Linerlock material and hardware questions

[spatters]

I have some questions about linerlock design.

1. What type of and thickness of stainless sheet would be good to use as liners and spring for a linerlock? Does the spring have to be hardened?

2. What is a good size and type for pivot and screws on an approximately 7" overall length folder?

Thanks

Steve Patterson

[Ray Rogers]

My personal preference would be a liner no less than 050 in thickness and I usually use .062

If you use stainless steel then it must be heat treated to make an effective liner lock. Stainless steel is easy to work with which is why you will see it used in the liners of the vast majority of commercially made liner locks. However, titanium does not need to be heat treated and in my opinion (and in the opinion of a great many others apparently) it makes a far better lock. It is not quite so easy to work with though which is why you only see it on high end production folders and hand made knives. When a customer spends big bucks for a high end using folder I believe titanium is one of the reasons why.

Use any pivot you like. It makes sense to me to select the pivot according to the anticipated use of the knife - hard use, bigger pivot. The most common commercially available folder pivots forliner locks are the simple barrel pivot and the T shaped pivots that can be press fitted. I would use at least a 3/16ths pivot on a knife that size...

[spatters]

Thanks for the quick reply Ray. I am attempting my first linerlock and I don't know if I want to go to the expense of using titanium. Would 416 or 420 stainless be suitable for a spring and what kind of heat treating would be necessary (harden and temper)? Also I am confused about what size screws to use 0-80, 2-56 ect.

Thanks Again

Steve Patterson

[Ray Rogers]

I don't use steel liners so I don't really know what the heat treat is for the liners. But, I do heat treat some 416 for other purposes. The method I use is to heat treat 416 same as you would 440C, and don't temper at all. The 416 doesn't get all that hard so tempering didn't seem necessary for my purposes. If this is your first liner lock then titanium might be overkill for now but you should try it in the future. For now, almost anything will work as 'proof of concept'. In my liner lock tutorial I used a sheet of thin aluminum for the lock. It won't hold up in the long haul but it's cheap, easy to work, and it functions well enough for you to know if you built a liner lock or not.

As for screws, use them all according to your needs. I don't care for 0-80's on anything except the scales of very small knives but I have seen guys used 5 or 6 of them to hold the knife together. Generally, I think the 1-72 or 2-56 perform better but your choice may be influence by the type of screw you choose. For instance, a tactical looking folder might use torx head screws which have tall caps so a smaller screw would be the only way you could get the head countersunk. A button head or flat head screw doesn't need to countersink as far (or maybe not at all) so a larger screw might be possible. At this point, it really doesn't matter so don't get lost in the details. The important thing now is to build a liner lock and, if you don't like the way the screws you used worked out, build another one...and another one...and another until it's the way you want it. You'll have to do that anyway because there is simply no way you will get every aspect of the knife exactly as you might want it to be the first time. So, that's why my tutorial advocates using plain old aluminum to build a prototype or two until you know what you're doing. It's takes me about a week to build a really good titanium folder, it only takes me 5 hours to build an aluminum prototype...find out what's wrong with the design...and build another....

[JeffreyPrater]

I have been using 410 SS for liners, I heat treat it as directed in K&G Finishing Supplies:
1850 for 20 min and temper 500 for 2 hours, X2.

This has worked well for me, and is less expensive, however I have found that it requires a lot of extra time for the heat treatment cycles. You always risk the chance that heat treatment can warp the 410 also.

No doubt Ti is best, but 410 is working for me as I refine the process. I have one Ti framelock I made from Don's pattern and daily use for several months has shown no visible wear in. I have been impressed with the toughness of Ti.

[Don Robinson]

Originally Posted by JeffreyPrater

I have been using 410 SS for liners, I heat treat it as directed in K&G Finishing Supplies:
1850 for 20 min and temper 500 for 2 hours, X2.

This has worked well for me, and is less expensive, however I have found that it requires a lot of extra time for the heat treatment cycles. You always risk the chance that heat treatment can warp the 410 also.

No doubt Ti is best, but 410 is working for me as I refine the process. I have one Ti framelock I made from Don's pattern and daily use for several months has shown no visible wear in. I have been impressed with the toughness of Ti.

Congratulations, Jeff, on your framelock.

Want to join us in building another?