So there I was routing a 15" long 5/16 deep slot in some hard maple with
a 1/4 inch bit on a 1/2 inch shank and 12 inches into the cut the bit
sheared. This bit was one of those green Woodcraft bits that they put
on sale from time to time. I was using a pretty slow feed rate, but my
guess is that the bit failed due to heat. Any thoughts?

Larry

On Sat, 08 Oct 2011 16:05:57 -0500, Gramp's shop
wrote:

So there I was routing a 15" long 5/16 deep slot in some hard maple with
a 1/4 inch bit on a 1/2 inch shank and 12 inches into the cut the bit
sheared. This bit was one of those green Woodcraft bits that they put
on sale from time to time. I was using a pretty slow feed rate, but my
guess is that the bit failed due to heat. Any thoughts?

Larry

I go by the rule that the depth of the cut should never be more than
the diameter of the cutter.
--
Jack Novak
Buffalo, NY - USA

On Oct 8, 4:17*pm, Nova wrote:
On Sat, 08 Oct 2011 16:05:57 -0500, Gramp's shop
wrote:

So there I was routing a 15" long 5/16 deep slot in some hard maple with
a 1/4 inch bit on a 1/2 inch shank and 12 inches into the cut the bit
sheared. *This bit was one of those green Woodcraft bits that they put
on sale from time to time. *I was using a pretty slow feed rate, but my
guess is that the bit failed due to heat. *Any thoughts?

Larry

I go by the rule that the depth of the cut should never be more than
the diameter of the cutter.
--
Jack Novak
Buffalo, NY - USA

I take shallow passes too. But I also have to wonder if the bit was
defective. How old was it.

This is one reason I transitioned over to 1/2" shank bits. I had a
1/4" bit fail several years ago and felt a little lucky I didn't get
hurt.

RonB

On Sat, 08 Oct 2011 16:05:57 -0500, Gramp's shop
wrote:

So there I was routing a 15" long 5/16 deep slot in some hard maple with
a 1/4 inch bit on a 1/2 inch shank and 12 inches into the cut the bit
sheared. This bit was one of those green Woodcraft bits that they put
on sale from time to time. I was using a pretty slow feed rate, but my
guess is that the bit failed due to heat. Any thoughts?

Larry

How deep the cut? Any burning on the wood? Did the cutting edges
fail or looked burned? Or did the bit shear off below the cutters?
Was it sharp?

Inquiring minds want to know.

-Zz

On 10/8/11 4:05 PM, Gramp's shop wrote:
So there I was routing a 15" long 5/16 deep slot in some hard maple with
a 1/4 inch bit on a 1/2 inch shank and 12 inches into the cut the bit
sheared. This bit was one of those green Woodcraft bits that they put on
sale from time to time. I was using a pretty slow feed rate, but my
guess is that the bit failed due to heat. Any thoughts?

Larry

Bad bit. 5/16" *is* a shallow pass.


--

-MIKE-

"Playing is not something I do at night, it's my function in life"
--Elvin Jones (1927-2004)
--
http://mikedrums.com

---remove "DOT" ^^^^ to reply

On 10/8/2011 4:05 PM, Gramp's shop wrote:
So there I was routing a 15" long 5/16 deep slot in some hard maple with
a 1/4 inch bit on a 1/2 inch shank and 12 inches into the cut the bit
sheared. This bit was one of those green Woodcraft bits that they put on
sale from time to time. I was using a pretty slow feed rate, but my
guess is that the bit failed due to heat. Any thoughts?

Larry

Sounds like you might have been cutting too deep, especially in hard
maple. I would have made it in 2 passes.

"Gramp's shop" wrote in message ...

So there I was routing a 15" long 5/16 deep slot in some hard maple with
a 1/4 inch bit on a 1/2 inch shank and 12 inches into the cut the bit
sheared. This bit was one of those green Woodcraft bits that they put
on sale from time to time. I was using a pretty slow feed rate, but my
guess is that the bit failed due to heat. Any thoughts?
-------------------------------------------------------------------------------------------------

If it was cutting full diameter, that is the hardest cut a router bit can
do. Depth should be half the diameter for a cut like that. A 1/4 inch cutter
does not benefit by a 1/2 inch shank. The transition in cross section sets
up a stress riser that negates the advantage of the larger shank.

