.... actually past the breaking point.

1/4" straight carbide bit (Craftsman), kinda long (more than 3/4"),
being used to cut a slot in 3/4" pine, using my old Craftsman router
(1/4", old-fashioned little one). I was cutting along, carefully
regulating the feed rate so as to only slow down the motor a little bit,
thinking how much stress that bit was taking. Sure 'nuff, after cutting
about 6-7 slots about 15" long, the bit just broke off. Didn't go flying
at all, but just landed on the table under the router in a pile of wood
chips.

So obviously this is my bad. I was even thinking as I was making that
last cut that maybe I should be doing this in two passes.

So what're the rules of thumb for how much stress is too much for bits
like these? The bit seems well-made, so I don't think I can blame it.
Now I'm thinking of making that same cut in two passes (~3/8" depth of
cut each). Would that be un-stressful enough for the bit?


--
Save the Planet
Kill Yourself

- motto of the Church of Euthanasia (http://www.churchofeuthanasia.org/)

Subject

It's a "finishing", not a "hogging" tool.

Plan accordingly.

Lew

"David Nebenzahl" wrote in message
.com...
... actually past the breaking point.

1/4" straight carbide bit (Craftsman), kinda long (more than 3/4"), being
used to cut a slot in 3/4" pine, using my old Craftsman router (1/4",
old-fashioned little one). I was cutting along, carefully regulating the
feed rate so as to only slow down the motor a little bit, thinking how
much stress that bit was taking. Sure 'nuff, after cutting about 6-7 slots
about 15" long, the bit just broke off. Didn't go flying at all, but just
landed on the table under the router in a pile of wood chips.

So obviously this is my bad. I was even thinking as I was making that last
cut that maybe I should be doing this in two passes.

So what're the rules of thumb for how much stress is too much for bits
like these? The bit seems well-made, so I don't think I can blame it. Now
I'm thinking of making that same cut in two passes (~3/8" depth of cut
each). Would that be un-stressful enough for the bit?


--
Save the Planet
Kill Yourself

- motto of the Church of Euthanasia (http://www.churchofeuthanasia.org/)

with straight cutters, I don't cut deeper than the width of the cutter in
any single pass.

your opinions will probably vary (yowpv?)

jc

David Nebenzahl wrote:
.... actually past the breaking point.

1/4" straight carbide bit (Craftsman), kinda long (more than 3/4"),
being used to cut a slot in 3/4" pine, using my old Craftsman router
(1/4", old-fashioned little one). I was cutting along, carefully
regulating the feed rate so as to only slow down the motor a little bit,
thinking how much stress that bit was taking. Sure 'nuff, after cutting
about 6-7 slots about 15" long, the bit just broke off. Didn't go flying
at all, but just landed on the table under the router in a pile of wood
chips.

So obviously this is my bad. I was even thinking as I was making that
last cut that maybe I should be doing this in two passes.

So what're the rules of thumb for how much stress is too much for bits
like these? The bit seems well-made, so I don't think I can blame it.
Now I'm thinking of making that same cut in two passes (~3/8" depth of
cut each). Would that be un-stressful enough for the bit?



A general rule of thumb is to cut only as deep as the diameter of the
router bit. For a 1/4" diameter bit the maximum depth os a single pass
would be 1/4" cut.

--
Jack Novak
Buffalo, NY - USA

On May 10, 7:20*pm, "Lew Hodgett" wrote:
Subject

It's a "finishing", not a "hogging" tool.

Plan accordingly.

Lew

Indeed. Wrong bit for the job.
That is more a job for an 'upcut' spiral. I find that one can lean
into those a lot more as it is all about chip-ejection.
A straight bit can't get out of its own way because the chips have
nowhere to go but towards the back of the cut.

On May 10, 7:32*pm, Nova wrote:

A general rule of thumb is to cut only as deep as the diameter of the
router bit. *For a 1/4" diameter bit the maximum depth os a single pass
would be 1/4" cut.

I'd add another thumb to your rule, and not cut deeper than the
smaller of the bit or shank diameter.

R

On 5/10/2009 5:04 PM Dave Balderstone spake thus:

In article , David
Nebenzahl wrote:

So what're the rules of thumb for how much stress is too much for bits
like these? The bit seems well-made, so I don't think I can blame it.
Now I'm thinking of making that same cut in two passes (~3/8" depth of
cut each). Would that be un-stressful enough for the bit?

