Testing for sharpness?

okay, one more shot after some additional stropping, gotta wait til Monday for the new thread anyway. Two times, stuck to one spot each, mostly, still got very different numbers even just a quarter inch away.

belly

30 +++++
40 ++++
50 ++++++X+++
60 ++++++
70 ++++
90 +
00 +

straight (in front of that pesky stud)

30 ++++++++++++ (almost all 35g)
40 +++
50 X+++++
60 +++++++++
70 +

that came out weird, but like I said, even a quarter inch played a huge role, especially so close to where I start the blade on the stones/strop. Makes me want to go with opening holes.
 
took apart 3 disposable Bics and checked them on this thread, lousy results. I damage the edge immediately on all cuts. A third of the cuts were at 80g, only a quarter were 50 or under. The edges were mangled under magnification.

I also tried the plastic ruler to see what the thread broke at, was pretty close to 1.5kg (1470-1540)
 
Yes even 200g is not really dull if you compare it with spine...

Did you try split the hair?

I recently get 30g on Cold Steel ODA with 420 sub zero quenched. What surprized me it is doing better then INFI at least at the first steps - it sharpens better - I got 30g

20 ++++
30 ++++++X+++
40 ++++
50 +++

It does whittle hair as no any blade I try to do this before with long thin shaving. And after 9 cuts of manila rope it holds edge noticible better!

420: 30 - 50 - 50 - 60 - 50 - 60 - 60 - 70 - 80 - 70
vs
INFI: 40 - 60 - 70 - 70 - 80 - 80 - 80 - ?? - 80 - 80

I expected it to do worse then INFI eventually, but I thought it will be worse right away.

Thanks, Vassili.
 
I split hairs every now and then, it's a little tough because mine is curly. I've never gotten anything like your youtube videos, mine bends out of the way or snags and gets severed because of the natural twists & turns. I usually hold the hair against something and shave off bits. But I rarely attempt to sharpen that far anyway.

420HC beating INFI, Cliff would love this data. I wanna try something lower carbide. The M2 sharpens easily enough, but its time to maybe do some 1095 & 52100. I also have to see if I can get my zdp up to par.
 
420HC beating infi doesn't surprise me, I've gotten it sharper than most everything else, and I'm just a guy with a lanskey and a homemade strop. The problem is it doesn't stay that way very long.
 
Well, I doubt it will beat INFI in long run. It is just first 9 cuts I am talking about. Infi from 80 on 4th cut went to 120 on 400th. We shall see how 420 will do after 400 cuts.

And this is not 420HC. This 420 sub zero quenched - old 2002 Cold Steel ODA made in Taiwan.

I will do full report when I done.

Thanks, Vassili.

BTW. I just thought may be your pick on 30 is just your weight limitation or setup? Like it measuring for some reason only from 30? This is why I use stronger thread to see results on the weight working range.
 
the scale measures in 5g increments, and I did get one cut with the knife that only measured 10g, obviously some sort of delay in the display response. I will get some lighter thread and see if the measurements drop.

I thought Cold Steel was using 420HC with a cryo, it will be interesting to see what J2 does.
 
hardheart said:
the scale measures in 5g increments, and I did get one cut with the knife that only measured 10g, obviously some sort of delay in the display response. I will get some lighter thread and see if the measurements drop.

I thought Cold Steel was using 420HC with a cryo, it will be interesting to see what J2 does.
Click to expand...

No SaMX and you are right it is 420HC - I just checked.

Thanks, Vassili.
 
1 Open up a telephone book.
2 Fold up the edge of a page to a 90 degree angle, about 1/4 to 3/8 inch high.
3 Push cut down (gently!) on the upturned edge.
4 Knife is sharp if it cuts to the fold without mashing the paper.
Greg
ps telephone books are cheap and have lots of pages.
 
hardheart said:
the scale measures in 5g increments, and I did get one cut with the knife that only measured 10g, obviously some sort of delay in the display response.
Click to expand...

Yeah it is much easy to use a scale that has very little or no display response. The problem is on the ones with a delayed response, that it waits for the measurement to stop changing before displaying it, and since the load changes so quickly when the thread cuts that it might miss the point of highest load.

Greg: that is a favorite of mine as well. Problem is that it is only pass-fail. You have no idea of how close you are to passing it. Btw. rumor has it that Perrin used to test edges on cigarette paper like this :eek:.
 
This is why I do not use my electronic jeweler weights, which I bought for this testing. I have to use spring weight because they do not have delays.

Thanks, Vassili.
 
I don't think it's too far off on most cuts. I have to keep an eye on the display though, many times there is a quick jump in the number (10-15g) right when the thread severs. I don't know why I got that one really low number. Could have been another error somewhere; me slicing, the thread was damaged, etc. A display delay seems pretty likely, though (hopefully not something generally more than one increment-5g).

I'd like to get more accurate, but we're still facing multiple testers, multiple test media, multiple measuring devices, multiple jigs, so on and so on.
 
Perrin takes a cigarette paper, folds it, stands it up, & then cuts it in two. From his review site that is still up.

http://www.geocities.com/Hollywood/Set/2292/nativerev.htm

For sharpness I use Murray Carter's three finger test, then stand up a rolled up piece of telephone book paper and slice it in half. If not I'll check out the edge with a loupe and sharpen again.

For slicing I'll cut manilla rope, or hopefully some buck hide & hair this weekend. Hopefully big buck hair.
 
Now it is kind of surprising and strange:

10 12 15 20 25 30 35 40 45
420 70 70 80 70 80 80 80 90 70
INFI 70 80 80 80 80 90 90 90 90

So even after 45 cuts 420HC sub zero quenched better then INFI in 1/2" manila rope cutting test with sharpness measurement on thread!

This is really strange. It is not suppose to be this way! I choose Cold Steel 420HC to set low range of the scale to rate other steel between 420HC and INFI. But results are kind of surprising! I expected 420 to be far less edge holding then INFI, but it shows if not superioir but for sure same or better results!

Thanks, Vassili.
 
I did a test on some 100% mercerized cotton

00++
10++
20++++
30++X++++
40++++
50++

I also have some 40 wt rayon, but that stuff is a hassle to attach, I'll need a better jig (the mercerized cotton was slipping a lot as well, wasted several cuts because of it)
 
HH:That looks like a much better distribution :thumbup:. I found that on very sharp edges and yours certainly looks like one, it is easy to catch the thread when setting it down on the thread. A few strands of the thread are cut that way and the thread cuts very early. Those are probably the 00. Same if you tilt it a little you might get some pretty high numbers like those 50. I would simply discard those, but since you are doing a statistical analysis it doesn't matter.
 
hardheart said:
I did a test on some 100% mercerized cotton

00++
10++
20++++
30++X++++
40++++
50++

I also have some 40 wt rayon, but that stuff is a hassle to attach, I'll need a better jig (the mercerized cotton was slipping a lot as well, wasted several cuts because of it)
Click to expand...

Excellent results! This 00 kind of strange - is it because scales has some delay?

Thanks, Vassili.
 
I think so, unless I had some 9g cuts, lol

and that lighter stuff doesn't cut very cleanly, the separate fibers come apart pretty easily. Now I understand what you were posting about in the other thread, HoB
 
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