The cuts was 5/16 deep. No burning on the wood. Cutting edges still
look good. Bit sheared off below the cutters. Factory sharp carbide
with very little use up to now.

On 10/8/2011 5:32 PM, Zz Yzx wrote:
On Sat, 08 Oct 2011 16:05:57 -0500, Gramp's
wrote:

So there I was routing a 15" long 5/16 deep slot in some hard maple with
a 1/4 inch bit on a 1/2 inch shank and 12 inches into the cut the bit
sheared. This bit was one of those green Woodcraft bits that they put
on sale from time to time. I was using a pretty slow feed rate, but my
guess is that the bit failed due to heat. Any thoughts?

Larry

How deep the cut? Any burning on the wood? Did the cutting edges
fail or looked burned? Or did the bit shear off below the cutters?
Was it sharp?

Inquiring minds want to know.

-Zz

On 10/8/11 8:12 PM, Gramp's shop wrote:
The cuts was 5/16 deep. No burning on the wood. Cutting edges still look
good. Bit sheared off below the cutters. Factory sharp carbide with very
little use up to now.


I say again, bad bit. Those $5 woodcraft closeout bits are suspect to
begin with. Depends on the lot. From what I hear, they were having
issues with material later in production and may have switched suppliers
when they changed the name of their house brand to WoodRiver.

I still contend that 5/16" on a 1/4" bit is no sweat. With a high
quality bit, 5/16" *is* a shallow pass. Only taking 1/2 diameter (1/8")
is certainly safe, but also paranoid. Were your sucking out the sawdust?


--

-MIKE-

"Playing is not something I do at night, it's my function in life"
--Elvin Jones (1927-2004)
--
http://mikedrums.com

---remove "DOT" ^^^^ to reply

On Oct 9, 1:20*am, Leon lcb11211@swbelldotnet wrote:

Sounds like you might have been cutting too deep, especially in hard
maple. *I would have made it in 2 passes.

I cut everything In two passes, minimum. I rarely hog out the
material, _and_ finish the bottom, in the same pass.

On Oct 8, 5:05*pm, Gramp's shop wrote:
So there I was routing a 15" long 5/16 deep slot in some hard maple with
a 1/4 inch bit on a 1/2 inch shank and 12 inches into the cut the bit
sheared. *This bit was one of those green Woodcraft bits that they put
on sale from time to time. *I was using a pretty slow feed rate, but my
guess is that the bit failed due to heat. *Any thoughts?

Larry

Having worked with a few routers and bits over the last 40 years, a
5/16 deep pass, blind (aka dado) for a 1/4" bit is not very much.
BUT... to do such a cut properly, one should use an upcut spiral,
because no matter what your're cutting, with whatever kind of tool, it
is all about getting rid of the chips. The OP reported no burning, so
I can assume that there was a nice balance of cutting speed and feed
speed..and keeping in mind that Hard maple can be pretty damned
hard...BUT there was no burning and yet the bit broke.
The above information tells me the bit was defective/crap... but there
is another possibility. Gramp... did the bit scream? ( like a bit can
in hard maple)? I mean a high pitched scream? The bit could have been
oscillating from side to side, whilst still cutting and not burning..
just whipping. That would be a high frequency sonic/vibration event
that broke the bit. Where it broke would support that possibility.
Then again, I could be talking ****.

On Sat, 08 Oct 2011 20:19:57 -0500, -MIKE-
wrote:

On 10/8/11 8:12 PM, Gramp's shop wrote:
The cuts was 5/16 deep. No burning on the wood. Cutting edges still look
good. Bit sheared off below the cutters. Factory sharp carbide with very
little use up to now.


I say again, bad bit. Those $5 woodcraft closeout bits are suspect to
begin with. Depends on the lot. From what I hear, they were having
issues with material later in production and may have switched suppliers
when they changed the name of their house brand to WoodRiver.

