Why do rip blades rip faster? They have fewer teeth than combination
or general purpose blades, so the resulting gullets are larger. But I
don't see most people feeding their stock that fast. So it doesn't
seem like waste removal via the large gullets can be that big a plus.
I would normally think that more teeth would = more cutting would =
faster cutting.
Anyone have any good links to articles about blades and tooth angles
and such?
Oh, and if a rip blade rips faster, will it also cross-cut faster?
Ignoring quality of cut, of course.
On 29 Jan, 05:37, [email protected] wrote:
> Why do rip blades rip faster?
Because they're ripping and not cutting. Find a copy of Hoadley and
read the chapters on timber structure (lots of drinking straws in a
stack) and cutting tool chip formation. When you rip, you're splitting
the fibres apart along their weakest plane. You don't even have to cut
the fibres themselves (much), just the weaker join between them. When
you cross-cut, you have to cut each fibre crossways twice.
On 29 Jan, 14:24, J. Clarke <[email protected]> wrote:
> Nice theory, but it doesn't explain why a blade that crosscuts just
> fine may requires the wood to be forced into it to rip.
The explanation for that is that the cross-cut teeth are the wrong
shape for ripping! A hand saw shows this most clearly, and a Swiss
army knife best of all. Crosscut blades are sharpened as opposed pairs
of knives to cut each fibre at each side of the kerf. A rip blade is a
single chisel edge to lift the fibre away from its neighbour. You'll
notice that it's possibel to rip with a cross-cut saw, trying to cross-
cut with a rip saw is very much harder work.
For most small circular blades there's little difference. They use
carbide inserts and are fairly sharp on every edge. The problem with
this much power in this little space is clearing the chips, not making
them. Look at an old non-carbide circular balde, or a really big rip
blade and you'll see the same hand saw tooth shapes re-appearing.
J. Clarke wrote:
> On 29 Jan 2007 04:58:14 -0800, "Andy Dingley" <[email protected]>
> wrote:
>>On 29 Jan, 05:37, [email protected] wrote:
>>>Why do rip blades rip faster?
>>
>>Because they're ripping and not cutting. Find a copy of Hoadley and
>>read the chapters on timber structure (lots of drinking straws in a
>>stack) and cutting tool chip formation. When you rip, you're splitting
>>the fibres apart along their weakest plane. You don't even have to cut
>>the fibres themselves (much), just the weaker join between them. When
>>you cross-cut, you have to cut each fibre crossways twice.
> Nice theory, but it doesn't explain why a blade that crosscuts just
> fine may requires the wood to be forced into it to rip.
It's not just theory, it's fact. A crosscut blade has many teeth and
therefore small gullets. It has comparatively more teeth in the wood at
any given time, causing more friction. Second, the gullets are too
small to effectively get rid of all the sawdust from ripping.
Chris
J. Clarke wrote:
> On Mon, 29 Jan 2007 19:57:12 -0800, Steve knight
> <[email protected]> wrote:
>>well it depends on the wood and the blade. but the harder the wood I
>>find more teeth can be faster. in tropicals I can rip faster with a
>>forrest 30t blade then any rip blade no matter how few the teeth.
>
>
> ??? What Forrest 30 tooth blade is _not_ a rip blade?
They sell a 30 tooth Woodworker II.
Chris
J. Clarke wrote:
> Calling something a "Woodworker II" doesn't make it a rip blade or not
> a rip blade, the number of teeth and the grind and set make that
> determination. Some Woodworker IIs are intended to be rip blades,
> some are not.
I suppose it's a question of semantics. I'd consider the WWII a combo
blade, not a rip blade, regardless of number of teeth.
Unless you get into the custom grinds, the WWII blades all have 15
degree ATB. This allows it to do crosscuts, but it will almost
certainly cut into its efficiency as a rip blade.
In my view a rip blade is dedicated to ripping as efficiently as
possible. Generally this means a small number of flat top teeth. Like
this, for instance:
http://www.amanatool.com/circular-saw-blades/heavy-duty-ripping-710200.html
Chris
Steve knight wrote:
> and I am saying my combo ww II rips faster and smoother then any rip
> blade down to 18t and it takes less power to do it too.
Givent that I haven't done the comparison, I can't argue with personal
experience. I wonder what Forrest could do if they set out to make a
pure rip blade.
Chris
[email protected] wrote in news:1170049072.379899.188220
@p10g2000cwp.googlegroups.com:
> Why do rip blades rip faster? They have fewer teeth than combination
> or general purpose blades, so the resulting gullets are larger. But I
> don't see most people feeding their stock that fast. So it doesn't
> seem like waste removal via the large gullets can be that big a plus.
