Friction folder build-along

I've had a small piece of 1/8 O1 laying on my workbench for some time now. Since we're facing a cool, wet weekend here, I figured it was time to turn that bit of steel into something useful. I decided to have a go at making a friction folder. I've never made one before and I figured, "How hard can it be?" So if you're interested, follow along and we'll find out.


This is my starting point, a piece of 1/8" O1 about 4 1/2" long by 2" wide. Not a lot of room for error. I made a few sketches, adjusting here and there until I could fit the pieces into the space I had, with room to cut them out.

I covered the piece with black marker and scribed out the design. A little quality time with the hacksaw and I have the rough cutouts. I used a center punch to mark where I need to drill for pins and pivot.

To be continued...

 

Re: Weekend project

The project continues.

I spent a couple hours today with the files, shaping the blade and back. It came out pretty close to the design I scratched out.

After filing and drilling.


And once I cleaned things up a bit, it almost looks like it's going to be a knife.


Next installment: time to move to the grinder....

 

Re: Weekend project

Last night I did the rough grind on the blade -- and I do mean rough. I probably should have noticed that I had a 36 grit belt on the grinder, but I didn't. I usually grind small blades with a 60 to start and then finish by hand, but this did the job.




I ran the blade through the grinder a few more times with progressively finer belts to get smooth things out and then finished off with some hand sanding. It came out pretty much ready for baking.




While I was at it, I cut out a couple of liners. I know that liners aren't really needed on a friction folder, but I wanted to add some thickness to the handle, and I think titanium will wear better over time.



So all the bits are done. All that's left is to heat-treat and do the final clean up and assembly. I'm using a simple white paper micarta for the scales (they're under the liners in the photo.)

 

Re: Weekend project

This turned into a two weekend project. I got busy and couldn't get to heat-treating until this weekend. It came through just fine and after a bit of clean-up, I put it together. I'm pretty happy with the way it looks and works. There's just enough "friction" to keep the blade closed but not so much as to make it feel stiff. It feels quite nice in the hand too. I didn't clean up the blade completely; I thought it looked a little more rugged that way.

Here's the specs on how it came out:
Length (open): 16.5cm (6 1/2")
Length (closed): 10.5cm (4 1/8")
Blade (tip to the handle) 7cm (2 3/4")










That's it for the Weekend project. I hope you enjoyed the process as much as I did. If you've never made one of these before, give it a try. They're a lot of fun to build.

 

Re: Weekend project

Thanks. Nice to know somebody's looking at this stuff.

A friction folder has no spring or locking mechanism to hold it open or closed. It stays closed by the force of pressure on the blade between the scales. That's determined by how tight you peen the pivot pin (or how tight you turn the screws in a screw-type pivot pin.) It has that long tail at the top of the tang that you put your thumb over when it's opened so it's just your grip that holds the blade in the open position. There's also often a stop pin inside that limits how far the blade can open which lets you apply more pressure in cutting. In my case, I milled a notch in the tang and extended the back spacer so they meet. You can also incorporate a kind of saddle that swings down to clip over the scales as well. Lots of options to play with.

Other folding knives use springs, locks, detent balls, or some other mechanical means to keep them open and closed.

Hope that makes sense.

 

There's just something about friction folders. The concept is simple and they just work so well.