Measuring Blade Length of Traditional Folders

[WhittlinAway]

Is there a canonical, or at least customary, method of measuring the length of a traditional folder blade? I some times see measurements describe the length of the cutting edge (but, for a blade with belly is that the measurement of the straight line distance from heal to tip or along the arc of the belly?) or from tang to tip (but, what part of the tang?) but these both seem to leave room for interpretation.

To start the discussion with a concrete example, here are some photos of an A. Wright lambsfoot when the maker's website describes as having a 71 mm blade. Measured along the edge, 71 mm falls a bit behind the kick:

Zooming in:

I noticed that the end of the caliper was near the furthest extent of the bolster from the handle, so I moved the inside points of the caliper there:

So maybe that's it? The length from the end of the bolster to tip tip? It seems to apply to this knife, but I'm not sure whether that's applicable to all knives or makers of measurements.

Does anyone know whether there is a standard interpretation or method of blade length measurement? Barring that, I'd be interested in knowing how the folks here on the porch interpret the term "blade length". Maybe there's a consensus. Or, maybe not, which is fine, too. Let's keep this discussion good natured.

 

[Jack Black]

That's very interesting Greg Traditionally, in Sheffield (and also in UK law), the blade is measured from the front of the tang to the point. I can only think that those erroneous measurements have come about because Wright's do not run their own website

Edit - Actually, I just checked Wright's hand-typed 2018 price list, and the measurements given are 66mm, 71mm, and 80mm Maybe, they just 'can't do metric'!

 

[knifeswapper]

Can't speak for everyone else; but I offer two measurements. Blade Length is frame to tip in fully opened position. Edge Length is sharpened edge to the tip. I don't try and use trigonometry to figure curvature, etc - can't believe it would matter much except on a Kris.

 

[screened porch]

I bought a CRKT that was 0.25" longer than described (point to front of handle). Even though it was claimed to be measured point to handle.

 

[afishhunter]

Bolster to tip is what I was told, many years ago.
Those states that have (or had) blade length limits usually specified bolster (or guard in the case of a fixed blade) to tip for the blade length.

 

[WhittlinAway]

Thanks everyone for the quick replies!

That's very interesting Greg Traditionally, in Sheffield (and also in UK law), the blade is measured from the front of the tang to the point. I can only think that those erroneous measurements have come about because Wright's do not run their own website

Edit - Actually, I just checked Wright's hand-typed 2018 price list, and the measurements given are 66mm, 71mm, and 80mm Maybe, they just 'can't do metric'!

Very interesting, Jack. Wright's site says in a table that the blade length is 2 1/2" but in the text says 71mm, which is about 2.8. Another UK site that sells them says that the length is 6 cm or 2 1/2".

Perhaps the measurements in the price list are measuring from bolster and the others are from the end of the tang (which I'm guessing is about the location of where the kick meets the choil?)?

Can't speak for everyone else; but I offer two measurements. Blade Length is frame to tip in fully opened position. Edge Length is sharpened edge to the tip. I don't try and use trigonometry to figure curvature, etc - can't believe it would matter much except on a Kris.

Thanks Mike. That sounds like a great way to present the information. I agree that a straight line measurement of edge makes the most sense. My pedantic brain had to wonder, though.

Bolster to tip is what I was told, many years ago.
Those states that have (or had) blade length limits usually specified bolster (or guard in the case of a fixed blade) to tip for the blade length.

I'm assuming this is the same as Mike's "frame to tip in fully opened position"? It seems to me to be an intuitive way to measure.

 

[Jack Black]

Very interesting, Jack. Wright's site says in a table that the blade length is 2 1/2" but in the text says 71mm, which is about 2.8. Another UK site that sells them says that the length is 6 cm or 2 1/2".

Perhaps the measurements in the price list are measuring from bolster and the others are from the end of the tang (which I'm guessing is about the location of where the kick meets the choil?)?

It gets worse! How confusing for consumers Most UK sites would give the measurement from the end of the tang - the actual cutting edge - because that is the way the length is defined under UK law. However, I dare say a few sites just take their (mis)information from Wright's

 

[black mamba]

Greg, your last photo is exactly how I do it, from bolster to tip with a dial caliper.