Used a De Walt 3326 140T blade in a circular saw as I wanted a clean
cut and the blade was new. Was I EVER wrong! Got about 3" into a cut
in 3/4" multiply slab and the blade bound. Extracted the blade and
second through fourth were equally exciting. Let the smoke clear and
double checked alignment of blade with guide as blade was drifting
away from the guide while smoking, not sure what it was using but it
smoked! Next cut I just slowed down feed rate but no resolve. Could
NOT extract the blade and saw from ply. Dismounted the saw from the
blade, wedged the saw kerf and got the blade out with difficulty.
Switched to the old 24T blade and made clean cuts.

I do NOT understand what was going wrong but obviously something was
out of whack! Guess I'll reserve that blade for thin ply cuts only.
Observations welcomed.

wrote:
Used a De Walt 3326 140T blade in a circular saw as I wanted a clean
cut and the blade was new. Was I EVER wrong! Got about 3" into a cut
in 3/4" multiply slab and the blade bound. Extracted the blade and
second through fourth were equally exciting. Let the smoke clear and
double checked alignment of blade with guide as blade was drifting
away from the guide while smoking, not sure what it was using but it
smoked! Next cut I just slowed down feed rate but no resolve. Could
NOT extract the blade and saw from ply. Dismounted the saw from the
blade, wedged the saw kerf and got the blade out with difficulty.
Switched to the old 24T blade and made clean cuts.

I do NOT understand what was going wrong but obviously something was
out of whack! Guess I'll reserve that blade for thin ply cuts only.
Observations welcomed.

That blade appears to be hollow ground. If so you probably had it set
too low and the fatter part near the arbor was binding in the kerf.
Hollow ground blades especially need to be set so that the teeth just
protrude through the material being cut.

Let us know.

wrote in message
...
Used a De Walt 3326 140T blade in a circular saw as I wanted a clean
cut and the blade was new. Was I EVER wrong! Got about 3" into a cut
in 3/4" multiply slab and the blade bound. Extracted the blade and
second through fourth were equally exciting. Let the smoke clear and
double checked alignment of blade with guide as blade was drifting
away from the guide while smoking, not sure what it was using but it
smoked! Next cut I just slowed down feed rate but no resolve. Could
NOT extract the blade and saw from ply. Dismounted the saw from the
blade, wedged the saw kerf and got the blade out with difficulty.
Switched to the old 24T blade and made clean cuts.

I do NOT understand what was going wrong but obviously something was
out of whack! Guess I'll reserve that blade for thin ply cuts only.
Observations welcomed.

Ray has hit on a possibility. Additionally most likely your 24 tooth blade
is a carbide tipped blade. If this is true, a carbide blade leaves a kerf
that is wider than the body of the blade. Most plywood blades have no
carbide tips and the teeth have little to no set. The teeth cut little if
no wider than the body of the blade. When the body of the blade comes in
contact with the wood you get the results that you are having.

I was gonna mention, and I'm sure this ain't the right place, that I set my
200 tooth ply blade backward to cut acrylic light shield, and immediately
breezed through 2" ABS with perfect joints!



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wrote:
Used a De Walt 3326 140T blade in a circular saw as I wanted a clean
cut and the blade was new. Was I EVER wrong! Got about 3" into a cut
in 3/4" multiply slab and the blade bound. Extracted the blade and
second through fourth were equally exciting. Let the smoke clear and
double checked alignment of blade with guide as blade was drifting
away from the guide while smoking, not sure what it was using but it
smoked! Next cut I just slowed down feed rate but no resolve. Could
NOT extract the blade and saw from ply. Dismounted the saw from the
blade, wedged the saw kerf and got the blade out with difficulty.
Switched to the old 24T blade and made clean cuts.

I do NOT understand what was going wrong but obviously something was
out of whack! Guess I'll reserve that blade for thin ply cuts only.
Observations welcomed.

A couple of things I would suspect off the bat. First, cutting plywood
with a steel blade that has 140 teeth. If you are not great (not just
good) at cutting a straight line with a circular saw, this blade will
be your undoing in 3/4" material. There is not enough clearance on the
set of the teeth to allow for any wobble at all. You must use a long,
straight guide of some sort for your rips, or you will do what you have
done, and that is burn the blade. When you correct a tiny bit (just a
tiny bit with a 140 tooth blade) to get back on your line, you throw
the blade out of alignment, which causes the blade to rub instead of
cut, making heat. Heat causes the blade to distort, making more
rubbing action, and then finally a literal burning of wood. Since you
are using a steel blade and you got it that hot, you have probably
ruined that blade.

