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94384 Kenneth Stagg <kstagg@h... 2001‑06‑22 Re: scrub planes - blade radius
paul womack wrote:
> 
> r = 2.5"
> 
> So that's the radius Stanley ground a #40 1/2 scrub blade to.
> Wether it's the best radius is another question

Good question.  What are the factors that would determine the optimal radius for
a scrub blade?  Off the top of my head I get:

How strong is the person using the plane?
What type of wood is it being used on?
How wide is the blade (a given for each plane but which plane will you use?)

It seems that the tradeoff (assuming that you are trying to remove as much
material as possible for the least expenditure of energy) is between shortening
the "shear" line of the shaving (where the fibers need to be seperated from one
another) and the ability of the chip to bend as it passes through the mouth of
the plane.  Reducing the radius toward the minimum (1/2 of the width of the
blade) allows you to remove a greater volume of material for a given shear line
(right?) but leaves you with a thicker/stiffer chip.

Of course reducing the radius may also limit the utility of the blade as it
reduces the amount of material that you can remove per pass if you are not using
the maximum depth that you can handle.

-Ken


94386 Steve Knight <stevek@k... 2001‑06‑22 Re: scrub planes - blade radius

here is where I have settled 
http://members.home.net/steve19910/web_temp_pics/scrubplaneiron.jpg


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94388 jimbono@w... (Jim Thompson) 2001‑06‑22 Re: scrub planes - blade radius
BugBear calculated the correct ( or original )  radius of a scrub plane
blade to be 2 1/2 inches.

Thank you, thank you, sir!  I have been wanting that piece of
information ever since I started using the scrub plane I got from Steve
Knight.

The plane cuts as well as you could ask for, but I have always thought
that the radius was too tight.  I just went out and checked it.  It is
ground to a one inch radius.

 I did not change the radius because I did not know what to change it
to.  Now that I know, I will regrind it.

Thanks again for a good piece of galoot detective work.

Jim Thompson


94390 Steve Knight <stevek@k... 2001‑06‑22 Re: scrub planes - blade radius
On Fri, 22 Jun 2001 10:49:36 -0700 (PDT), you wrote:

>The plane cuts as well as you could ask for, but I have always thought
>that the radius was too tight.  I just went out and checked it.  It is
>ground to a one inch radius.
>
> I did not change the radius because I did not know what to change it
>to.  Now that I know, I will regrind it.
>
>Thanks again for a good piece of galoot detective work.
>

but remember without a tote you might not have the leverage to make it work as
well. I started wit ha less curved iron on the first ones. everyone said add
more curve (G)


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Custom made wooden planes at reasonable prices
See http://www.knight-toolworks.com 
For prices and ordering instructions.
To subscribe to my good deals/beta testing/seconds email list send a email to
gooddeal-request@k... 
Subject: subscribe  


94392 "Croxton Gordon" <lawyer@e... 2001‑06‑22 RE: scrub planes - blade radius
> BugBear calculated the correct ( or original )  radius of a scrub plane
> blade to be 2 1/2 inches.
>
It seems to me that the optimum curve would have an exposed depth equal to
your depth of cut (thickness of shaving), which would depend on the wood
species, grain nastiness, and your strength.  The other dimension would be
the width of the exposed iron (a chord?) which should be a bit less than the
blade width on each side, so that the shaving tapers on the edges to nothing
and you don't get tearout at the edges.

I've found myself wanting a shallower radius than the previous owners of
scrub planes.

Cheers,
Croxton, enjoying the heck out of his new/old 40-1/2.


94397 "Shannon Salb" <ssalb@l... 2001‑06‑22 Re: scrub planes - blade radius
> It seems to me that the optimum curve would have an exposed depth equal to
> your depth of cut (thickness of shaving), which would depend on the wood
> species, grain nastiness, and your strength.

Hmm, I don't think so.  The depth can be varied by raising and lowering the
blade (like all planes).  The aggressiveness can also be varied by the
amount of skew that you hold the plane relative to your plane's direction.

Sure, the amount of curve affects the function of the plane (and I'm no
plane scientist).  Too sharp and the plane is acting more like a gouge and
it will balk more than it needs to when the iron is not razor-sharp.  But
too shallow and you lose some of the effectiveness.  But I don't think you'd
want to change the curve depending on your wood, because 99% of the bang
could be gotten out of changing the height of the blade or the skew of the
cut.

(Well, anyway, these are my speculation.)

-Shannon


94412 jimbono@w... (Jim Thompson) 2001‑06‑22 Re: scrub planes - blade radius
You put a tote on mine. 

 What I object to with the smaller radius is the deep grooves that I
have to take down after scrubbing.  I dont mind taking a shallower cut
with a greater radius.

Of course, I am saying this without having actually used a larger
radius.  I may be back here later saying it is a mistake.  But I gotta
try it!