With a straight cut bit I don't go more than 1/8" per pass.

Take more, shallower, cuts, and the job will go faster because you
won't be fighting the tool.

Good suggestions so far, including the one about using a different tool
(spiral cutter).

I notice one thing that happens is that there's a lot of fairly
high-frequency chatter when you use a tool like this to "hog" wood, less
with shallower cuts. It doesn't show so much on the cut, but I can sure
hear it. I wouldn't be surprised if this vibration contributes to early
tool mortality (all that flexing and stuff).


--
Save the Planet
Kill Yourself

- motto of the Church of Euthanasia (http://www.churchofeuthanasia.org/)

On Sun, 10 May 2009 18:24:29 -0700, David Nebenzahl
wrote:

I notice one thing that happens is that there's a lot of fairly
high-frequency chatter when you use a tool like this to "hog" wood, less
with shallower cuts. It doesn't show so much on the cut, but I can sure
hear it. I wouldn't be surprised if this vibration contributes to early
tool mortality (all that flexing and stuff).


I'm sure you're correct with that observation. Things don't vibrate
without flexing and stress reversals from those cyclic deflections are
prime contributors to fatigue cracking and failure.

Tom Veatch
Wichita, KS
USA

An armed society is a polite society.
Manners are good when one may have to back up his acts with his life.
Robert A. Heinlein

On Sun, 10 May 2009 20:01:38 -0600, Dave Balderstone
wrote:

In other words, the hurrier I go, the behinder I get.

I've made more scrap as a result of impatience than from all other
causes combined.

Tom Veatch
Wichita, KS
USA

An armed society is a polite society.
Manners are good when one may have to back up his acts with his life.
Robert A. Heinlein

Tom Veatch wrote:

I've made more scrap as a result of impatience than from all other
causes combined.
====================================
It wasn't until I started sailing single handed that I began to truly
understand the virtue of patience.

A boat under sail has a rhythm that is insync with nature.

Try to rush things, you WILL make a mistake.

Make a mistake when single handing, chances are pretty good you
ultimately end up DEAD.

Chances of finding any remains, SLIM and NONE, more likely NONE.

You quickly learn to be patient.

I find it is also a pleasant way to enjoy life while sailing.

YMMV.

Lew

"David Nebenzahl" wrote in message
.com...
On 5/10/2009 5:04 PM Dave Balderstone spake thus:

In article , David
Nebenzahl wrote:

So what're the rules of thumb for how much stress is too much for bits
like these? The bit seems well-made, so I don't think I can blame it.
Now I'm thinking of making that same cut in two passes (~3/8" depth of
cut each). Would that be un-stressful enough for the bit?

With a straight cut bit I don't go more than 1/8" per pass.

Take more, shallower, cuts, and the job will go faster because you
won't be fighting the tool.

Good suggestions so far, including the one about using a different tool
(spiral cutter).

I notice one thing that happens is that there's a lot of fairly
high-frequency chatter when you use a tool like this to "hog" wood, less
with shallower cuts. It doesn't show so much on the cut, but I can sure
hear it. I wouldn't be surprised if this vibration contributes to early
tool mortality (all that flexing and stuff).


--
the suggestion about the upcut bit is a good one because of the chip
clearing. However, by taking much lighter passes with a straight bit, you
may find that the chip clearing becomes moot. lighter passes produce less
chips which are less likely to get jammed in a shallower grove. In other
words, they become self clearing. And straight bits are cheaper!

"Lew Hodgett" wrote in message
...

It wasn't until I started sailing single handed that I began to truly
understand the virtue of patience.

A boat under sail has a rhythm that is insync with nature.

Try to rush things, you WILL make a mistake.

Make a mistake when single handing, chances are pretty good you ultimately
end up DEAD.

Chances of finding any remains, SLIM and NONE, more likely NONE.

You quickly learn to be patient.

I find it is also a pleasant way to enjoy life while sailing.

YMMV.

Lew

Lew,

It's hard to be patient when you are falling off the backsides of waves in a
10 foot sea at 2AM.

You had better be patient though. :-)

Lew Hodgett wrote:
Tom Veatch wrote:

I've made more scrap as a result of impatience than from all other
causes combined.
====================================
It wasn't until I started sailing single handed that I began to truly
understand the virtue of patience.

