Making a Folding knife

[B.Barker]

Ok some have ask about a tutorial on making folders. I'll try to explain how I do it and add some photo's of the process also. This will take me a while to do since I ussually don't have a lot of time to play on the computer. I make two styles for the most part. Both have back springs and were common in the 18th century. I like making the mediterranean style the most but I also make the english style or soldiers knife. I use 1084 carbon steel for the blades and back springs. On the english folder I use wrought iron for the bolster and liner which is made in one piece. For the mediterranean I use mild steel for the liners and brass for the bolsters. Handle material is ussualy horn or bone.

[D. Taylor Sapergia]

I'm looking forward to more on this topic.  Thanks for taking it on.

[Woodbutcher]

 I'm really looking forward to this one! Thank you!   Woodbutcher

[B.Barker]

I'll start with the mediterrean style. I use sheet steel that is about .050" thick for the liners. I also use the same thickness for the brass bolsters. I forge my blade and back springs but you could use stock removal also. I make templates for the blade and handle or liner. I don't make one for the back spring I just use the liner template to get a rough idea. I like to leave quit a bit extra on the back spring. The blade and back spring on my origanal is about .110" and I try to keep mine around this size. Here is a photo of my templates and the origanal the I used for a pattern.

[B.Barker]

Making the blade. I use 1080 carbon steel to make the blade from. This steel forges well and files well when anealed. This knife has a 3-7/8" blade, so I make the rough blank at least 4-1/2". This will leave enough to clamp in the vise and file the blade. The cutting edge is about 3-1/4" and you don't want to clamp this part in the vise edge ways. If you forge the blade out be careful when you taper the blade towards the cutting edge. The part of the blade that the pivot hole will be in needs to have parallel sides. I leave my blade 1/8" at the rear and start my taper towards the tip where the cutting edge will be. After you have the blade in the shape you need, pack the cutting edge of the blade and anneal it. Once it has cooled grind off the scale and start filing the blade. I bring my cutting edge down to 1/32" thick. The shoulder is about 5/32" deep for the back spring. The tail should be a little over 1/2" long. Its hard to give exact measurements because each knife is a little different. After I file my blades out I only polish the part that is back in the liner where the friction will be. The rest of the blade will get a light sanding of 220 or 320. I don't worry about getting all the file marks out. None of the origanals were polished they were filed only, if you look close you can see the file marks in the photo. I hope this is making sense to everyone. If not, let me know what your questions are and I'll try to answer them.

[Ky Ken]

Keep it coming. Thanks Ken

[B.Barker]

Guys it will be a week or so before I post more. I want to forge some parts out to get more photo's. And if everything goes right I'll be picking up more coal on satureday. I'm almost out. So maybe next monday when Hondo and I get back from squirel hunting I'll have some time to forge.

[RobertS]

Thanks so much, this is greatly appreciated!

[Jefferson58]

Great stuff! This is one of my favorite knife styles. Thanks for sharing these techniques.

Jeff

[B.Barker]

I'm back. I was able to gat a blade and back spring forged out this past monday. I'll try to post some photo's the next couple of days. Now that we've worked on the blade lets start on the backspring. File both sides parallel and mark the back with your pattern and file it to shape. The thickness of the spring should be as thick as the blade or just a tad thicker. You don't need to get it spot on you will need to do some adjusting when you assemble the knife. When I go to file the side that rides against the blade I leave it a little taller than my shoulder I filed in the blade also leave the spring longer than you need on the blade end. I'll post photo's to better explain. It's easier for me to show you than tell you. From the blade end back to where the pin will be in the spring I taper it straight. There will be a little hump here when you finnish but you don't want to put it in right away. It's easier to remove metal than add. And a good folding knife should have a strong back spring. Most beginner's, me included make the mistake of making the back spring to weak. I polish the forward side of the spring that will be moving and the part that is between the two pins I don't worry about. My original was not polished at all but I like to cut down on friction as much as possible. Make sure to file length wise on the spring to keep any cracks from starting. Now we can start on the handle. Cut two liners from sheet steel .045"-.055" thick. Mark one of the liners so you can see the outline an awl works well if you have good light and eyes. I use a superfine sharpie myself. Place both liners in a vice togather so you can file both uot at once. This way they will be as close to same as possible also. Take some sheet brass the same thickness as the steel you used for the liners. You need to cut three pieces for each side. You can make patterns for these to make things easy. I use my old knife to get my sizes. The front bolster should be 5/8" long. The middle should be about 1/2" long. The back of this bolter or panel should be cut on a slight angle, bottom wider than the top. The rear bolster should start where the ball intersects with the handle. The original has these bolsters held to the liner with two pins. One is copper the othe is steel and they also hold the knife togather. I like to solder mine as well as using the pins. It holds the brass in place while you drill the holes for a cleaner job. Any soft solder works. You could use epoxy also but soldering is faster to me. After you have the brass bolster in place you can add the bone or horn scales. These are also held in place with copper rivets. The front scale is flat sided with the front and back filed with a bevel. The rear one looks like a triangle if you look at a cross section and the front and back ends are beveled like the front scale. The old ones have designs filed into the scales. Once you have all this done the real fun starts. You can locate the holes for the blade and backspring........