I still contend that 5/16" on a 1/4" bit is no sweat. With a high
quality bit, 5/16" *is* a shallow pass. Only taking 1/2 diameter (1/8")
is certainly safe, but also paranoid. Were your sucking out the sawdust?

I agree, defective bit.

-Zz

On 10/8/11 9:21 PM, Robatoy wrote:
On Oct 8, 5:05 pm, Gramp's wrote:
So there I was routing a 15" long 5/16 deep slot in some hard maple with
a 1/4 inch bit on a 1/2 inch shank and 12 inches into the cut the bit
sheared. This bit was one of those green Woodcraft bits that they put
on sale from time to time. I was using a pretty slow feed rate, but my
guess is that the bit failed due to heat. Any thoughts?

Larry

Having worked with a few routers and bits over the last 40 years, a
5/16 deep pass, blind (aka dado) for a 1/4" bit is not very much.
BUT... to do such a cut properly, one should use an upcut spiral,
because no matter what your're cutting, with whatever kind of tool, it
is all about getting rid of the chips. The OP reported no burning, so
I can assume that there was a nice balance of cutting speed and feed
speed..and keeping in mind that Hard maple can be pretty damned
hard...BUT there was no burning and yet the bit broke.
The above information tells me the bit was defective/crap... but there
is another possibility. Gramp... did the bit scream? ( like a bit can
in hard maple)? I mean a high pitched scream? The bit could have been
oscillating from side to side, whilst still cutting and not burning..
just whipping. That would be a high frequency sonic/vibration event
that broke the bit. Where it broke would support that possibility.
Then again, I could be talking ****.

You're always talking ****. Even when it's good ****, it's still ****.
:-)


--

-MIKE-

"Playing is not something I do at night, it's my function in life"
--Elvin Jones (1927-2004)
--
http://mikedrums.com

---remove "DOT" ^^^^ to reply

On 10/8/2011 9:21 PM, Robatoy wrote:
On Oct 8, 5:05 pm, Gramp's wrote:
So there I was routing a 15" long 5/16 deep slot in some hard maple with
a 1/4 inch bit on a 1/2 inch shank and 12 inches into the cut the bit
sheared. This bit was one of those green Woodcraft bits that they put
on sale from time to time. I was using a pretty slow feed rate, but my
guess is that the bit failed due to heat. Any thoughts?

Larry

Having worked with a few routers and bits over the last 40 years, a
5/16 deep pass, blind (aka dado) for a 1/4" bit is not very much.
BUT... to do such a cut properly, one should use an upcut spiral,
because no matter what your're cutting, with whatever kind of tool, it
is all about getting rid of the chips. The OP reported no burning, so
I can assume that there was a nice balance of cutting speed and feed
speed..and keeping in mind that Hard maple can be pretty damned
hard...BUT there was no burning and yet the bit broke.
The above information tells me the bit was defective/crap... but there
is another possibility. Gramp... did the bit scream? ( like a bit can
in hard maple)? I mean a high pitched scream? The bit could have been
oscillating from side to side, whilst still cutting and not burning..
just whipping. That would be a high frequency sonic/vibration event
that broke the bit. Where it broke would support that possibility.
Then again, I could be talking ****.

Well, I wouldn't call it a scream, but the tonal pitch certainly changed
to a higher pitch. There was significant noise coming from me when I
discovered the sumbitch sheared and my old replacement bit was pretty
much close to dead. I bought a Bosch replacement at the big box, but I
do have an upcut bit that I hadn't considered using. I'll try it
tomorrow. Thanks!

On Oct 8, 10:49*pm, -MIKE- wrote:
On 10/8/11 9:21 PM, Robatoy wrote:









On Oct 8, 5:05 pm, Gramp's *wrote:
So there I was routing a 15" long 5/16 deep slot in some hard maple with
a 1/4 inch bit on a 1/2 inch shank and 12 inches into the cut the bit
sheared. *This bit was one of those green Woodcraft bits that they put
on sale from time to time. *I was using a pretty slow feed rate, but my
guess is that the bit failed due to heat. *Any thoughts?

