Newbie design questions

W

Wolf_HR

Joined
Jun 22, 2013
Messages
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I hope I'm in the right part of the forum to post my newbie questions... (at least, this thread might go into sticky thread as warning- look what happens when daft person thinks he can make a knife) I lack the skills of a bladesmith, but am an engineer entertaining the thought of producing knives on very small scale. I can go into details (and much more questions, inevitably) later if I don't get kicked out, along with this thread, from this subforum. :o

I've been trying to design a blade for a (friction lock) folder knife- it wouldn't be a traditional folder, but am not particularly fond of modern ('klingon', as I call them) designs. So, I was hoping to design a very sharp cutting instrument, preferably elegant, but 'modern-ish' (no link to hunting designs, various peasant or fighting knives, like Bowies and Navajas), but am at my own assesment failing miserably at doing so. The blade seems too thick, even if I've used probably too thin section (1.75mm, or 0.07") for the blade length (in this pic, edge to tip length is 85mm, or 3.35", blade width is 15mm or 0.6"), the overall 'blank' length in the pic is 105mm (4.13")... Lines seem to be all wrong at the tip even if I used distal taper (from 1.75mm to 1mm, starting at the middle line, at the ricasso), but am clueless how to correct it without a) changing first saber grind angle at the tip (which doesn't seem prudent), or b) adding a swedge of a sort, which I'm not particularly keen on doing (one reason is that it might add to 'aggressive look', which I'd avoid, or want to add to another version of the design). How could I improve the shape o the tip (I would be satisfied to get very good cutting performance from the recurve 'belly' to within half an inch from the tip), but would like ti improve on seemingly not so good performance at being stuck into stuff).

Another thing is the edge shape- I was hoping to use a local variant of D2 steel (which I'm told can be obtained quite cheaply), and I've used 36° included angle for cutting edge. Being clueless about particularities of various steels, I was wondering if that's an appropriate value for the material chosen. Thanks in advance, and I hope my questions/design doesn't seem to be too amateurish (and certainly, that I'm not coming off as a wannabee-ish type)...

loqk.jpg
 
Hilarious number or reads with no responses.

As a newb myself, let me ask a few questions and maybe get the ball rolling. What tooling are you working with? What do you want it to be used for? Given the amount of work that you will put into a knife, why would the price of the stock material be a concern? Is that 36 degree for just the edge with a chisel grind? Your primary bevel will be what 6 degrees?

.070" seems rather thin for a folder but probably not unheard of. It will be delicate for general use but not without its virtues.

-Sandow
 
let this be newbs helping newbs. Check out the stickies as there is a wealth of information in them. D2 isn't that much more expensive, but I would suggest an easier steel to work with the first time around like any of the cheaper, high carbon steels. Maybe look at a different design overall and look at doing a fixed blade first and focusing on basics of beveling, etc before dipping into friction folders.

What kind of setup are you working with? also fill out your profile as someone close by might be able to offer some assistance. Good luck!
 
Thanks guys, I appreciate the help. I've filled out my profile, but I seriously doubt there would be many people in my neck of woods to help me out (I don't think there are more than half a dozen blacksmiths in my country, and none of them would be involved in bladesmithing or anything of the kind)... It is also a reason why I didn't even consider designing a fixed blade- I'm over forty and have never-ever in my life seen someone carry a fixed blade (unless in a hunting party). Hell, carrying something bigger or fancier than a 2" swiss army knife will generally be frowned upon.

As for setup and tooling, my plan was induction heating (perhaps LF setup for heating the material, and HF unit should I choose to experiment with HT of the blades myself), and impression die forging or stamping (I'm quite certain I'd have no clue about designing a flashless forging process). It would be a small scale (say 3-4 blades at the time) setup- as a mech. eng., probably I'd look forward to designing the setup as much to designing a nice and useful blade (and learning as much as possible about both in the process).