So you can guess the second. IMO, the 140T isn't a good choice in a
circular saw. Too many teeth in contact at once with the material
making it very unforgiving when sawing. They are OK at best for 1/4"
ply, but no more. And with the resin glues that are used in today's
plywoods, all those teeth making all that heat is a recipe for
disaster.

OTOH, my experience with DeWalt blades hasn't been good either. They
get the "close but no cigar" nod from me. Also, I am taking for
granted that you are using a saw that has plenty of power for ripping.


When set up on a job that I need to knock out a quick cabinet, shelves,
or anything that requires ripping sheet goods with my circ saw +
guide, this is what is in my saw:

http://tinyurl.com/y8we3q

Been using these blades for years and have changed all of mine over to
them for finish work. When I use a guide, I have seen cuts as smooth
as most table saws. Now all my 16 - 24 tooth consumable blades that I
buy on sale I use for framing, demo, etc.

Robert

wrote:
Used a De Walt 3326 140T blade in a circular saw as I wanted a clean
cut and the blade was new. Was I EVER wrong! Got about 3" into a cut
in 3/4" multiply slab and the blade bound. Extracted the blade and
second through fourth were equally exciting. Let the smoke clear and
double checked alignment of blade with guide as blade was drifting
away from the guide while smoking, not sure what it was using but it
smoked! Next cut I just slowed down feed rate but no resolve. Could
NOT extract the blade and saw from ply. Dismounted the saw from the
blade, wedged the saw kerf and got the blade out with difficulty.
Switched to the old 24T blade and made clean cuts.

I do NOT understand what was going wrong but obviously something was
out of whack! Guess I'll reserve that blade for thin ply cuts only.
Observations welcomed.

Those 140T hollow-ground blades are better used for plastics or really
thin materials. For 3/4" wood, I'd use a 40T carbide-tipped finish
blade, like the Freud D0740X (available at Home Depot, if I remember
right):

http://www.freud-tools.com/freuddiabfin.html

Also, using a saw guide is an immense help to get straight cuts with
circular saws:
http://benchnotes.com/Skillsaw%20Gui..._guide_boa.htm
or
http://www.woodzone.com/tips/saw_guide.htm

Regards,

Mark

Thanks for the comments/observations! Teeth were barely exiting the
ply. Labeled for ply. Had to use pliers to handle so it's dust,
burned dust at that. The 24T Piranha finished the job nicely and will
continue to be used. Using the Penn State Panel Cutting jig as guide.

On 8 Jan 2007 05:52:27 -0800, "RayV" wrote:


wrote:
Used a De Walt 3326 140T blade in a circular saw as I wanted a clean
cut and the blade was new. Was I EVER wrong! Got about 3" into a cut
in 3/4" multiply slab and the blade bound. Extracted the blade and
second through fourth were equally exciting. Let the smoke clear and
double checked alignment of blade with guide as blade was drifting
away from the guide while smoking, not sure what it was using but it
smoked! Next cut I just slowed down feed rate but no resolve. Could
NOT extract the blade and saw from ply. Dismounted the saw from the
blade, wedged the saw kerf and got the blade out with difficulty.
Switched to the old 24T blade and made clean cuts.

I do NOT understand what was going wrong but obviously something was
out of whack! Guess I'll reserve that blade for thin ply cuts only.
Observations welcomed.

That blade appears to be hollow ground. If so you probably had it set
too low and the fatter part near the arbor was binding in the kerf.
Hollow ground blades especially need to be set so that the teeth just
protrude through the material being cut.

Let us know.

On Mon, 08 Jan 2007 08:18:14 -0500, wrote:

Used a De Walt 3326 140T blade in a circular saw as I wanted a clean
cut and the blade was new. Was I EVER wrong! Got about 3" into a cut
in 3/4" multiply slab and the blade bound. Extracted the blade and
second through fourth were equally exciting. Let the smoke clear and
double checked alignment of blade with guide as blade was drifting
away from the guide while smoking, not sure what it was using but it
smoked! Next cut I just slowed down feed rate but no resolve. Could
NOT extract the blade and saw from ply. Dismounted the saw from the
blade, wedged the saw kerf and got the blade out with difficulty.
Switched to the old 24T blade and made clean cuts.

I do NOT understand what was going wrong but obviously something was
out of whack! Guess I'll reserve that blade for thin ply cuts only.
Observations welcomed.

Am I reading this right, 140 tooth?

That's an awful lot of teeth on a circular saw... The only time I've
used a blade like that was for cutting wood panelling- which is very
thin.

