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Pictures of edge thickness of a few common knives

Posted by kel_aa 
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Pictures of edge thickness of a few common knives
November 25, 2012 09:57PM
I took some photos showing how far the knives fit into the gap of a micrometer set to 0.020" (0.51 mm), as this seems to be a common enough number when discussing edge thicknesses. Although this is not a proper metrology technique to measure angled surfaces, the error should not be significant as the the micrometer faces are hardended and precision ground. For reference, the diameter of the shaft is 0.255" (6.5 mm).

The knives are, in rough order of blade length, a Spyderco Calypso Jr, a Victorinox Rucksack, a Spyderco Nilaka, a Benchmade Triage, a Benchmade Nim Cub 2 (fixed blade), a Spyderco Military, and a Mora Firesteel Knife (fixed blade).


Some comments:

Spyderco Calypso Jr in VG-10: As from the factory was quite thin among these. The edge as seen has been reworked. The bevel is at 0.015" at approximately 10 dps and microbevelled at 15 dps.

Victorinox Rucksack in medium carbon stainless. Good reliable choice when weight conscious ie trekking.

Spyderco Nilaka in S30V: Originally it was full flat all the way to the edge. I put a 15 dps bevel on it. The small bit of the tip broke off when the knife was dropped (closed) on tiled flooring and the blade opened. The original grind was slightly uneven and as a result the edge follows some werid splines.

Benchmade Triage in N680: Edge angle >20 dps, but is not that thick at 0.013". Will reduce the dps in due time. The secondary hook cutter is very useful for my workplace as well as the rounder tip and disarming orange color.

Benchmade Nim Cub 2 in 154CM: Edge angle approx 17 dps at 0.016" thickness. I find this to be quite good for a production fixed blade and combined with a good blade shape, handle, and excellent sheath. I highly recommed this to others.

Spyderco Military in S30V: Edge angle approx 16 dps, 0.023" thick. I consider this to be / have been Spyderco's flagship model and is disappointingly thick. And overall not the best fit for city life.

Mora Firesteel Knife in 12C27: I have a perennial desire to turn Moras into workable knives by significantly thinning the grind. Usually, I set out to give it a high saber grind but can't make enough progress. Recently, I was encouraged by Cliff's sharpening video where he noted that some SiC loaded onto cheap hardware stones can make a difference of 10x the cutting speed. So I purchased a King 200x SiC water stone (the coarsest one available) and a 90x/600x aluminum oxide stone from Lee Valley. And a DMT 120x as a backup. In use, I noted the water stone wore itself at alarming rates and built up very thick sludges. Comparing between leaving the slurry/sludge on and wiping it off, I think it cuts faster the latter fashion. And in loading the Al2O3 with the SiC, I didn't see such a drastic improvement. Is the 200x still too fine for this work? In the end, the DMT plate still turned out to be the least unpleasant way of regrinding the knife so far, but it is still far from a desirable flat grind. Any suggestions?




Spyderco Calypso Jr:

Victorinox Rucksack:

Spyderco Nilaka:

Benchmade Triage:

Benchmade Nim Cub 2 (fixed blade):

Spyderco Military:

Mora Firesteel Knife (fixed blade):




Edited 5 time(s). Last edit at 11/25/2012 10:13PM by kel_aa.
Re: Pictures of edge thickness of a few common knives
November 25, 2012 10:13PM
So far the mora is a nice piece of work. It might sound odd but unless you go down to very low grit sand paper or stone (Cliff has that 24 grit one), you might want to consider treating it like an axe or a machete and using a file first.
If you have the room, and the tools it should work fast enough, at least for the rough work
Re: Pictures of edge thickness of a few common knives
November 26, 2012 01:43AM
Nice work!
Re: Pictures of edge thickness of a few common knives
November 26, 2012 01:51AM
Quote
kel_aa
In use, I noted the water stone wore itself at alarming rates and built up very thick sludges. Comparing between leaving the slurry/sludge on and wiping it off, I think it cuts faster the latter fashion. And in loading the Al2O3 with the SiC, I didn't see such a drastic improvement. Is the 200x still too fine for this work?

In general I don't agree with Murray Carter often as he generalizes rules that only well apply to the knives he makes out of the steels he makes, but I do agree with him on one issue very strongly and that is you should use waterstones (or any wearing stone) with some intelligence. On the more coarse shaping stones you can keep them very close to flat, at least in a practical sense by just sharpening taking into account where they are wearing. I normally still lap all my stones, but they are always very close to flat because when a region goes out of flat I concentrate on that area.

In order to get a dramatic improvement the base stone has to have little cutting ability. I have many (gifts) that will not cut very well at all a they don't break down so as the top layer wears they just get progressively finer. On these stones you need a slurry or within a very short period of time they turn into finishing stones. With a little intelligence you can take advantage of this if you have to sharpen several knives as you lap them once to get the aggressive and then take turns moving through the knives as the grit gets finer.

For shaping there is no reason not to get the most coarse stone that you can, but unless you really like the work, or really have no ability to run one, get a small 1x30 belt grind, due to speed of the belt moving you can easily remove material at an order of magnitude faster.
Re: Pictures of edge thickness of a few common knives
November 29, 2012 04:39AM
Quote
CliffStamp
but unless you really like the work, or really have no ability to run one, get a small 1x30 belt grind, due to speed of the belt moving you can easily remove material at an order of magnitude faster.

Not what I was hoping to hear, but yes, the suggestion is acknowledged.

Quote
styx
using a file first

The files I have on hand is certainly scratching into the metal, but don't bite at all (at least compared to the feeling with hot-rolled mild steel that I have a feel for). I'll give it a go when I have some energy.



Edited 1 time(s). Last edit at 11/29/2012 04:39AM by kel_aa.
Re: Pictures of edge thickness of a few common knives
November 29, 2012 08:35AM
Well Another inexpensive option can be sandpaper. Or concrete blocks (just a part of it is enough) as they are very corse and there are certainly enough vids of ppl using them. Only you really gotta be careful as they aren't consistent and you can do more damage than good