Folder Questions

[SHostetler]

Hi,
I am starting to gather materials to build a liner/frame lock folder with caged bearings. Based on some advice I was recently given, I'm planning on boring .031 deep pockets in the blade and the liner. With a .020 washer/race in the liner, this should give me about a .020 gap between the blade and liner. Where I need some help is with the thickness of the titanium liner/frame. What is the minimum thickness ti that I would want to use?

Thanks,
Steve Hostetler

 

[Bob Ohlemann]

Steve, there are a lot of variables in folders and any dimensional change can have an affect on everything else. First, are you making a frame lock or a liner lock? How thick do you want your finished knife to be? I like to work from a plan on all my knives but, it is hugely important on folders. Usually the only thing I don't know the exact dimension of before starting my folder is the blade thickness. I determine final blade thickness once the backspacer is finalized. If you don't have a surface grinder, that may not be an option for you. You may need to set your bearings to make the difference between the blade and the backspacer. Because I set blade thickness last, I do not pocket my blades, only my liners. So in a roundabout way of answering your question, my bearings are .0625" thick and I expect .002 of seating as I work them in. I like a .015" gap on my bearing knives so my pocket needs to be .0625 minus .002 minus .015 which equals .0455". If I'm doing a linerlock, I'd use .0625" Ti and feel confident that when I add my bolsters, I'll have plenty of thickness and strength. If it is a framelock, I also need to account for counterboring a pivot screw. If the head of my screw is .030", I add that to my bore thickness of .0455" and have a total of .0755". Because there is no bolster, the frame will have to provide all the strength. You have to make a call here; how much web do you need between the bearing pocket and the pivot screw counterbore to prevent failure? I would want about .040" minimum to feel comfortable; others may want more. Add that .040" to your total bore depth of .0755 and you get .1155". That would be the minimum thickness I'd feel comfortable with. In the real world, I'd use 1/8" material for the framelock. Hope this helps.

Bob

 

[Cox Workshop]

Great explanation Bob! If you would like a frame of reference I use 1/8 inch titanium for my frame locks, .0625 bearings, mill .023 out of handles and .017 out of blade. You can see video of what that ends up looking like here

https://youtu.be/ItLtZDD-dt8