Now, back to blade itself- it's supposed to be a simple pocket knife (le't say gent's, it sounds fancy), a general purpose (or no purpose at all) blade, used for light work, occasional outdoor use (fishing & camping- cutting lines and ropes, gutting an occasional fish, food prep, &c)... Here's few views of the offending blade:

j2mh.jpg

TIA

P.S. About D2 and mentioning the price- I sort of fancy what I've heard of the steel, and I mentioned the price because I've heard (but haven't checked yet) is considerably cheaper than what I've seen online, so it might be of interest to other members who use such steel. In case anybody's interested I can easily put up chem. composition (proper designations), recommended HT parameters, &c. I might even be willing to help in procurement if need to do so arises...
 
I think there are two things that strike me about your design as slightly off. The S curve down the blade, while attractive in appearance, seems like it would reduce the functionality somewhat and also make sharpening it harder. The other thing is that having the edge extend passed the shank makes it more exposed and probably creates a weak point.

Making it taller and then having a spine that wasn't perfectly straight would would help it look more like a carry knife and less like a steak knife. Going up to 2cm still makes it a fairly unobtrusive pocket knife. That would also make straight cuts in soft material easier in terms of steering.

-Sandow
 
I'm with Sandow, why the recurve on the blade? Why extend the edge out past the rest of the blade? I'm all for doing something different, and the joy of 3D modeling it is that you can get a feel for it before you commit to anything so it can be played with, but what is the purpose?
 
Thanks a lot. guys (bladsmth- your link didn't work for me, but made me search a bit and realize how ignorant I was on the subject). :)

Recurve, I don't know- I've seen quite a few blades with it and it looked nice, and since I saw it on BM 710, I figured it didn't adversely affect the cutting performance... As for extending the edge past the rest of the blade- I'll defer to your opinion and consider that it's a bad thing. My reasoning was that forcing the steel 'flow' in that direction during forging would somehow benefit the quality of the edge (slightly to the detriment of the blade stiffness). And additionally a perfect place to form a flash (which would then be removed and the edge ground).

Sandow, the remark about steak knife is hurtfully accurate IMHO. :) I think that was waht was bothering me without me realizing it. :thumbup: But am not sure about straight spine you mentioned- it's constantly radius almostr to the point, and there is also a distal taper.
 
I disagree with the comment that 0.70" stock is too thin for anything but a delicate knife. Opinels are used quite hard all over the world and are of thin stock. Will 0.70" stock baton through a concrete block? No, but it will slice through almost anything quite effortlessly. It's a knife, not a jackhammer or a pry bar.
 
medicevans said:
I disagree with the comment that 0.70" stock is too thin for anything but a delicate knife. Opinels are used quite hard all over the world and are of thin stock. Will 0.70" stock baton through a concrete block? No, but it will slice through almost anything quite effortlessly. It's a knife, not a jackhammer or a pry bar.
Click to expand...

A pocket knife is often the only tool you have. Prying and hammering may not be its primary design goal but they are going to see that kind of use in real life. I personally carry a thick blade that I have pried open cases, removed large staples from crates with, shimmied open locks with, cut wires, hammered bolts into place with etc... It is a beater. I have a thin fixed blade on my backpack that is great for more delicate use. Wolf's design is the kind of thing I'd use as a secondary. Good for some things but not capable of all things.

-Sandow
 
Not sure why it isn't working? Maybe it is because you are a registered user.
What the link was was an advanced search using the keyword "croatia". To do that click the "Advanced Search" at the top of the page, and then put the search keywork or makers name in the appropriate box. It got all these Croatian makes as hits. If you do the search, you will get this list as name icons. You can then click the maker's name and send then emails or PMs.


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Started by ohiostatefan, 06-15-2013 11:36 PM


Replies: 1
Views: 307
Last Post: Yesterday 04:57 PM by Wolf_HR

Forum:
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Registered: 02-02-2009 03:13 PMLast Activity: Yesterday 04:24 PM




Beckerheads in Europe?