A boat under sail has a rhythm that is insync with nature.

Try to rush things, you WILL make a mistake.

Make a mistake when single handing, chances are pretty good you
ultimately end up DEAD.

Chances of finding any remains, SLIM and NONE, more likely NONE.

You quickly learn to be patient.

I find it is also a pleasant way to enjoy life while sailing.

YMMV.

Lew




I always thought that the ability to plan the future and patience were
the things that differentiated a sailor from the common man.

"Keith Nuttle" wrote in message
...
Lew Hodgett wrote:




I always thought that the ability to plan the future and patience were the
things that differentiated a sailor from the common man.

That may be the description for an aged sailor, but in their youth, it also
has to do with proving they have hair on their chest.

"David Nebenzahl" wrote in message
.com...
... actually past the breaking point.

1/4" straight carbide bit (Craftsman), kinda long (more than 3/4"), being
used to cut a slot in 3/4" pine, using my old Craftsman router (1/4",
old-fashioned little one). I was cutting along, carefully regulating the
feed rate so as to only slow down the motor a little bit, thinking how
much stress that bit was taking. Sure 'nuff, after cutting about 6-7 slots
about 15" long, the bit just broke off. Didn't go flying at all, but just
landed on the table under the router in a pile of wood chips.

So obviously this is my bad. I was even thinking as I was making that last
cut that maybe I should be doing this in two passes.

So what're the rules of thumb for how much stress is too much for bits
like these? The bit seems well-made, so I don't think I can blame it. Now
I'm thinking of making that same cut in two passes (~3/8" depth of cut
each). Would that be un-stressful enough for the bit?


--
Save the Planet
Kill Yourself

- motto of the Church of Euthanasia (http://www.churchofeuthanasia.org/)

If your bit was solid carbide you were using the wrong bit, I have found
that solid carbide bits tend to break/shatter when you get vibration, over
torque on bit or heat build up. The bits are too brittle to handle much
stress. Craftsman sometimes seems to have bits with case hardened shafts
which act like solid carbide bits and break easily, any stress on the bit
and you have a two piece bit. To do what you were doing I would use a HSS
bit which seems to take stress better then carbide bits or bits with carbide
cutters. You will change bits often though. Your best bet is as stated in
other post is to use multiple cuts to reduce stress on the bit. If you wish
to make only one router cut you could hog out the slot with a drill bit and
use the router for clean up but I still believe that a decent quality bit
with carbide cutters and multiple cuts would be the best way to go.

"Lowell Holmes" wrote:

Lew,

It's hard to be patient when you are falling off the backsides of
waves in a 10 foot sea at 2AM.

You had better be patient though. :-)

I hear ya, but I'm of the school that gentlemen don't go to weather,
that's part of being patient.grin

Lew

"Lew Hodgett" wrote in message
...
"Lowell Holmes" wrote:

Lew,

It's hard to be patient when you are falling off the backsides of waves
in a 10 foot sea at 2AM.

You had better be patient though. :-)

I hear ya, but I'm of the school that gentlemen don't go to weather,
that's part of being patient.grin

Lew

I agree, but sometimes it just seems necessary to "harden up" and in those
instances, my adam's apple would be in my mouth.

"Lowell Holmes" wrote:

I agree, but sometimes it just seems necessary to "harden up" and in
those instances, my adam's apple would be in my mouth.

Being a "cruiser" rather than a "racer", I get "there" when I get
"there", as the saying goes.

The party can wait or not, makes no difference.

Lew

"David Nebenzahl" wrote in message
.com...
... actually past the breaking point.

1/4" straight carbide bit (Craftsman), kinda long (more than 3/4"), being
used to cut a slot in 3/4" pine, using my old Craftsman router (1/4",
old-fashioned little one). I was cutting along, carefully regulating the
feed rate so as to only slow down the motor a little bit, thinking how
much stress that bit was taking. Sure 'nuff, after cutting about 6-7 slots
about 15" long, the bit just broke off. Didn't go flying at all, but just
landed on the table under the router in a pile of wood chips.

So obviously this is my bad. I was even thinking as I was making that last
cut that maybe I should be doing this in two passes.

So what're the rules of thumb for how much stress is too much for bits
like these? The bit seems well-made, so I don't think I can blame it. Now
I'm thinking of making that same cut in two passes (~3/8" depth of cut
each). Would that be un-stressful enough for the bit?