>
> I would normally think that more teeth would = more cutting would =
> faster cutting.
>
> Anyone have any good links to articles about blades and tooth angles
> and such?
>
> Oh, and if a rip blade rips faster, will it also cross-cut faster?
> Ignoring quality of cut, of course.
>
A couple things come to mind... when you rip a board, you're going with
the grain. The board will come apart easier along the grain than it will
across it.
Another thing to consider is that more teeth = more friction = more drag
which means slower cutting speed.
If you want good links, you'll have to do a Google search yourself.
They're out there, I found a page in less than 5 minutes demonstrating
how hand saw teeth should be sharpened, with pictures even.
Puckdropper
--
Wise is the man who attempts to answer his question before asking it.
To email me directly, send a message to puckdropper (at) fastmail.fm
[email protected] writes:
>Why do rip blades rip faster? They have fewer teeth than combination
>or general purpose blades, so the resulting gullets are larger. But I
>don't see most people feeding their stock that fast. So it doesn't
>seem like waste removal via the large gullets can be that big a plus.
>I would normally think that more teeth would = more cutting would =
>faster cutting.
>Anyone have any good links to articles about blades and tooth angles
>and such?
>Oh, and if a rip blade rips faster, will it also cross-cut faster?
>Ignoring quality of cut, of course.
Take out a piece of veneer, or a thin cutting of wood (1/16" or less,
at a guess). Take a sharp utility knife, and make two cuts:
- one with the grain
- one across the grain
Decide which one is easier to cut, and think about how you might change
the design of the cutting tool to make it easier to cut the difficult one.
Alternatively, you could take a plane and try three directions:
- with the grain along the flat side of a board
- side-to-side on the flat side of a board
- any direction on the end of the board
Is there a difference? If so, then it is likely that different tools
(or different flavours of the same tool) will do best on different cuts.
Then think about what saw blades do. Are they cutting like a plane, a
utility knife, or something different? Look at a rip blade and a cross-cut
blade, and perhaps a combination blade, and see the differences in the
cutting method (shape of teeth, angles, etc.) You might also want to look
at a good saw blade catalogue and get an idea of the many different tooth
designs and what use the recommend for each blade.
"Prometheus" <[email protected]> wrote in message
news:[email protected]...
> On 29 Jan 2007 05:57:56 GMT, Puckdropper <[email protected]>
> wrote:
>
>>A couple things come to mind... when you rip a board, you're going with
>>the grain. The board will come apart easier along the grain than it will
>>across it.
>>
>>Another thing to consider is that more teeth = more friction = more drag
>>which means slower cutting speed.
>
> Possibly the case, but my understanding is that more teeth = smaller
> bites. Take bigger bites with the teeth, and you can feed faster, but
> you sacrifice a little polish on the finished cut- my guess it that
> doesn't matter as much with a rip saw because it separating fibers as
> well as shearing them, so you can get a better finish with fewer
> teeth.
>
Dancing with the answer. It's the angle of the tooth relative to the wood.
You've probably noticed that raising the blade too high when ripping makes
the job worse. That's because you're hacking rather than peeling. Angle of
your plane an analogy.
With carbide blades, only the edges of the teeth are excess drag, but I'd
say that was a negligible factor.
"Chris Friesen" <[email protected]> wrote in message
news:[email protected]...
> Steve knight wrote:
>
>> and I am saying my combo ww II rips faster and smoother then any rip
>> blade down to 18t and it takes less power to do it too.
>
> Givent that I haven't done the comparison, I can't argue with personal
> experience. I wonder what Forrest could do if they set out to make a pure
> rip blade.
>
> Chris
They do make a Pure rip blade.
Item # WW10206125
Description, WoodWorker 2, 10" 20 tooth, For fast rip of thick hardwood
with out burning.
Look here and look at the top item of the bottom chart.
http://www.forrestblades.com/woodworker_2.htm#custom
For the advanced table saw operator. Ideal for joinery and special uses.IZED
WOODWORKER 2 SAW BLADES
For the advanced table saw operator. Ideal for joinery and special uses.
"Chris Friesen" <[email protected]> wrote in message
news:[email protected]...
> J. Clarke wrote:
>
>
> In my view a rip blade is dedicated to ripping as efficiently as possible.
