Liner lock 15n20?

R

Remyrw

Joined
Jun 17, 2010
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I'm thinking about trying my hand at a folder but have a question regarding the liner lock aspect. Is there any reason I couldn't use 15n20 if heat treated and tempered properly for the role? Essentially I'm trying to make a fairly thin knife and was planning on 1/8" 1084 for one side or more 15n20, 1/8" blade, whatever thickness works for the liner lock side. I'm still up in the air as to whether I'll put anything else on that side, but if I do it would be micarta or g10, but I'm trying to keep overall thickness way down without giving up the 1/8" blade.

My thoughts on the 15n20 are as follows:
1. Fairly easy to work with, and inexpensive so the inevitable goofs don't add up quite so fast like with Ti.
2. I can easily heat treat it myself, which I cannot do with any of the stainless options. I expect this to be a multi-try project so being able to do everything in house makes things a lot smoother.
3. It's easily available in thinner stock. Aldo has it in 0.072, 0.065 and 0.058. If I used 0.058 my final knife width could be as thin as .31" or so.

So, where am I wrong, or what am I forgetting or unaware of? This is not for a heavy use folder, though it'll be fairly good sized in length and height.

1/8" 1084 (or thinner 15n20 maybe) Frame
1/8" 1084 blade
X/Y" 15n20 frame with liner lock

I was thinking I could actually do a localized spring temper on the base of the lock using a focused torch. It wouldn't be precise but it would let me be sure the pivot area stays at the hardness I did the original temper for. I like a fairly stiff lock, but don't know how stiff the 15n20 would be in the various thicknesses and obviously it would vary depending on the height of the lock section. I'd divot as needed I guess.

My total folder construction experience is two kits from Knifekits.com so I'm looking at this as a learning project rather than a "perfect results" project. Any and all advice is appreciated.
 
I'm pretty sure the Montana guys, Shane Taylor, Wade Colter, Barry Gallagher, Josh Smith, Deryk Munroe, and a whole bunch of others have been using 15n20 liners for years. It seems to work quite well.

I've used o1 for liners a few times, but I mostly use titanium to save weight.

I would probably temper the whole thing the same, but it may very well work better at different hardnesses. I never tried that.
 
Good to hear. I was thinking the different temper just to help reduce fatigue on the spot that would be flexing over and over, not sure that really would matter with that tiny bit of movement but it is my understanding that that's kind of the point of doing a spring temper on something.
 
Sorry, I wasn't very clear there. I draw the whole liner to a spring temper. With the hardness anywhere in the 40's or 50's a 15n20 liner will be much stronger than titanium of comparable thickness. I really don't see any point in trying to make any other part of the liner any harder. It doesn't need to hold an edge so all you really need is toughness and fatigue strength. A spring temper will give you that. The only part that may be useful to have harder is the end of the lockbar and even then I don't think it would give enough benefit to be worth the effort.
 
I used it for my first liner lock, but I wouldn't recommend it for anything other than a prototype or learning, or maybe a dress piece. The only real draw backs in my opinion is that it rust easy and ti is a bit "sticky" on the lock face, 15 & 20, and most stainless steels also, get a bit "slick" on the lock surface. It'll work, but to me ti is just about the perfect material for a liner lock. That said I work in a salt water environment, and sweet on knives for 12 hours a day, your milage may very.
 
Good to know, Will.
In this case it should be ok. My primary purpose is to get a feel for things and some experience with it. I figure I'll probably make the same knife two or three times before I actually consider it a finished item and put it in my pocket. I'm up north and don't have much issue with rust so with normal care it should be ok. I might the same finish I do on some of my 1080 blades. It gives a blackened patina that's fairly slick and resists further corrosion very well. It's not a durable finish, but it's easily touched up and looks good with some scuffing. :) Assuming the eventual final product turns out as intended it will be mostly a white collar environment knife. If I'm going to be more physically active I generally bring an old CS Voyager that is cheap and tough enough to not mind the conditions.

I hadn't even considered the grip factor on the lock portion, given the sizing and such I'm looking at that shouldn't be an issue for THIS knife, but definitely something I need to keep in mind and I'm glad you pointed it out. I thought about doing Ti for this one, but after looking at prices I decided to hold off on that until after I've screwed up the first half dozen times. It's a lot cheaper to scrap mistakes made from 15n20 than Ti. hehe
 
One posible source for cheap, or free liner material is find someone with a woodmizer saw mill. I couldn't get Woodmizer to tell me what there blade alloy is, but they did confirm it's a high nickel mix similar to 15&20. I was checking into it for damascus as my Dad has a Woodmizer and I could get the broke blades. It wound up more trouble than it was worth for damascus, but to cut some liners out of it should work and is about the rite thickness.