[B.Barker]

Here's a photo of the blade and backspring after being forged and annealed.

[B.Barker]

Top two are knives I made bottom two are originals.

[B.Barker]

Guys I haven't forgot about this project. I've been laying wood flooring, deer hunting a little and getting things togather for a class. Thats just my spare time.

[RobertS]

That's OK, Brian, I'm sure it will be worth waiting for, so don't fret over it.

[B.Barker]

Here's a phot of most of the parts of the knife filed out. I like to leave a hunk of metal at the back of the blade to put in the vise when I'm doing the file work. The blade will be polished a little more where the pivot hole will be but other than that the blade is  polished up ready to cut off the blank. The spring will get more profile work done on it when I get it fitted to the handles. The liners are ready to get the brass bolsters added and the fitting will begin.

[B.Barker]

This project is going slower than I first planned but I'm making progress. I have removed some metal from the back spring so it looks like it has a camel hump now and the blade has the pivot hole drilled. I also put the brass bolsters on one liner. I have put a slight bend in the backspring because they "take a slight set" as Frank House puts it. The spring will loose a small amount of memery and will not have a good strong snap when opening and closing. I hope to get the spring heat treated and fitted to the knife this weekend. I just can't seem to put my rifle away that I'm working on.

[B.Barker]

Here is the photo's of the blade and liner. The pivot hole in the blade is'nt centered. Its a little offset if you don't move it towards the bottom of the blade it makes the backspring stick up past the liners when closed. How much past center, I don't know I'm still playing with the location. Maybe someone else can answer that question.

[mill creek trading]

You do awesome work and I really appreciate your sharing it with us.

[B.Barker]

Guy's I haven't forgotten about the project. I just haven't been able to any work in my shop since Feburary. My mother has been very ill and I have been busy helping my dad take care of her. As soon as things get better I'll finnish this thing up.

[omark]

dont worry about it. just take good care of your mother, she deserves it. best wishes to her.  mark

[B.Barker]

Okay it looks like I may get this thing finnished and have it at the CLA show. It has been so long between post I will probably repeat some things and leave others out. So feel free to ask me to add more details if needed. In this photo you will see that one side of the knife has the bone scales secured to the liner. The old ones used copper as I have. I use electical wire because its soft and putting a rivet head on it is easy. I clamp the bone to the liner with small visegrips while I drill the holes for the rivets. You don't want to use to much presure on the visegrips or you will crack the scales. After I drill one hole I counter sink the scale and the inside of the liner and put the rivet in and lightly peen it with a small hammer. I have a chasing hammer that I use for this. If you use a large hammer be very careful, if you miss the rivet you can crack the bone or if you try to peen the rivet too much. You only need enough to hold the two pieces togather.
 

[B.Barker]

I had to cut the last post short maybe I'll get through this one. At the bottom of the photo you can see the scales sitting under the liner. I leave the scales a little wide and only rough shaped. If you look close you can see that the rear scale has a flat top this is for ease of drilling. The cross section should be a triangle when finnished. I make sure the length is correct and file the finnised angle at each end before installing them. After I have both scales riveted on I trim the top and bottoms then do the final shaping to the scales. I leave the decorative file work on the scales undone until the knife is assembled. The next photo shows the backspring pinned onto the linner. Notice that the spring isn't straight. It needs to ride below the back of the liner when there is no pressure on it. This is the preload of the spring, if you don't have it the knife will not snap open or shut. This one has a little more than a 1/16" on it. The spring itself is complete at this point. Meaning it has been heat treated and poloshed. I finnish the spring befor the blade. I like to assemble the knife and make sure the blade sets properly in the knife liners before it has been hardened and tempered. If the blade hits the back spring you can adjust it easier in the annealed stage.
 

