Lockback Folder Tutorial

K R Johnson

Well-Known Member
There are two 3/32" pins in my clamping plate that I use to hold the ends of the frames in place so I can line up the scribed bolster lines. The edge of the plate is square with the mill so I can use it to square the lines.


The frames are clamped in place and ready to mill. They are .1920 thick, I want to have .0400 left so I need to remove @ .1500. I do this .0500 each pass with a carbide end mill.


First pass completed, part way through with the second.


The second pass is done and I'm into the last one.




Here I've turned the frames end for end and lined up the bottom bolster lines and re-clamped. Since I'll be cutting in three steps again I've colored the frames with a Sharpie so I can tell when the cutter is the correct height for the final cut.


It's a lousy picture but you can see I'm done.


I scribed lines to grind the bolsters and the frames are pinned together with short roll pins.


I'll take a break from the frames now and grind the blade.


Ground to 600 grit.


To be continued.....again. :)
 

Mark Behnke

Well-Known Member
This is a great education for me and others I'm sure.

When you turn your bushing how do you finish it and to what tolerance?

Milling is new to me so wondering about your clamping plate, could you elaborate on it's design and functions at some point, not sure if we'll see more of it.

Thanks
Mark
 
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K R Johnson

Well-Known Member
This is a great education for me and others I'm sure.

When you turn your bushing how do you finish it and to what tolerance?

Milling is new to me so wondering about your clamping plate, could you elaborate on it's design and functions at some point, not sure if we'll see more of it.

Thanks
Mark
Bronze is easy to turn, just make sure the tool is sharp. When I get close to the finished size I'm usually only taking off .001 at a time and trying the fit between cuts until the blade just slips on. By going slow and taking light cuts, the turned finish is good enough. If it's a little tight I use a tapered 1/8" rod to hold it while I polish a little off with a Scotch-brite wheel. The blade just needs to be able to turn freely on the bushing. The bushing in the blade now is the second one because I dropped the first one and it vanished somewhere in the shop. I finally quit wasting time looking for it and made a new one.

I'll add a picture of the clamping plate. It's an aluminum plate that I clamped to the milling machine table, drilled and tapped a bunch of holes in three rows and milled it flat. It started out flat on the table but I wanted it higher so I raised it up on a base.

I'm glad you're enjoying the tutorial.
 
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K R Johnson

Well-Known Member
Well, here's what the knife looks like assembled. Lock-up is fine so now to fit the scales.



Here's the stag I'll be using.


I mark them on the back side for sawing a little oversize for final fitting. Note: the frame I'm using to mark one scale will actually fit the other scale.


Cut a little oversize for final fitting between the bolsters.


Here's how far in they fit after cleaning up the saw cuts, both of them need more grinding. Go slow, be careful about the angles.


Now they fit between the bolsters.......


.....but they're way too thick Notice I've cut off the excess on both sides.



I've ground off the back sides of the scales. You have to watch the edges because it's easy to got too far, get them too thin and have to start over.



I've drilled the #52 (one step bigger that 1/16") holes for the scale pins............. btw, the other holes are all #41.


Next I glue the scales to the frames. I use Loctite 330 for this, http://usaknifemaker.com/depend-330-by-loctite-250ml-tube-general-purpose.html This stuff is a little spendy but IMHO there's nothing better.


With the scales glued on I can drill the holes through. I have to drill them from the frame side so I use this bar I clamp in the mill vise and clamp the frames to the underside.


 

Brad Lilly

Moderator and Awards Boss
Very impressive! I love the look of the knife and the detail in the WIP is fantastic. Thanks for posting in such great detail
:35::35::35::35::35:
 

jeffsaul

Well-Known Member
Keith,

Really get a completely different impression of what's truly involved in constructing these knives.
Superior photos and wonderful tutorial. One thing I can say for sure I won't be making any knives
for myself, I'll leave this to the pros, such as yourself!!!!!!

Jeff
 

franklin

Well-Known Member
So thats what you have been doing over there in the corner at the hammer inns LOL. That was a nice wip no wonder you want a surface grinder!!!!
 

K R Johnson

Well-Known Member
Well, we have the scales glued on the frames and in's time to install the pins. Here's the way I do it. I use 316 1/16" stainless welding rod and form a head in a heading tool. This idea comes from my blacksmithing background and it's one of the ways heads are formed on rivets. If you make a tool like this you have to drill the hole slightly undersize.


Cut the rod off long enough to hold it in the header, clamp it in and with light blows, upset the head on the rivet.




Next, I use a pin vise and polish the rivet head.


Now I have to make a confession, I forgot to take pictures and I installed all of the pins in the knife handle so..........I'll have to fake it. I'm showing the procedure on some scrap material. I glued a cut-off piece of the stag on a scrap of .030" 401 stainless and drilled a #52 hole.


Using a 1/8" ball end burr and a tapered burr, I chamfer the top of the hole until the pin fits so the top of it is almost flush with the top of the hole.


