit draw blood.

On another note I have a shaper with a head that I run inserted bits in...some are home made.  I keep a 4 X 4 wood block in front of the cutter when I turn the shaper on just in case it wants to throw a bit.  I also wear a heavy leather apron to protect my body parts...just in case.  My apron is getting a little frayed...only bout 50 years old so I have been looking for a new one.  Thought next time I get to Grizzly I would check this one out to see iffen it is a suitable replacement.

http://www.grizzly.com/products/h7435

You guys running those big bits in a router table scare me...I would much rather use the shaper.

[pigman]

Larry, I was running the big round over in a variable speed router and it was only turning about 8,000 rpm 
I once had the  big  panel raiser in the router table and forgot to turn down the speed . That thing was really humming at 20.000 rpm.   I got it turned off before parts started flying off.
 

[LeeB]

You guys running those big bits in a router table scare me...I would much rather use the shaper.

I recon most of us would too. To much dust in my pockets and none of it precious metal. :D

[CHARLIE]

Carbide is so hard it's brittle. If you ever drop a router bit, you aren't supposed to use it again because the carbide could have a hairline crack and come apart later.

Story I read 15 or 20 years ago was that a man was found dead in his shop. What happened was a carbide tooth came off his tablesaw blade and hit him in the head just into the hairline. At first they couldn't determine why he had died 'cause the hole was so small.

[cheyenne]

By the looks of the bit pocket it was probley an air bubble or a piece of dirt. Even a fingerprint before brazing will make them blow. If you want to see how carbide can react heat up the old bit cherry red with a torch & dip it in a big can of water. (safty glasses please) Be careful.....Cheyenne