Does Making Quality Folders Require a Surfacing Machine?

Judcargile

Judcargile

Joined
Jul 3, 2022
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139
I have heard that a surface grinder is pretty much a necessity for folding knives. I really think that I am more interested in folding knife designs a great deal more, over fixed.

I have heard that a segmented CBN inserts in a fly cutter can be successfully used to get mirror finishes with a vertical mill; To which, the WEN Mini Mill that I have looked at several times will run about 2500 RPM. IIRC, that will get me into Ti alloy territory.
I would appreciate any recommendations regarding a good mini mill;
I honestly have gone this far thinking that I will cut to the resolution my tools afford and then hand fit from there.
 
I made my first 6 slipjoints with precision ground steel, a hacksaw, a drill press, files, sand paper, and dremel. I think you'd be hard pressed to say a surface grinder is a necessity. I got one this summer, but still don't have it up and running, so I'm up to 26 knives without a surface grinder. Precision ground steel is your friend!
 
Sean Yaw said:
I made my first 6 slipjoints with precision ground steel, a hacksaw, a drill press, files, sand paper, and dremel. I think you'd be hard pressed to say a surface grinder is a necessity. I got one this summer, but still don't have it up and running, so I'm up to 26 knives without a surface grinder. Precision ground steel is your friend!
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Thanks bro, for stock, it would be much easier to deal with, for sure; However, I am primarily tooling up to forge and forge welded pattern and laminate steel. I was planning on using a surfacing attachment for my 72; But, the belts alone seem unlikely to get things particularly well surfaced.
I am ready to do comparative measuring and try for .001 +/-.
 
If doing them from scratch and you want high quality and fit, you will need some sort of surface grinder. You can farm this task out but doing it in-shop is far better.
 
I think there are a number of makers here that use a surface grinding attachment for slipjoint knives successfully. On youtube, there is a multi-part slipjoint build series by Maker's Movement and he uses an SGA as well.

For a mini mill, I can recommend the Precision Matthews 30MV. The only issue I've had with it was the Y-axis lead screw nut coming loose. That was a bit of a pain to fix because you have to get the table out of the way, but not too bad all things considered. I've had it for a few years and it's been very reliable and accurate.
 
I used a 2x72 surface grinder attachment on this damascus steel and got it flat/parallel enough for slipjoints. I think that surface grinder attachments are pretty good at achieving flat/parallel. There is a chance this would be different for non-slipjoints. You don't have to worry about "drop shut" actions for slip joints.
2A1E97BB-D388-43D8-BB2F-8C38C817E15C_1_105_c.jpeg
 
Lorien said:
in the midst of making my first folder, quality to be determined
granite block and sandpaper is my surface grinder for now and things are looking ok-ish so far
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My impression is that a folder needs to be both flat and parallel. I can see how a granite block does flat, but how are you ensuring that it's parallel? (Not being snarky - I really want to know because I want to make folders without buying a surface grinder, so I'm hoping you've solved for this.)
 
If you're making a anything other than friction folders you will need a true surface grinder. Keep an eye out in Craigslist and on govdeals, that's where I got mine. Flat and parallel is an absolute necessity for a quality folder.
 
Tyson A Wright said:
My impression is that a folder needs to be both flat and parallel. I can see how a granite block does flat, but how are you ensuring that it's parallel? (Not being snarky - I really want to know because I want to make folders without buying a surface grinder, so I'm hoping you've solved for this.)
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there are all kinds of height and feeler gauges out there. My height gauge is super basic, but I just find the lowest height and scribe around the circumference with a little dykem and work it down that way if I have to. Most stuff is pretty parallel to start out with
 
Lorien said:
there are all kinds of height and feeler gauges out there. My height gauge is super basic, but I just find the lowest height and scribe around the circumference with a little dykem and work it down that way if I have to. Most stuff is pretty parallel to start out with
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Thanks!
 
Sean Yaw said:
I used a 2x72 surface grinder attachment on this damascus steel and got it flat/parallel enough for slipjoints. I think that surface grinder attachments are pretty good at achieving flat/parallel. There is a chance this would be different for non-slipjoints. You don't have to worry about "drop shut" actions for slip joints.
View attachment 1919017
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Ooooohhh!!!!
 
Lorien said:
there are all kinds of height and feeler gauges out there. My height gauge is super basic, but I just find the lowest height and scribe around the circumference with a little dykem and work it down that way if I have to. Most stuff is pretty parallel to start out with
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I bought a decent height guage and looking at certified inspection blocks, etc. The idea that I will need another multi thousand dollar machine just to dance stinks.
 
I tracked my first belt on my Revolution grinder!!!!
I think I am going to go 200K grit on it and then doodle on it with a graver!!!!!
For portability sake, all of the connections are plug.
Because of cost, each phase is on a 120v cord, end cap plug; I have marked the phase that enables the ground. I have some short jumps in clear tygon tubing for tracking all three phase connections and merely swap A and C phase to run in reverse.
 
Judcargile said:
I bought a decent height guage and looking at certified inspection blocks, etc. The idea that I will need another multi thousand dollar machine just to dance stinks.
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the tools you'd use to check the accuracy of your surface grinder can be used to achieve a flat and parallel surface is what I'm saying. It's definitely time consuming, but I've heard plenty of stories of work coming off the surface grinder being warped and wonky, I imagine from the heat being generated by overly aggressive grinding.

I like the idea of buying precision ground steel, and I do order that with A2 because it's an option. But with some of CPM steels I like, I just can't order them finished like that. Starting to think that the way to go is to bring my steel to a machine shop and have the material decked. It seems to me that milling/cutting material presents less chance of warping than abrading it, but I'm just speculating as I don't have practical experience either way
 
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