Larry

Having worked with a few routers and bits over the last 40 years, a
5/16 deep pass, blind (aka dado) for a 1/4" bit is not very much.
BUT... to do such a cut properly, one should use an upcut spiral,
because no matter what your're cutting, with whatever kind of tool, it
is all about getting rid of the chips. The OP reported no burning, so
I can assume that there was a nice balance of cutting speed and feed
speed..and keeping in mind that Hard maple can be pretty damned
hard...BUT there was no burning and yet the bit broke.
The above information tells me the bit was defective/crap... but there
is another possibility. Gramp... did the bit scream? ( like a bit can
in hard maple)? I mean a high pitched scream? The bit could have been
oscillating from side to side, whilst still cutting and not burning..
just whipping. That would be a high frequency sonic/vibration event
that broke the bit. Where it broke would support that possibility.
Then again, I could be talking ****.

You're always talking ****. *Even when it's good ****, it's still ****.
* *:-)


Well I oughtta

Gramp's shop wrote:
So there I was routing a 15" long 5/16 deep slot in some hard maple
with a 1/4 inch bit on a 1/2 inch shank and 12 inches into the cut
the bit sheared. This bit was one of those green Woodcraft bits that
they put on sale from time to time. I was using a pretty slow feed
rate, but my guess is that the bit failed due to heat.

Any thoughts?

Buy a new bit.


--

dadiOH
____________________________

dadiOH's dandies v3.06...
....a help file of info about MP3s, recording from
LP/cassette and tips & tricks on this and that.
Get it at http://mysite.verizon.net/xico

Gramp's shop wrote:
On 10/8/2011 9:21 PM, Robatoy wrote:
On Oct 8, 5:05 pm, Gramp's wrote:
So there I was routing a 15" long 5/16 deep slot in some hard maple
with a 1/4 inch bit on a 1/2 inch shank and 12 inches into the cut
the bit sheared. This bit was one of those green Woodcraft bits
that they put on sale from time to time. I was using a pretty slow
feed rate, but my guess is that the bit failed due to heat. Any
thoughts? Larry

Having worked with a few routers and bits over the last 40 years, a
5/16 deep pass, blind (aka dado) for a 1/4" bit is not very much.
BUT... to do such a cut properly, one should use an upcut spiral,
because no matter what your're cutting, with whatever kind of tool,
it is all about getting rid of the chips. The OP reported no
burning, so I can assume that there was a nice balance of cutting
speed and feed speed..and keeping in mind that Hard maple can be
pretty damned hard...BUT there was no burning and yet the bit broke.
The above information tells me the bit was defective/crap... but
there is another possibility. Gramp... did the bit scream? ( like a
bit can in hard maple)? I mean a high pitched scream? The bit could
have been oscillating from side to side, whilst still cutting and
not burning.. just whipping. That would be a high frequency
sonic/vibration event that broke the bit. Where it broke would
support that possibility. Then again, I could be talking ****.

Well, I wouldn't call it a scream, but the tonal pitch certainly
changed to a higher pitch. There was significant noise coming from
me when I discovered the sumbitch sheared and my old replacement bit
was pretty much close to dead. I bought a Bosch replacement at the
big box, but I do have an upcut bit that I hadn't considered using. I'll
try it tomorrow. Thanks!

Lock it down tight. Those spiral bits can pull themselves out of the collet
and all of a sudden you are cutting deeper than you want.

--

dadiOH
____________________________

dadiOH's dandies v3.06...
....a help file of info about MP3s, recording from
LP/cassette and tips & tricks on this and that.
Get it at http://mysite.verizon.net/xico

In article , says...