Freud makes a 40 tooth blade for fine cutting that works really nice
on plywood, especially if you add a "zero clearance" hardboard foot to
the bottom of the saw to prevent chipping.

But 140 teeth can't have much of a gullet at all- my guess would be
that instead of tossing the sawdust out effectively, it is clogging
and burning before it gets through that 3/4" plywood. Save that blade
for panelling or cutting things like plexiglass.

wrote:
Thanks for the comments/observations! Teeth were barely exiting the
ply. Labeled for ply. Had to use pliers to handle so it's dust,
burned dust at that. The 24T Piranha finished the job nicely and will
continue to be used. Using the Penn State Panel Cutting jig as guide.


I have the Piranaha in my saw and rarely take it out. Cuts
surprisingly well and is cheap. I have no reason to try any other
blade.

Prometheus wrote:

Freud makes a 40 tooth blade for fine cutting that works really nice
on plywood, especially if you add a "zero clearance" hardboard foot to
the bottom of the saw to prevent chipping.

I might try that out ... what would be a good way to attach the
hardboard to the saw's shoe?

Thanks in advance,

Mark

redbelly wrote:
Prometheus wrote:

Freud makes a 40 tooth blade for fine cutting that works really nice
on plywood, especially if you add a "zero clearance" hardboard foot to
the bottom of the saw to prevent chipping.

I might try that out ... what would be a good way to attach the
hardboard to the saw's shoe?

Thanks in advance,

Double sided carpet tape always works for me. If you like it, you can
make all permanenent with countersunk flat head machine screws.

Polyu glue also works but difficult to reverse. Like double sided
tape idea, thanks.

On Tue, 09 Jan 2007 11:36:59 -0500, B A R R Y
wrote:

redbelly wrote:
Prometheus wrote:

Freud makes a 40 tooth blade for fine cutting that works really nice
on plywood, especially if you add a "zero clearance" hardboard foot to
the bottom of the saw to prevent chipping.

I might try that out ... what would be a good way to attach the
hardboard to the saw's shoe?

Thanks in advance,

Double sided carpet tape always works for me. If you like it, you can
make all permanenent with countersunk flat head machine screws.

wrote:
Polyu glue also works but difficult to reverse. Like double sided
tape idea, thanks.

All wood shops should have a roll on hand at all times. G

B A R R Y wrote:
redbelly wrote:
Prometheus wrote:

Freud makes a 40 tooth blade for fine cutting that works really nice
on plywood, especially if you add a "zero clearance" hardboard foot to
the bottom of the saw to prevent chipping.

I might try that out ... what would be a good way to attach the
hardboard to the saw's shoe?

Thanks in advance,

Double sided carpet tape always works for me. If you like it, you can
make all permanenent with countersunk flat head machine screws.

Barry, thanks. -- Mark

On 9 Jan 2007 06:51:28 -0800, "redbelly" wrote:

Prometheus wrote:

Freud makes a 40 tooth blade for fine cutting that works really nice
on plywood, especially if you add a "zero clearance" hardboard foot to
the bottom of the saw to prevent chipping.

I might try that out ... what would be a good way to attach the
hardboard to the saw's shoe?

In my case, I countersunk the holes in the hardboard and drilled and
tapped a few holes in the shoe. If you don't want to go to that
amount of trouble before you try it out, double-sided tape might work
in a pinch, especially if you have a smooth shoe, and not one with the
sawdust grooves in it.

Make sure that if you go with the drill and tap method, you make those
countersinks deep enough that you don't scratch up the wood with the
bolt heads.

Prometheus wrote:
On 9 Jan 2007 06:51:28 -0800, "redbelly" wrote:

Prometheus wrote:

Freud makes a 40 tooth blade for fine cutting that works really nice
on plywood, especially if you add a "zero clearance" hardboard foot to
the bottom of the saw to prevent chipping.

I might try that out ... what would be a good way to attach the
hardboard to the saw's shoe?

In my case, I countersunk the holes in the hardboard and drilled and
tapped a few holes in the shoe. If you don't want to go to that
amount of trouble before you try it out, double-sided tape might work
in a pinch, especially if you have a smooth shoe, and not one with the
sawdust grooves in it.

Make sure that if you go with the drill and tap method, you make those
countersinks deep enough that you don't scratch up the wood with the
bolt heads.

Thanks. I THINK I have a 10-32 tap in my set, if not then I'd probably
go with 8-32.

At this point it's a low priority "something to try one of these days"
item, but thank you for replying.

Mark