Wear resistance is another issue, I've yet to have a ti liner wear out, but it didn't take long for the one I did out of 15&20 to wear, of course it may have been some surface corrosion as well.
 
Why do some people resist the use of titanium that is so highly recommended? It's not near as difficult to work with as many think and for liner locking folders it works very good for either liner side. Frank
 
I agree with Frank. Ti is not all that epensive. From ebay you can get a square foot of .063 to .080 6AL4V shipped free for about $40. That will make a lot of liners.

Ti is the material for the job, the other choice is stainless steel.

I would not recomend any non-stainless steel unless you are just making a template knife to be disassembled, and used as the cutting templates for the real knife.
 
Did 410 Stainless Steel fall out of favor completely for liners? I have 410 and 416 in stock. Both are hardenable, 416 is sulfurized and great for engraving, but I would think that the 410 would hold up fine for the application and the rust issue is all but gone. It is also available in thinner sizes than 15N20 and not that expensive either.
 
I've used bandsaw blade for liners- it worked OK. Just work for friends, I think I prefer stain resistant material for a knife I'd sell.
 
I knew this was coming. :)
Basically it comes down to trying to absolutely minimize the costs on this first attempt. Aldo, you have lengths of the 15n20 for under $10, that's enough for quite a few tries and I can do the heat treating myself. The 15n20 is less expensive than Ti for something I know I'm going to screw up repeatedly (and if not then I'll just keep trying different versions to see what I prefer). We're talking about something that most likely will never see the outside of the shop other than in my pocket just for the heck of it. Future work would most likely be Ti, I have no concerns with working in it, I just don't plan to spend $40 on the whole project, including some new tools needed.

If you guys think 410 or 416 would do ok without foil in a propane forge then I'd rather go that route, I'm just under the impression that I'll have significant decarb issues. I can get the temps needed, and obviously the quench is a non issue, it's just the decarb I'm worried about. I don't want to start with .07 and by the time I'm done I'm down to .03 of actual steel. :) My forge is about neutral to slightly reducing environment generally so if you think that'll be good enough for testing let me know. Again, we're talking test piece here, if I decide to do this regularly I'd be buying that sheet of Ti in a heartbeat. I'm tempted anyway, but I really do need to keep a sharp eye on my knife making budget.
 
Remyrw said:
Basically it comes down to trying to absolutely minimize the costs on this first attempt.
Aldo, you have lengths of the 15n20 for under $10, that's enough for quite a few tries
The 15n20 is less expensive than Ti for something I know I'm going to screw up repeatedly
Click to expand...


http://www.alphaknifesupply.com/ti-sheet.htm
6-4 Titanium Sheet - Standard Grade TS64-0040-085069S .040" 8.5" 6.9" $10 1

Not including shipping, but enough to do at least 4 folders & also under 10$.
 
Damn, now we're talking. That one you linked is thinner than I can use for this test but they've got thicker at still very reasonable prices. Awesome.
6-4 Titanium Sheet - Knifemaker Grade TS64-0080-094030K .080" 9.4" 3.0" $15 1
That's more than enough to get me going and within budget.
Thank you, Numbers. :) Looks like i need to get shopping with Alpha and see what else I need right now that they have so I can consolidate orders.
 
Yeah, Alpha is where I go for Ti and several other things. Great supplier.

Ti is not bad to work with, just cut it slow with fine teeth on a good blade. I've found when tapping Ti I like to go with a slightly bigger drill size than recommended for steel, like a #50 drill for 2-56 threads. This, and a good tapping lube like moly-dee really helps when tapping thicker Ti for frame locks. Cobalt bits work well.
 
Good to know, Salem. I don't think I need to do any tapping on this one, the only possible spot would be for a pocket clip and I don't plan on one for this guy. What's it like to grind and how does cutting it with an angle grinder work? That's how I do my general shaping right now but I can always use a fine toothed hacksaw for rough out before the grinder. The planned design is pretty angular so that wouldn't be a real issue. I'm still thinking about how to make the cut for the lock, but I have a feeling it'll wind up being very slowly and carefully cut by hand and dremel.
 
It dulls belts rapidly. Blaze belts work OK with it but 967 36 grit belts seems to do better. I've not tried abrasive cutting with Ti before. A slotting saw on a mill works well to cut the lock.
 
Ti cuts pretty easily as long as you keep it wet. Water, cutting fluid, 10w30, doesn't really matter what you use, just keep some sort of lube on it and it's not bad at all.

When grinding, belts and cutoff wheels seem to last longer if you go slow. If it starts to glow it will form oxides that will ruin a belt in a heartbeat. Dip in water often and use a sharp belt. If you're careful it should last a good while.
 
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