[B.Barker]

I was just looking at one of my earlier photo's on bending the backspring. The arrow should point right in front of the "camel hump", this is where the bend sould be made. I'm going to post two more photo's and add text for them over the weekend. I can't down load photo's fast at home so I do them at work. Gotta get high speed 'net.

[B.Barker]

The top photo in the above post shows the blade with two arrows. These two points will be the contact points when the blade is in the closed posistion. I drew a spring and laid the blade on it to show how it sits in the bottom photo. The teet just behind the cutting edge on the blade can be adjusted to make the blade sit at the height you want, if you leave it long enough. It can be adjusted by removing metal at the bottom corner of the blade. But its best to use the teet. Some of the old knives did not have this protrusion at the bottom of the blade and they hit the "camel hump". When this happens it has a flat spot in the blade where it hits. If you are copying a knife that does not have this teet and you want to stay PC you can prevent the dull spot. Take a small piece of leather and put it at the bottom against the spring this will stop the blade before it hits the spring. I have used this myself to solve the problem. The pivot hole in this blade is 9/16" diameter. I use at least 1/8" for the pivot on the blades because they have a lot of pressure on them. I kept and used my first knife daily for about five years. I cut fan belts, gutted deer, quartered deer and everything between. The blade loosened up a little side to side but still had that snap when it closed. I think if I had used a smaller pivot rivet it would not have held up as well. The rivet for this blade is going to be annealed O-1 tool steel. I haven't used O-1 befor but thought I would try it and see if it holds up better than plain steel. I'm also dropping the blade further in to the knife when its in the closed position. The height that the original is in lets change and keys  slip inbetween the blade and the handle and dulls the blade quicker. Well I think thats covers things so far. I plan on getting more photos and the knife assembled this weekend and finnsh this project for you all. See you later, Brian.

[B.Barker]

I finally finnished this thing up last night. I have several photos to show the progression of finnish work. I heat treated the blade satureday and was able to assemble the knife on monday.  Getting the blade in place is the hardest part of the assembly. I put in the knife last. I have tried to put the blade in and then the spring. However I find the spring first and then the blade works better for me. I rivet the the spring to the liners which is the middle and rear rivets. I then use a extra long rivet for the blade until it just the way it needs to be. I start with at least a 3" rivet and taper one end of it. The taper makes it easier to get it through the three holes. I take the blade, insert it into the handle and make sure it is snug against the spring. Then I set the bottom of the blade on my vise and push down on the handle so the holes line up. This takes quite a bit of pressure to do and you have to be fairly quick or real strong. I make sure I have the front rivet ready to push through as soon as the holes line up. I never get the rivet completly into position but it makes it through both liners and blade. I then hammer it the rest of the way. I use a slow taper so I have about a half inch or more of the rivet hanging out on one side to cut off and then cut off the other side also. The rivet needs to be tight enough to keep the blade from wobbeling but not so tight it won't open and close. I use a small hammer for this job also to prevent getting the blade to tight. Here is how it looks with the blade in.

Once you have the knife togather you can finnish it up. Make sure the backsprin is nice and flush with the liners and clean it up if needed. Now I add my decoration to the scales and bolsters. I use a mill bastard and three square file to do the work. I don't polish all the file marks out of the scales and bolsters. I am trying to recreate an 18th century knife and they never polished this style of knife. If a costomer wanted it polished I would,  it doesn't take long. Here is the knife fitted and filed.

The last two show it with one of my originals. It has had two coats of browning solution on the steel and left overnight. I then cleaned it with a scotch brite. The scales have some "old bones" wiped on them and cold blueing on the bolsters. As you can see the brass still looks to bright. But if it gets carried a couple of months it will mellow out and look better. I will have the knife at the CLA on my table for sale so anyone that comes can stop by and take a look at it. If it's gone by the time you come by you can see mine and take a look at a couple of originals. I hope I have helped someone out with this and feel free to ask questions about the process.