Gramp's shop wrote:
On 10/8/2011 9:21 PM, Robatoy wrote:
On Oct 8, 5:05 pm, Gramp's wrote:
So there I was routing a 15" long 5/16 deep slot in some hard maple
with a 1/4 inch bit on a 1/2 inch shank and 12 inches into the cut
the bit sheared. This bit was one of those green Woodcraft bits
that they put on sale from time to time. I was using a pretty slow
feed rate, but my guess is that the bit failed due to heat. Any
thoughts? Larry

Having worked with a few routers and bits over the last 40 years, a
5/16 deep pass, blind (aka dado) for a 1/4" bit is not very much.
BUT... to do such a cut properly, one should use an upcut spiral,
because no matter what your're cutting, with whatever kind of tool,
it is all about getting rid of the chips. The OP reported no
burning, so I can assume that there was a nice balance of cutting
speed and feed speed..and keeping in mind that Hard maple can be
pretty damned hard...BUT there was no burning and yet the bit broke.
The above information tells me the bit was defective/crap... but
there is another possibility. Gramp... did the bit scream? ( like a
bit can in hard maple)? I mean a high pitched scream? The bit could
have been oscillating from side to side, whilst still cutting and
not burning.. just whipping. That would be a high frequency
sonic/vibration event that broke the bit. Where it broke would
support that possibility. Then again, I could be talking ****.

Well, I wouldn't call it a scream, but the tonal pitch certainly
changed to a higher pitch. There was significant noise coming from
me when I discovered the sumbitch sheared and my old replacement bit
was pretty much close to dead. I bought a Bosch replacement at the
big box, but I do have an upcut bit that I hadn't considered using. I'll
try it tomorrow. Thanks!

Lock it down tight. Those spiral bits can pull themselves out of the collet
and all of a sudden you are cutting deeper than you want.

Also, if possible use a featherboard. Usually when I break a bit it's
because I didn't have the work's movement solidly constrained.

On Sun, 9 Oct 2011 09:58:52 -0400, "dadiOH"
wrote:

Gramp's shop wrote:
So there I was routing a 15" long 5/16 deep slot in some hard maple
with a 1/4 inch bit on a 1/2 inch shank and 12 inches into the cut
the bit sheared. This bit was one of those green Woodcraft bits that
they put on sale from time to time. I was using a pretty slow feed
rate, but my guess is that the bit failed due to heat.

Any thoughts?

Buy a new bit.

New bit, shallower cuts, and time to let the bit cool between passes.
The smaller the bit, the more quickly they overheat. DAMHIKT

--
Never trouble another for what you can do for yourself.
-- Thomas Jefferson

"dadiOH" wrote in message
...
Gramp's shop wrote:
On 10/8/2011 9:21 PM, Robatoy wrote:
On Oct 8, 5:05 pm, Gramp's wrote:
So there I was routing a 15" long 5/16 deep slot in some hard maple
with a 1/4 inch bit on a 1/2 inch shank and 12 inches into the cut
the bit sheared. This bit was one of those green Woodcraft bits
that they put on sale from time to time. I was using a pretty slow
feed rate, but my guess is that the bit failed due to heat. Any
thoughts? Larry

Having worked with a few routers and bits over the last 40 years, a
5/16 deep pass, blind (aka dado) for a 1/4" bit is not very much.
BUT... to do such a cut properly, one should use an upcut spiral,
because no matter what your're cutting, with whatever kind of tool,
it is all about getting rid of the chips. The OP reported no
burning, so I can assume that there was a nice balance of cutting
speed and feed speed..and keeping in mind that Hard maple can be
pretty damned hard...BUT there was no burning and yet the bit broke.
The above information tells me the bit was defective/crap... but
there is another possibility. Gramp... did the bit scream? ( like a
bit can in hard maple)? I mean a high pitched scream? The bit could
have been oscillating from side to side, whilst still cutting and
not burning.. just whipping. That would be a high frequency
sonic/vibration event that broke the bit. Where it broke would
support that possibility. Then again, I could be talking ****.

Well, I wouldn't call it a scream, but the tonal pitch certainly
changed to a higher pitch. There was significant noise coming from
me when I discovered the sumbitch sheared and my old replacement bit
was pretty much close to dead. I bought a Bosch replacement at the
big box, but I do have an upcut bit that I hadn't considered using. I'll
try it tomorrow. Thanks!

