Colin

[Colin]

That clears it up. I was fairly confident that I had the right grind, but that confirms it.  For handed-ness grinds, we would want to cut the bevel down on the inside edge of the blade (holding knife point directly away, spine side up, with the bevel facing our other hand) My opinel no 12 carbon is relatively enormous as far as pocket knives go (4.75 inch blade, nearly a foot long including the handle) so I was most curious about a chisel grind on that knife for ease of sharpening as it’s more of a field knife used for cutting seatbelts and hacking through plastics in mangled cars as well as a camp knife. I keep a 20 degree double bevel spyderco kiwi for cutting oranges and other food stuff while on shift.  I can say with confidence that I think I’m going to try to knock down that tiny secondary bevel I put on it and only use 1200+ stones for taking off that burr. Changing the bevel like that took off a substantial amount of metal, so I’d only suggest it be done when you’re absolutely confident you want a chisel grind. Opinels are kind of a “do what you want, it’s your knife, we just stuck a good piece of steel in a chunk of wood” and are dirt cheap, so overall I’m very happy with my change, but my other four are staying double bevel. I have five opinel folders in my house, I really should cut down!

[Colin]

Your point is valid, in that softer metals can take a finer bevel due to glass’ brittleness, but you also said yourself – that edge will fold, and if it folds within the first stroke of the blade (such as with hypodermic needles) then all subsequent incisions will be tearing cells instead of cleaving them. There’s a reason glass and diamond blades are used in ultramicrotomy. But as we said, the risk of chips from the inherently sharper, but more brittle glass type blades getting sheared into the wound is why they’re still not fda approved. And like you said, given applications are everything. I am purely arguing surgical instruments and cell histology, where what we would call a toothy edge is not what you want when you’re bisecting tissue. At a 100 micron level, everything is toothy, but it’s not what we’re talking about because at a microscopic level, everything is irregular.

 

Also not sure why you’re picking on a maker of ophthalmic surgical blades. Ophthalmic surgery is by far the most demanding type of surgery with regards to knives used. I haven’t done any research into them, are they a fraudulent company? Because glass knives are used in ophthalmic surgery, particularly radial keratotomy, one of the only procedures done on the human body using diamond knives.

[Colin]

Without getting too much further into it, you’re also looking at the crystalline structure of the elements evolved beyond the sharpening when it comes to the obsidian vs steel argument.

 

 

It’s basically the works of ultramicrotomy starting to bridge into surgery. The diamond knives of ultramicrotomy are used to create 2000 radial cross sections of a single hair, or 100 cross sections of a single red blood cell. That’s how fine we’re talking when it comes to the obsidian and diamond knives. The edges are not sharpened, they are made using fracture lines.

[Colin]

Fish monger/butcher gloves. Good idea!

[Colin]

tcmeyer wrote:

Incision points aren’t slippery tissue. Have you ever disassembled the insides of a big critter?

I’m really making a meaningless semantic argument, so I mean no offense.

I’ve dressed game. But I’ve also done my time in hospital rotations and field deliveries and all kinds of nasty trauma. Amputations aren’t a big deal. They’re slippery to hands, not knives sharp enough to shave hairs. It’s simple biology, less tearing is ideal on a living creature, damaged cells cause inflammation. Less damaged cells, less inflammation, faster healing. And surgical cuts are very different from field dressing game. Most slippery piece of flesh I’ve ever held is umbilical cord, and our OB scalpels melt right through them.

[Colin]

On recommendations, I ordered the 800/1k, 1.2k/1.6k, and a set of 3.5/5 stropping paddles. I’ll stop by the hardware store Sunday and see what I can do about getting that vise setup going as well. Really excited!

[Colin]

tcmeyer wrote:

 By the way, I have photos which show that even scalpels are made with a toothy edge. The packet I bought off Amazon is ground both sides with about 600 grit, and then polished only on one side to leave the toothy edge. This stands to reason as you need a toothy edge to bite into slippery tissue.

Completely irrelevant, but

Surgical scalpels should not have a toothy edge. It’s actually a big point of contention in the medical community with regards to obsidian scalpels, which have been proven in animal studies to drastically reduce healing time because under a microscope, a steel scalpel, no matter how sharp, will tear along the line of incision, whereas obsidian scalpels will actually cleave individual cells in half. Less damaged tissue, less inflammation, better healing. The reason we don’t have them in the operating theater yet us because of concerns that the obsidian blades can chip easily and leave slivers in the flesh. For biology slides, scalpels of glass are used for primary divisions and then slide cuts are made using diamond scalpels, which are prohibitively expensive but obviously very clean cuts at a cellular level. The idea is a bevel so fine that the friction line is so microscopic that it doesn’t even need a bite to sink through flesh. Also, flesh isn’t actually that slippery and incision points aren’t exactly trying to shave a tomato, all you want is clean cuts with a minimum of inflammation-causing tearing.

