Broken Carbide Router Bit

judaspre1982 · Post by **judaspre1982** » Tue Sep 21, 2010 7:39 pm

==========================
DT aka Agent Orange is a POS
Liar Liar his wonky comb over is on fire

charlese · Post by **charlese** » Tue Sep 21, 2010 10:09 pm

Nope! Been lucky enough to not have any router bits come apart. A long time ago I did have a carbide tooth from the saw blade in the SS biscuit jointer break. Shopsmith replaced it, no questions asked. It was only a month old at the time.

I have read about different hardness grades of carbide. Maybe it is not an exact process and some pieces get too brittle

.

a1gutterman · Post by **a1gutterman** » Wed Sep 22, 2010 11:21 am

Like charlese, that has knot happened to me either. I have never purchased inexpensive router bits, though, and I feel that is what has saved me from your experience. What Chuck says about the hardness is correct. The cheaper bits might/might knot be a good quality carbide.

mbcabinetmaker · Post by **mbcabinetmaker** » Wed Sep 22, 2010 7:28 pm

a1gutterman wrote:Like charlese, that has knot happened to me either. I have never purchased inexpensive router bits, though, and I feel that is what has saved me from your experience. What Chuck says about the hardness is correct. The cheaper bits might/might knot be a good quality carbide.

I once opened a newly purchased Freud round over bit and when I pealed the protective crap off I discovered that about half of one side of the cutter was broken off. It actually looked like someone had dropped it. The guy that I buy most of my bits and blades from exchanged it but I am not sure he believed that I did not damage it myself. I guess S#$% happens in the best of families.

oldc6 · Post by **oldc6** » Wed Sep 22, 2010 8:34 pm

Look at the thickness and heft of the carbide on the cheaper bits....... This is one instance that you get what you pay for. Something that is spinning at 25 to 30,000 RPM I want the good stuff in the collet.........

mickyd · Post by **mickyd** » Thu Sep 23, 2010 3:27 pm

judaspre1982 wrote:Has anyone ever had this happen to one of their router bits?
[ATTACH]10457[/ATTACH]

[ATTACH]10458[/ATTACH]

I was routing a 1/4in w x 5/8 d groove in a piece of 1x2 red oak10 in long.
I made 3 passes a little over 1/8 in deep each. After the last pass I noticed the bit had broken. ......

Don't forget our resident stress engineer horologist (aka Troy). He'd probably love to see some nice close up shots.

judaspre1982 · Post by **judaspre1982** » Thu Sep 23, 2010 5:16 pm

===============================

horologist · Post by **horologist** » Thu Sep 23, 2010 10:54 pm

Dave,

For what it is worth, I gave it some thought as I went to drop my Jeep off for service, I do all sorts of problem solving while driving. The most likely cause I came up with is exactly what you describe. Carbide is brittle stuff and with a weak connection between the carbide and the bit shaft the unsupported portion of the carbide would be susceptible to breakage.

This is one more example of how cheap cutting tools are frequently no bargain. Not only do you risk injury, but you could also ruin your work as well. I once got suckered into buying some cheap drill bits (Chinese) the first time I tried to use one it bent and twisted, ruining my part and costing me several hours of careful machining.

The good news is that if you have already used the other bits then they are probably OK as this sort of failure would happen very quickly. Also, there will be no appreciable difference in life between cutting hard or soft wood.

Troy

judaspre1982 · Post by **judaspre1982** » Thu Sep 23, 2010 11:59 pm

=========================

tnerb · Post by **tnerb** » Fri Sep 24, 2010 12:58 am

judaspre1982 wrote:Has anyone ever had this happen to one of their router bits?
[ATTACH]10457[/ATTACH]

[ATTACH]10458[/ATTACH]

I was routing a 1/4in w x 5/8 d groove in a piece of 1x2 red oak10 in long.
I made 3 passes a little over 1/8 in deep each. After the last pass I noticed the bit had broken. This bit was brand new, never used. I didn't have any chatter or excessive vibration during any of the passes.
This bit came in a multi-bit case, which I bought about 6 years ago. I have used most of the bits in the set , some dozens of times in much harder wood with no problems. It looks like the carbide cutter may not have been brazed as well as it should have been to the shaft, IMO.
The bit set was not very expensive, but I have been happy with the set up to this point. I may now reserve this set to soft woods from now on , and buy some better quality bits a little at a time when funds become available.
Dave

Yup! I had a 1/4" carbide bit with a 1/2" shank break off on two bits, in the same place, from the same manufacturer.

I now stay away from that manufacturers router bits.

I was routing a groove 1/4" deep in softwood both times.

Brent