Lock it down tight. Those spiral bits can pull themselves out of the
collet and all of a sudden you are cutting deeper than you want.

Also clean the bit shank and the inside of the collet with a little lacquer
thinner, this will remove any oil film that can cause a bit to move out of
the collet.

I have had a couple of 1/4 inch shank bits fail on me. They were cheap bits
bought as a set from Canadian Tire, a source of cheap tools in Canada. I
have learned to never push them, even a little.

On Oct 9, 11:43*am, "EXT" wrote:
"dadiOH" wrote in message

...









Gramp's shop wrote:
On 10/8/2011 9:21 PM, Robatoy wrote:
On Oct 8, 5:05 pm, Gramp's *wrote:
So there I was routing a 15" long 5/16 deep slot in some hard maple
with a 1/4 inch bit on a 1/2 inch shank and 12 inches into the cut
the bit sheared. *This bit was one of those green Woodcraft bits
that they put on sale from time to time. *I was using a pretty slow
feed rate, but my guess is that the bit failed due to heat. *Any
thoughts? Larry

Having worked with a few routers and bits over the last 40 years, a
5/16 deep pass, blind (aka dado) for a 1/4" bit is not very much.
BUT... to do such a cut properly, one should use an upcut spiral,
because no matter what your're cutting, with whatever kind of tool,
it is all about getting rid of the chips. The OP reported no
burning, so I can assume that there was a nice balance of cutting
speed and feed speed..and keeping in mind that Hard maple can be
pretty damned hard...BUT there was no burning and yet the bit broke.
The above information tells me the bit was defective/crap... but
there is another possibility. Gramp... did the bit scream? ( like a
bit can in hard maple)? I mean a high pitched scream? The bit could
have been oscillating from side to side, whilst still cutting and
not burning.. just whipping. That would be a high frequency
sonic/vibration event that broke the bit. Where it broke would
support that possibility. Then again, I could be talking ****.

Well, I wouldn't call it a scream, but the tonal pitch certainly
changed to a higher pitch. *There was significant noise coming from
me when I discovered the sumbitch sheared and my old replacement bit
was pretty much close to dead. *I bought a Bosch replacement at the
big box, but I do have an upcut bit that I hadn't considered using. I'll
try it tomorrow. *Thanks!

Lock it down tight. *Those spiral bits can pull themselves out of the
collet and all of a sudden you are cutting deeper than you want.

Also clean the bit shank and the inside of the collet with a little lacquer
thinner, this will remove any oil film that can cause a bit to move out of
the collet.

I have had a couple of 1/4 inch shank bits fail on me. They were cheap bits
bought as a set from Canadian Tire, a source of cheap tools in Canada. I
have learned to never push them, even a little.

Good advice.

In ,
Gramp's shop typed:
So there I was routing a 15" long 5/16 deep slot in some
hard maple with a 1/4 inch bit on a 1/2 inch shank and 12
inches into the cut the bit sheared. This bit was one of
those green Woodcraft bits that they put on sale from
time to time. I was using a pretty slow feed rate, but
my guess is that the bit failed due to heat. Any
thoughts?
Larry

Well, from what I can see, the overheating ate the bit hardness and hitting
that second knot in the wood at that unreasonably high speed I saw you
using, was the cause. Oh, and since you bottomrf out the bit, you diidn't
get a perfect alignment either; it was wobbling just befors t broke. But
that's all I could see from here.

On Oct 8, 8:20*pm, Leon lcb11211@swbelldotnet wrote:
On 10/8/2011 4:05 PM, Gramp's shop wrote:

So there I was routing a 15" long 5/16 deep slot in some hard maple with
a 1/4 inch bit on a 1/2 inch shank and 12 inches into the cut the bit
sheared. This bit was one of those green Woodcraft bits that they put on
sale from time to time. I was using a pretty slow feed rate, but my
guess is that the bit failed due to heat. Any thoughts?

Larry

Sounds like you might have been cutting too deep, especially in hard
maple. *I would have made it in 2 passes.

If the finish quality matters at all, always in more than
one pass. Single pass in maple guarantees scorching.