Started by europeanoutdoorsman, 06-25-2013 04:02 AM


Replies: 10
Views: 188
Last Post: Yesterday 06:04 AM by woody_allen

Forum:
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ZLKnives
Registered: 05-25-2013 07:14 PMLast Activity: 06-25-2013 05:07 PM




Ikarus13
 
Sorry for necroposting, but I did some thinking and would (yet again) welcome opinions... Last few days I've been fiddling with the idea for a light use folder (say office use), and tried to go for 'elegant look', yet the blade curiously ends up being a sodbuster with loveless drop point (full grind, but hollow), with a bit of skinnerish look- which I do find elegant. And I thought a slipjoint would just about fit the bill.

3k30.jpg


To give the idea of proportions, edge length is 70mm (a smidgeon over 2 3/4"), handle length 88mm (a slightly less than 3 1/2"), and blade thickness 1.5mm (0.06 in, or slightly less than 1/16")...

cf1l.jpg


So, what's the verdict? TIA
 
The overall knife seems fine, but the lock bar appears to be a combination of the bar for a lock back on a slip joint. The Lock bar does not need that bent end. It should be straight. The blade will only need a small indent to fit, not the deep notch shown. This drawing may help ( scroll down a bit):
http://budgetlightforum.com/node/2093
 
Thanks for the tip, Bladsmth... I don't have much time ATM, but I set off to have it implemented, but in the process realised that the blade shape (edge sticking out of the tang) dictates this rather unorthodox shape. Pardon the hurried modification (I'll have to play with it a bit more to get it right- e.g. liners do not fully cover tang when closed, &c), but here's the view showing the crux of this problem:

vv43.jpg


But I liked your suggestion about the indent- it does make the knife more compact (only by a few mm) and I appreciate the help. :)
 
I like the blade shape in your second knife a lot better than the first.

That said, if you're going for a slipjoint design here, you're going to have to square/straighten up the end like Stacy mentioned. As it stands now, you'll have rock in the open position when pressure is applied against the edge. In other words, there's nothing to keep it from pushing farther backwards until the corner of the spine contacts the spring.
 
Oh, I think I'm getting it now- I should design it so that spring blocks blade rotation by physical contact with the back of the tang? In this design the surfaces aren't mated when the blade is opened and it will not properly lock (it will be fixed by reshaping front face of the spring and/or back face of the tang, so they're in proper contact)... Thanks. :)
 
I hope I'm not breaking forum etiquette, but I thought it's better to dig out my old newbie thread than to litter the forum with my new daft questions... Say I was going to make a knife, I thought the best way is to make something that would get used regularly and can be 'tested', so the best choice would be a kitchen knife. I'm not very fond of large chef's knives, and I think most people I know also prefer smaller knives for slicing and dicing, so I thought something like this might fill the role of 'primary' kitchen knife- 120mm (4¾") and 240mm (9½") OAL SS utility knife. Apart from welcoming comments and critique of the design*, I'd like to ask, since it's supposed to be a slicer, would 1mm (0.04") be OK for large-is knife of this type and what would be appropriate hardness of say AEB-L for this conditions. I think the edge would be OK if it was a tad under 0.01" with 18° DPS?

sppLa8v.gif


* I'm also wondering if SS bolster would be desirable and worth the hassle on such knife
 
How have your knifemaking projects gone over the past two years? Any completed photos?

Kitchen knives are a good starter knife project. Thin is the way to go. 1.5-2mm thick stock is good. AEB-L is an excellent choice. I think an edge of 15° per side would be better for a general use kitchen blade.
 
Thanks for the advice. :-)

Actually, didn't get to knifemaking yet- in the meantime I was working in a literal sweatshop which drained all my energy and will to live, and it took me a month or two to recuperate from the experience... :-)

But recently I approached major knife manufacturer in a hope to pitch them a crazy idea of mine, and in the process came up with something I believe to be a good idea of a locking mechanism improvement... So, right now I'm fondling their NDA I received- I have just finished several iterations of the idea and am preparing to send it out. (fingers crossed)
 
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