Perfect dive knife.

[ickledevil]

Hi all Mr. X has inspired me with his post about effsub (sp?) knives.
I've made a vouple of knives and straight razors in the past and considering making a dive knife, so all suggestions on design, materials size etc appreciated, hopefully if we can decide on a perfect design i'll try making it with a tutorial to go here. So let the ideas commence.
Joe

[geogiann]

--material aisi 440A, aisi 420 (more appropriate for salt water). plus hardening
--size small (10cm minus blade), good grip (with hand protection)
--one wavy cutting edge for rope and naylon
--for spearfishing use should be like a stilleto (dagger), for fish euthanasia
--easy and safe reach, at any position the diver may be (usually the knife should not fall out when the diver removes the safety)


ps. same time ago, i designed a knife, I had it cut with lasercut, and gave it to a Cretan knife craftsman (the ones that have visited Chania in Crete know ). The result was a knife that could cut just looking it.... but it was made out of aisi 316L ...its tip bended while cutting butter

[ickledevil]

Shame about the knife.. was it hardened?
I agree on the choice of steel, although hardening stainless is I understand a little harder than 01 etc. Have been told there is a type of damas that is stainles after hardening, will email the manufacturer to see about that. As much as i agree stainless is the way forward, I wish there was a way to use 01 tool steel, as its both easier to work and will hold a better edge, although stainless will stay useable longer it is harder to sharpen and wont sharpen quite as keen. Agree with the stilletto shape although how wide a stilletto I dont know, part of me says narrow like a old british commando knife the other says wider more like the old omer flat hunt. I disagree with the serrated or wavy edge though but would possibly add a dedicated line cutter. Mainly due to the fact the serrations are harder to maintain and keep sharp and only of real use sawing through very thick line although a serrated section possibly half the length of one side could be useful. A razor sharp straight blade will cut just as well on all but the thickest ropes. Also think I'd go more than 10cm blade, maybe 12cm, more of a cutting edge to use when slicing and dressing fish (which I know many people use their dive knives for.) As for handle agree good grip is imperitive am torn between a solid metal knife, same thickness like the effsub knife mentioned before or adding handles probably stabilised micarta or similar bonded to the metal and pinned too. Although this no matter how well done will add an area difficult/impossible to clean, that could trap water. As for sheath I agree should be in safe and secure unless you really want to remove it (a lanyard hole in the blade is essential.) Im thinking a kydex sheath, heat molded for a perfect fit and possibly covered with neoprene to allow attachment to suit if desired.
Great points and keep them coming, if anyone cares to upload a picure or diagram of their ideal knife feel welcome
Joe

[Pastor]

Originally Posted by geogiann

--material aisi 440A, aisi 420 (more appropriate for salt water). plus hardening
--size small (10cm minus blade), good grip (with hand protection)
--one wavy cutting edge for rope and naylon
--for spearfishing use should be like a stilleto (dagger), for fish euthanasia
--easy and safe reach, at any position the diver may be (usually the knife should not fall out when the diver removes the safety)

I'll take your word about the steel but that's what I would say was about my perfect knife with a simple lock on the sheath along with a rubber loop to give added security.

[irtrogdor]

Try Dendridic cobalt as a "metal". Doesn't rust. Ever.

here's the website of the best manufacturer I know of.

Here's part of an email the craftsman himself sent me:

"
...At the time, we were out of our 1/8" dendritic cobalt bars. I am expecting my next shipment around the middle of February [08]. The bars are 1/8" x 1 and 1/4" x 10" and they are $75.00 each. We send working instructions with the bar(s).
Please let me know if you want place an order, and I will reserve the bar(s) for you. Or let me know if you have any other questions.
"

my dad has a folding knife from this guy, and its amazing stuff. doesn't ever corode and it stays sharp for years.

[Mr. X]

Cobalt steel is tough. Having broken 4 or 5 regular drill bits drilling stainless steel flounder spoons I discovered cobalt steel drill tips: stronger, faster, better, longer lasting. Don't know what its like for knives though (but sounds like irtrogdor does).

Re. dagger blade, I would definitely go for a flat, slimmer blade - like your Omer - at least near the top section. I have a spearo knife with a wider blade & a diamond-shaped cross-section. I reckon it takes a little to much pressure to insert it - which risks it skating off (once in, of course, it does more damage). The diamond cross-section makes it diffult to sharpen.

My preference would be for a plain, flat, steel handle that is part of the same piece of metal as the blade - simple, strong, effective, flat, streamline, unobtrusive (although harder to remove from the scabard perhaps and less comfortable in the hand, esp. if you don't wear gloves). Omer Mini Laser size & shape blade (most would probably prefer the regular Laser size, or bigger, I suspect).

I agree that a serrated edge it probably difficult to make & sharpen but I reckon it is essential (or desirable) if you only carry one knife. Needle files or a chainsaw sharpener might be the way to make/sharpen them.

[ickledevil]

Mmmm interesting on the steel.. although $75 for the bar is a little scary! Mind you the damascus I mentioned earlier is more.. still waiting to here hw true thrier stainless statement is. product is called damasteel.lol. So serrated edge it is then im still thinking with only half the edge serrated to still allow fish dispatch without reaching the serrated part. and for both ease of use and care I agree with the plain handle as mentioned above. Anyone care to do a diagram of what we have so far?

[irtrogdor]

$75 is a lot. That's the reason I haven't built my own yet. but, assuming you don't loose it, you'll never have to get another knife again.

[Newbie_spearo]

wouldn't that bar make more than one knife though?

[irtrogdor]

very true - if made stiletto style a bar could make at least two. Easily three or four with some fancy cutting.

[Newbie_spearo]

Tell you what, you do some fancy cutting and make a few and I'd be very interested in buying one! I could get some handle designs going and pm them to you?

[irtrogdor]

Hehe... I wish I had that kind of shop to do that kind of work. And some money to start off. Actually, I'm surprised that the guy I linked to hasn't designed some sort of dive knife yet. It would certainly fill a need.

[Newbie_spearo]

I'm looking at making my own stringer, but thats a hell of a lot easier and less fiddly than a knife. I just got a price on some 5mm stainless steel. It comes in 4m lengths for only AUD$33 I figure with 4m of it I can make about 20 of them. Just gotta get some SS cable but that shouldn't be too hard, just gotta find out the cost. Let me know if you want me to whip up a handle design - not that I'm the most artisticly talented.

[ickledevil]

Give us a design by all means... be interesting to see.

[Mongrel454]

Newbie got talents....

Cant wait to see these pics