Jim Thompson


94380 paul womack <pwomack@e... 2001‑06‑22 scrub planes - blade radius
Having dipped out on a scrub today, I've been consoling
myself with some scrub-related net-surfing.
One of the great mysteries seems to be the radius of the blade.
So, maths and web time:
Obviously, we start we a NOS reference:
http://www.mjdtools.com/tools/list_071/20144.htm
(thank you Mr. Donnelly)

Now we need to calibrate: the page says the blade is 6 inches
long, and since we know the blade is for a #40 1/2,
(for cryin' out loud Jeff, it's a scrub plane, what were you
expecting?!)
http://www.supertool.com/StanleyBG/stan5.htm#num40.5
we know that the blade a 1 1/2 inches wide.

Pixel counting time.
left most pixel 14, rightmost 96, so 82 pixels are 1 1/2 inches, 54.6
pixels to the inch.
top pixel is 6, bottom is 334, so 328 pixels are 6 inches,  54.6 pixels
to the inch.
They match, which makes me happy.

corner of blade is 326 pixels, so the "curve" is 334 - 328 = 6 pixels
deep, which is
.11" (7/64")

The radius of this can be calculated:
http://www.egroups.com/message/oldtools/58360?source=1
r = h/2 + (l^2)/8h
r = .11 / 2 + (1.5^2)/(8 * .11)
r = .055 + 2.25/( .88)
r = 2.5"

So that's the radius Stanley ground a #40 1/2 scrub blade to.
Wether it's the best radius is another question

	BugBear


94382 "Nuno Souto" <nsouto@n... 2001‑06‑23 Re: scrub planes - blade radius
----- Original Message ----- 
From: "paul womack"  r = 2.5"
> 
> So that's the radius Stanley ground a #40 1/2 scrub blade to.


Sounds about right.  Similar to the L-N.  Nifty piece of 
investigative work, BTW.

> Wether it's the best radius is another question

I think it all depends on how deep you want each pass to go
to.  The more radius, the thicker and narrower the shaving 
we can take.

Cheers
Nuno Souto
nsouto@n...
http://www.users.bigpond.net.au/the_Den



94553 Larry Poffenberger <lkp@r... 2001‑06‑26 Re: scrub planes - blade radius
At 01:46 PM 6/26/01 +0000, Jaime Metcher wrote:
>snippage here

>If the grain is at all cranky, the standard radius (2.5") gives you a 
>choice between backing out the blade and taking a million tiny passes, or 
>getting tearout that looks like the aftermath of an artillery 
>bombardment.  I keep meaning to regrind mine - in the meantime I use it 
>only on well-behaved wood.
>
>Jaime Metcher

Hi Y'all,
As I've mentioned before, I often use a #3 with a Scary Sharp (tm) blade 
with a crown (gently curved) for hogging off  or preliminary smoothing of 
burled walnut.  It works well with the plane in a 45 degree, gross grain 
attitude.  With attention to grain and a sharp enough blade, I can avoid 
tearout, a real problem with burled walnut.

I think the reason you don't see any modern furniture with figured walnut 
is there isn't anyway to work it except with hand tools.  It's a real shame 
most people have no idea how extraordinarily beautiful wood furniture can be.

Regards,
Larry

Larry Poffenberger
lkp@r... OR
rustytool@r...
For sale and information at:
www.rosewoodandbrass.com


94556 paul womack <pwomack@e... 2001‑06‑26 Re: scrub planes - blade radius
Larry Poffenberger wrote:

> I think the reason you don't see any modern furniture with figured walnut
> is there isn't anyway to work it except with hand tools.  It's a real shame
> most people have no idea how extraordinarily beautiful wood furniture can be.

At the risk of driftin gently OT, you underestimate the "more power"
tendancies of
those people. There's no wood so gnarly it can't be sawn near to size,
and thickness sanded <> <>, turn the extractor on!!!

	BugBear


94547 Jaime Metcher <jmetcher@m... 2001‑06‑26 Re: scrub planes - blade radius
>From: "paul womack" > r = 2.5"
>> 
>> So that's the radius Stanley ground a #40 1/2 scrub blade to.
>
>
>Sounds about right.  Similar to the L-N.  Nifty piece of 
>investigative work, BTW.
>
>> Wether it's the best radius is another question
>
>I think it all depends on how deep you want each pass to go
>to.  The more radius, the thicker and narrower the shaving 
>we can take.
>
>Cheers
>Nuno Souto
>nsouto@n...
>http://www.users.bigpond.net.au/the_Den
>

If the grain is at all cranky, the standard radius (2.5") gives you a choice bet
ween backing out the blade and taking a million tiny passes, or getting tearout 
that looks like the aftermath of an artillery bombardment.  I keep meaning to re
grind mine - in the meantime I use it only on well-behaved wood.

Jaime Metcher



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