> Generally this means a small number of flat top teeth. Like this, for
> instance:
Early WWII's were and still are General purpose blades. In recent years you
can get WWII's that are "Customized" at the factory to specifically Rip, Cut
square bottoms for box joints or spines, and or to have different bevel
grinds to suite your particular needs.
http://www.forrestblades.com/woodworker_2.htm#custom
See the bottom chart to order specific needs WWII blades.
In article <[email protected]>,
Chris Friesen <[email protected]> wrote:
>Steve knight wrote:
>
>> and I am saying my combo ww II rips faster and smoother then any rip
>> blade down to 18t and it takes less power to do it too.
>
>Givent that I haven't done the comparison, I can't argue with personal
>experience. I wonder what Forrest could do if they set out to make a
>pure rip blade.
>
>Chris
My experience: I have a Forrest WW2, also a Dewalt 24 tooth rip
blade, an Oldham 40 tooth "Wizard" general purpose blade, and a few
others. The WW2 gives the best, smoothest cut in a rip, but it
is notably slower, and takes more force than either the rip blade
or the other 40 tooth blade. This is on a 1 1/2 hp contractor saw.
I suppose a 3hp cabinet saw might behave differently.
--
When the game is over, the pawn and the king are returned to the same box.
Larry Wasserman - Baltimore Maryland - lwasserm(a)sdf.lonestar.org
On Mon, 29 Jan 2007 19:57:12 -0800, Steve knight
<[email protected]> wrote:
>
>
>well it depends on the wood and the blade. but the harder the wood I
>find more teeth can be faster. in tropicals I can rip faster with a
>forrest 30t blade then any rip blade no matter how few the teeth.
??? What Forrest 30 tooth blade is _not_ a rip blade?
> same
>on the bandsaw. some wood rip with fewer teeth better some don't
On Tue, 30 Jan 2007 09:19:16 -0600, Chris Friesen
<[email protected]> wrote:
>J. Clarke wrote:
>> On Mon, 29 Jan 2007 19:57:12 -0800, Steve knight
>> <[email protected]> wrote:
>
>>>well it depends on the wood and the blade. but the harder the wood I
>>>find more teeth can be faster. in tropicals I can rip faster with a
>>>forrest 30t blade then any rip blade no matter how few the teeth.
>>
>>
>> ??? What Forrest 30 tooth blade is _not_ a rip blade?
>
>They sell a 30 tooth Woodworker II.
Which has what bearing on the question?
Calling something a "Woodworker II" doesn't make it a rip blade or not
a rip blade, the number of teeth and the grind and set make that
determination. Some Woodworker IIs are intended to be rip blades,
some are not.
On Sat, 3 Feb 2007 16:46:09 +0000 (UTC),
[email protected] (Larry) wrote:
>In article <[email protected]>,
>Chris Friesen <[email protected]> wrote:
>>Steve knight wrote:
>>
>>> and I am saying my combo ww II rips faster and smoother then any rip
>>> blade down to 18t and it takes less power to do it too.
I have some WWII 40T blades, but my favorite rip blade is a Freud 20T
full kerf rip blade.
The Freud leaves a great edge, and I can go get a coffee and come back
without burn marks!
P.S. NEVER leave a board on the saw and walk away!
On 29 Jan 2007 05:57:56 GMT, Puckdropper <[email protected]>
wrote:
>A couple things come to mind... when you rip a board, you're going with
>the grain. The board will come apart easier along the grain than it will
>across it.
>
>Another thing to consider is that more teeth = more friction = more drag
>which means slower cutting speed.
Possibly the case, but my understanding is that more teeth = smaller
bites. Take bigger bites with the teeth, and you can feed faster, but
you sacrifice a little polish on the finished cut- my guess it that
doesn't matter as much with a rip saw because it separating fibers as
well as shearing them, so you can get a better finish with fewer
teeth.
On 29 Jan 2007 04:58:14 -0800, "Andy Dingley" <[email protected]>
wrote:
>
>
>On 29 Jan, 05:37, [email protected] wrote:
>> Why do rip blades rip faster?
>
>Because they're ripping and not cutting. Find a copy of Hoadley and
>read the chapters on timber structure (lots of drinking straws in a
>stack) and cutting tool chip formation. When you rip, you're splitting
>the fibres apart along their weakest plane. You don't even have to cut
>the fibres themselves (much), just the weaker join between them. When
>you cross-cut, you have to cut each fibre crossways twice.
Nice theory, but it doesn't explain why a blade that crosscuts just
fine may requires the wood to be forced into it to rip.
Try ripping with a triple-chip grind sometime, then try crosscutting,
and you'll see a marked difference.