I also use the tapered burr to chamfer the hole in the liner so it'll hold together when I peen it. Here it is with the pin ready to peen.


I use light blows and a small hammer, and when I can't push the pin when back and forth, I stop peening to avoid cracking the scale..


And sanded off. They don't always hide this well.


Next, I'll be checking every inside surface on the frame, lock bar and blade to be sure it's ready to put the knife together.
 
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jeffsaul

Well-Known Member
Again Keith very informative and extremely interesting, especially if you have any mechanical aptitude.

So many steps that are unseen, great...

Jeff
 

oldknife

Well-Known Member
Keith, very impressive tutorial, have made knives all these years and never made a folder from scratch, bought Peter Fronteddu & Stefan Steigerwald book by Schiffer, on my third prototype may have one that will work for me, it has been a learning experience for me. I think you should make the tutorial into a book it is that good, I would buy one in a heart beat, thanks for posting, has been a great help to me. Deane
 

Lagrange

Well-Known Member
Thanks Keith, you just dont know how much something like this is appreciated. I am looking forward to following this to the end. I feel more confident now and may quite delaying my folder adventure soon.
 

K R Johnson

Well-Known Member
I appreciate all the comments guys! Since there are no questions I'm assuming we'll be seeing more lockbacks in the near future? :)
Once again remember this is the way I do it and not the only way to do it.
 

K R Johnson

Well-Known Member
Let's see if we can finish this up. I've checked all the inside surfaces, hand sanded the blade and etched on my name so we're ready to assemble.

Using the same tapered bur, I chamfer the holes in both the bottom and top bolsters. I ream the holes until the top end of a 7/64" drill bit will just catch in the hole. Since the frames are 416 it's important to use 416 pin stock so the pins won't show. I leave about 1/16" to 3/32" of pin stock sticking out on each side of the knife. It's a good idea to clamp the top end so the frame can't move while peening these pins.


I've peened the pins down until I'm confidant the holes are filled.


I don't stop there, I grind off the domed part of the pin


And peen down the edges of each pin again. It's hateful to have to try to get rid of a pin that's showing just when you think you're done.


Then I grind off the excess and the pins have disappeared.


Now it's time to spin the 316 lockbar pivot pin. I use two tools I've made for this, both are made of 1095 and turned in the lathe and both have a hole in the end made by just drilling the tip of the drill bit into the center.
I made the larger one recently and I need to make another one like it. Both tools are hardened.


One spinning tool is clamped in the vise, the other in the chuck and I line them up and lock the mill table. I've lubricated the top spinner with Vaseline.


I use a fairly slow speed when spinning and check the results often. Alternate from side to side and keep the top spinner lubricated. I didn't get a picture but I countersunk the holes a little with the 1/8" ball and the pins are ground off square on the ends and just a little proud of the sides of the knife. This is something you practice on scraps before trying it on a knife.


Here's a fuzzy picture of the spun head. I'll polish them later. Behind the pin you can see an acorn shield, there's actually one on each side. Look at my previous tutorial to see how to install shields.


The last thing I need to do to complete the construction is peen the blade pivot bolster, again using a 416 pin and the same procedure as I used for the bottom bolster. The only real difference here is that I' have had to make sure the timing mark on the blade and bushing are in their proper locations and I'm peening to tighten frames on the bushing so the bushing is clamped tightly. Again, when I'm satisfied that it's peened tightly and the hole is filled, I can grind off the head of the pin.


Now it's the same as finishing any other knife, it's lots of sanding and inspecting until it shines. That will be soon.
 

Sticks

Well-Known Member
Keith:

Thank you for the great tutorial. I really liked the part on the pins. But, I have a question. I probably overlooked it. Isn't there a piece between the frames at the rear bolsters that is the width of the spring and is where the spring sets? I noticed that you have two holes drilled in the rear bolsters, where a slipjoint would only need one hole to peen the spring. I was wondering if the second hole were to ancher the frame and rear "spacer", before peening both frames together.

Jay
 

K R Johnson

Well-Known Member
Keith:

Thank you for the great tutorial. I really liked the part on the pins. But, I have a question. I probably overlooked it. Isn't there a piece between the frames at the rear bolsters that is the width of the spring and is where the spring sets? I noticed that you have two holes drilled in the rear bolsters, where a slipjoint would only need one hole to peen the spring. I was wondering if the second hole were to ancher the frame and rear "spacer", before peening both frames together.

Jay
Jay you didn't overlook it, I did. There is a spacer that's .001" thicker than the lockbar between the bottom bolsters that looks like this. The spring sits on the 'shelf' and the pins go through the holes. I'm sorry I missed that and maybe I can remedy it when I build another.
 

Sticks

Well-Known Member
Thanks. Keith. I'm still messing with slipjoints but want to try one of these soon and I'll follow your tutorial.
 
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