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Gib Curry

[Colin]

*medic here*
hands, feet, and anywhere on your head will always bleed the worst when lacerated due to the large number of capillaries in those areas. If you’re on a blood thinner like warfarin for atrial fibrillation or even take baby aspirin daily, if you have an underlying clotting issue, even nosebleeds can exsanguinate you and be dangerous. When injured, do not remove the old dressing if it soaks through, add more dressings and direct pressure until it stops. If you’re prone to nicks here and there and take blood thinners, there is a coagulation powder that can be found at any drug store called “woundseal” and is essentially civilian quik-clot. It’s only about six bucks and a single package can stop a major laceration. Hurts like hell, but works great, we use it in the field.

As for home made tourniquets, a belt works well, but any cloth will do, just wrap it around you, two inches above the top of the incision towards your body, and get a stick, put it under the cloth and twist it to increase torque on the wound. If that doesn’t stop it, add another tourniquet two inches above that. If that fails, add another!

Got a call, gotta go. But everyone here should have a package of wound seal, and stay safe!

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CliffCurry

[Colin]

With a typo, lol. 17 each side, 34. Used an angle cube. Never said I didn’t have one, I used it on the knives I could while hand sharpening with my basic whet stones. Had it once I had to get a set of spacers fabricated for my rsv mille r upright handlebars with an angled top triple tree. It’s a pretty common tool alongside a digital slide caliper, and maybe mine isn’t overly accurate, as it was a $25 one, I’m sure you guys use much more accurate tools. And like you said, without a base, my hands and slow stropping motion (what is the term you guys use for the passes?) Were the only stability, so I can’t be certain of my angles yet, but I did see a video a while ago explaining why the angle cube was a good idea due to the clamp not holding blades at the correct angle, so I think I’m in the ballpark, but obviously still an utter newbie.

[Colin]

Copy that evil twin, thanks. (I’m not going to buy the base when I have blocks of granite and 3/8 plate steel sitting in my garage, I was just curious for short term mounting until the tech college down the street is back in session, I just bribe the shop to do under the table stuff for me because my garage has no space for more floor tools or 220 outlets, I have to unplug my dryer to weld) I’ll make due, though that panavise setup razoredge has is mighty nice looking, I’m leaning pretty strongly towards that

 

That tormek jig is very cool. It’s just the small knife jig, right?

[Colin]

Excellent replies everyone, I’ll be taking everything said into consideration (I got an angle cube a while ago, so that part is sorted) and a plywood base is just temporary, I can see why it would be a little light, I have some heavier mdf/hdf lying around that I can do an 18x 18 base out of and clamp it to my table as well. I’ll get a better base from granite once I have some more time in a few weeks (I’m a medic, so my shifts can make my free time a little hectic)

 

Also, evil twin, if it makes sense, I’m starting with the basic system because it was a gift, and it’s easier for me to put money into it than ask for money towards the better system instead when someone wants to buy me something (which can also seem a little rude to the buyer)

From what I read, the ball joint arms make a world of difference. Should I buy that first or a set of finer stones and strops?

 

My first plan for breaking in the stones is next week to do something I saw on chef steps, taking old silverware butter knives and making steak knives out of them. I did my EDC opinel carbone #12 and spyderco kiwi last night out of curiosity (both are solid rescue knives that get used a lot alongside my leatherman raptor in the field) but I’m on duty for the next 72 hours, so I’ll try to get it set up on Sunday.

 

And razoredge, I like your setup a lot. What model panavise base is that? I don’t have any of my old steel cutting tools to make a blank for the base, so I might have to try to fix my ancient steel miter. Not having a drill press for a few years has been such a pain in the ass!

[Colin]

no pictures of my amateur trials, but I did an Opinel number 8 carbone to 40 inclusive, a spyderco kiwi to 40 inclusive, and the shitty kitchenaid I make my roommates use to 37 inclusive. Still not as sharp as my factory Asai Hayabusa, but getting there! Will likely get there with the 800/1k and 1.2k/1.6k stones and a proper base on sunday!

[Author]

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