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System for numbering of gouge sweeps?

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System for numbering of gouge sweeps?

#1

System for numbering of gouge sweeps?

Dave Mount

>Is there a defined mathematical/geometrical relationship between the number of the sweep of a gouge or adze and the arc of the gouge? My impression is that the number must relate to the degrees of a an arc described by the profile, and the total depth of the profile is a function of that and the width of the cutting edge. By "depth" I mean the distance from the top of the cutting edge to the bench if you laid the gouge on the workbench with the concavity down.

To put the question in proper context, if someone (can't imagine who) wanted to forge a flat blade (of, say, an adze. . .just to pull an example out of the air. . .) into an arc of a specified number (say, #5) and wanted to make a single-use swage (hollow mold) from wood to pound the blade into to shape in, how would one know what geometry the hollow should have (i.e., radius and depth)?

Best,

Dave

Re: System for numbering of gouge sweeps?

#2

Re: System for numbering of gouge sweeps?

Dan Donaldson

>If you are talking about the sweep number for carving gouges, I don't think that there is a real system, at least universal. The Swiss and European gouges with the same numbers have different sweep, and it seems that the actual sweep also depends somewhat on the width of the gouge.

Re: System for numbering of gouge sweeps?

#4

Re: System for numbering of gouge sweeps?

Peter Evans

>Don McConnell wrote an article on just this topic that was on the Clark & Williams site, however when I just looked I could not find it. Perhaps if you email them? Article - "London-Pattern/Sheffield-List Carving Tool Sweeps".

Is there a sandard pattern for Scribing Gouges? Don't know.

Cheers, Peter in Sydney

Re: System for numbering of gouge sweeps?

#5

Re: System for numbering of gouge sweeps? *LINK*

Wiley Horne--So. Cal.

>Dave,

Here is the Auriou system of adze sizes, taken from Dieter Schmid's site (see link below), with some help from The Best Things and Japan Woodworker sites:

Sweep 3....10 degrees of circle.....blade width = 65mm

Sweep 5....60 degrees of circle.....blade width = 60mm

Sweep 7....105 degrees or circle...blade width = 60mm

Sweep 9....180 degrees of circle....blade width = 50mm

Translation notes: Dieter's site uses the word 'cut' where The Best Things refers to 'sweep'. Japan Woodworker characterizes the degrees (10 degrees, 60 degrees, etc) as 'Curve'. You can make out by inspection of photos that the degrees refer to the degrees of a circle.

Math: You can infer the radius of the circle of these adzes from the two pieces of information given--the degrees of circle, and the blade width. Here's the math, where

r = radius of circle

a = degrees of circle

w = width of blade

The trig involves using 1/2 the angle, a/2, and 1/2 the blade width, w/2. The formula is,

radius, r = w/2 divided by sin(a/2).

For example, take the Sweep 5 adze, whose blade represents 60 degrees of circle and is 60mm wide. For that adze,

radius, r = (60mm/2) divided by sin (60degrees/2)

or, r = 30mm divided by sin(30), and since sin 30 = 0.5,

we get, r= 30mm divided by 0.5 = 60mm.

We know this is correct, because a chord (the blade width) across 60 degrees of circle is the same as the radius of the circle. This is the principle of hollow & round sizing, which is a whole nother thing....

It's possible Joel is on top of all this, as he does lots of business with Auriou.

Wiley


Dieter Schmid site; Auriou adzes

Re: System for numbering of gouge sweeps?

#6

Re: System for numbering of gouge sweeps?

mikew

>Wow. My head has a deep, deep ache now for some reason!

Fascinating math. I wouldn't have had a clue how to figure this out.

Take care, Mike

Re: System for numbering of gouge sweeps?

#7

Re: System for numbering of gouge sweeps?

Joel

>Below is a rather poor JPG of the "standard" london sweep chart taken from out catalog. Most English carving tools makers follow it, this particular one comes from Ashley Iles. European sweeps are lightly different and depending on manufacter sweeps will vary slightly because of the difference in the actual swage blocks used to make the tool. Our catalog, and just about every carving catalog has a table like this or in a difffernt format in full size so that you can pick a profile. (I don't know if the jpg will come out full size)

Within a manufacter the tools of a given sweep, made about the same time period, both incannel and outcannel will have matching identical curves.

Scribing Gouges are another matter. As far as I know real ones are no longer made. When they were they were made both incannel and outcannel to specific radius and were used by patternmakers and scribing certain joints. Those should match maker to maker.


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Re: System for numbering of gouge sweeps?

#8

Yabbut

Wiley Horne--So. Cal.

>You've mastered making those incredible saws, which is a way higher achievement.

Wiley

Re: System for numbering of gouge sweeps?

#9

Re: Excellent, thank you!!!

Dave Mount

>Just what I was hoping for -- thanks so much!

Dave

Re: System for numbering of gouge sweeps?

#11

Re: Exactly, thank you!

Dave Mount

>

👍 This page answered my questions

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