I have found that end mill bits work well, last much longer, and are less
expensive.

On 5/11/2009 6:49 AM sweet sawdust spake thus:

"David Nebenzahl" wrote in message
.com...

... actually past the breaking point.

1/4" straight carbide bit (Craftsman), kinda long (more than 3/4"), being
used to cut a slot in 3/4" pine, using my old Craftsman router (1/4",
old-fashioned little one). I was cutting along, carefully regulating the
feed rate so as to only slow down the motor a little bit, thinking how
much stress that bit was taking. Sure 'nuff, after cutting about 6-7 slots
about 15" long, the bit just broke off. Didn't go flying at all, but just
landed on the table under the router in a pile of wood chips.

If your bit was solid carbide you were using the wrong bit, I have found
that solid carbide bits tend to break/shatter when you get vibration, over
torque on bit or heat build up. The bits are too brittle to handle much
stress.

Not a solid carbide bit, but a seemingly well-made standard (brazed?)
bit with steel shank.


--
Found--the gene that causes belief in genetic determinism

"David Nebenzahl" wrote in message
.com...
On 5/11/2009 6:49 AM sweet sawdust spake thus:

"David Nebenzahl" wrote in message
.com...

... actually past the breaking point.

1/4" straight carbide bit (Craftsman), kinda long (more than 3/4"),
being used to cut a slot in 3/4" pine, using my old Craftsman router
(1/4", old-fashioned little one). I was cutting along, carefully
regulating the feed rate so as to only slow down the motor a little bit,
thinking how much stress that bit was taking. Sure 'nuff, after cutting
about 6-7 slots about 15" long, the bit just broke off. Didn't go flying
at all, but just landed on the table under the router in a pile of wood
chips.

If your bit was solid carbide you were using the wrong bit, I have found
that solid carbide bits tend to break/shatter when you get vibration,
over torque on bit or heat build up. The bits are too brittle to handle
much stress.

Not a solid carbide bit, but a seemingly well-made standard (brazed?) bit
with steel shank.


--
Found--the gene that causes belief in genetic determinism

Solid Carbide bits are wonderful when they work and well worth the money,
but when they get stressed they aren't worth a dime. I have never dulled
one but have broken several and the ones I have left just set in their
boxes. I know that craftsman does not always get the best in a lot of items
and their router bits seem to be/have been one of the areas of concern. Of
course like Harbor Freight its hard to say what they will have in quality
from day to day. With a good bit properly made you should be able to make
the cut you were describing with out problems. However if anything goes
wrong your are in trouble, and it sounded like something went "wrong" and
will probably never be able to figure out what it was nor will anyone else
and it will probably never occur again, the same way anyway. That is why the
multiple cuts for each slot, if something goes wrong it is usually so minor
that you never notice it, where as in a deep cut the same problem will be
devestating, as you noticed.

It sounds like you are cutting free hand with the router rather then using a
table, this can make slot cutting tricky, You might try making a slot
cutting jig for the job. it will give you much better repeatability and
accuracy especially when making multiple cuts needed to do a deep slot.
Good Luck and have fun

On 5/11/2009 12:11 PM sweet sawdust spake thus:

It sounds like you are cutting free hand with the router rather then
using a table, this can make slot cutting tricky, You might try
making a slot cutting jig for the job. it will give you much better
repeatability and accuracy especially when making multiple cuts
needed to do a deep slot.

Nope, using my trusty old homemade router table. Makes great cuts with
reliable repeatability. (I'd never attempt anything like this "freehand".)

I was just pushing the bit beyond its limits was the thing.


--
Found--the gene that causes belief in genetic determinism

On May 10, 5:54*pm, David Nebenzahl wrote:
... actually past the breaking point.

1/4" straight carbide bit (Craftsman), kinda long (more than 3/4"),
I was using a 1/2" diameter carbide bit to cut some 7/16" OSB. While
it did not break off, there was quite a bit of smokin going on.

I went to Lowes and found a similar bit with three flutes and thought
that might have helped.

I needed the bearing on the bottom of the bit so a spiral up/down bit
would not have helped.

But a 1/2" diameter shank bit would likely do better than a 1/4"

I was cutting out the waste siding for a window opening. For the
second window, I used a jig saw to rough cut then trimmed it up with
the router bit.

Like the man said, it for trimming, not hogging out!