Learning how to make slip joint folders

[KnifeHead]

Tony Bose has been gracious and extremely patient enough to let me learn from him in our spare time. I get over to the Wilfred Works whenever I can. I had Veterans Day(Nov 10)off from work and started this Damascus "Backpocket", he calls it. The Backpocket is one of his own design as most of the knives Tony makes are from old patterns that he "brings back from the grave".

Tony suggested that I grind this blade on his 14" wheel as my grinder only has a 10" wheel right now. I ground the edge bevels, after some help from Tony on one side. After the rough grind, Tony stress relieved it.

I ordered a stamp from Harper Mfg.(great service!) When the stamp came I went over one evening and stamped the blade last week and got it ready for HT, which Tony did. Tony uses a 3/16" bushing as a pivot on his folders and he lapped the bushing in for me. The bushing is about .001" wider than the blade which allows the liners to compress against it rather than the blade.

Last Saturday morning I ground the edge bevels with Tony looking over my shoulder for a bit. I'm starting to like that 14" wheel. Rather than take the chance on horkin up the nice blade, I asked Tony to grind the swages. Tony says, "Grindin' swages aren't for the faint of heart". That is a fact!

I have tinkered with the action between spring and blade and can work on the liner/bolster assy's now. Notice this isn't a cam-end blade as it is flat and produces a detent position at mid-open. That means the spring has to be dead flat with the liners and blade in all three positions. I'll be re-etching the spots that were ground during adjustment.

Bose Knives commonly have 410 SS for liners and bolsters and that is what I am using on this knife. Tony is going to show me "an old indian trick" for soldering them together. I actually took the bait on that one.(I am gullable enough to believe everything he tells me 'cause I don't know squat).

Anywho, here are some pics of the progress with my first folder project. I'm learning alot and have to thank Tony for being so patient with me.

 

[David Wesner]

Lookin good Kerry :thumbup: Consider yourself very,very lucky to have a mentor close to home . Shortens the learning curve immensely . Is that your new stamp just above the pivot hole ? I really like the idea of the stamp verses etch of touchmark.

 

[KnifeHead]

Lookin good Kerry :thumbup: Consider yourself very,very lucky to have a mentor close to home . Shortens the learning curve immensely . Is that your new stamp just above the pivot hole ? I really like the idea of the stamp verses etch of touchmark.

Yep..that's it. The button in the bottom left corner of the pics is the stamped section copy/pasted/enhanced. Tony says you should put your name on there because no one will know who it is that made the knife 100 years from now if you use your initials or a symbol for a logo.

 

[Michael J. Spangler]

nice stuff man keep us posted and let us know when you have some for sale.
what do you plan on using for handle materials? good job man

 

[fitzo]

Nice start to what will be a beautiful knife.

You are somewhat advantageously located if one is seeking instruction from a friendly world class slipjoint maker. I'm sure others here share in my envy.

I hope you will continue posting an "in progress" journal of your project. Thanks for sharing!

 

[Don Hanson III]

You are learning from the best slip joint maker in the world, I have one of his large "Back pockets" in ivory and a very fine knife it is.

 

[KnifeHead]

nice stuff man keep us posted and let us know when you have some for sale.
what do you plan on using for handle materials? good job man

I've been lookin at the Turnage mammoth ivory on Ebay. It needs to be either that or some premium stag.

 

[KnifeHead]

Nice start to what will be a beautiful knife.

You are somewhat advantageously located if one is seeking instruction from a friendly world class slipjoint maker. I'm sure others here share in my envy.

I hope you will continue posting an "in progress" journal of your project. Thanks for sharing!

Thanks Mike. I don't take this opportunity lightly and I soak up everything I can learn from him. I'll just add to this thread as I get further along.

 

[holmsy]

there is obviously a pin that goes through the centre of the bushing, does the bushing rotate on the pin and stay fixed in the blade, or does the bushing stay fixed to the pin and the blade rotates on the bushing?

brett

 

[KnifeHead]

there is obviously a pin that goes through the centre of the bushing, does the bushing rotate on the pin and stay fixed in the blade, or does the bushing stay fixed to the pin and the blade rotates on the bushing?

brett

The blade needs to rotate on a stationary bushing. In fact, if the bushing were to rotate, it could cause you fits due to a potential out-of-center hole in the bushing. So, extra measures are taken to make sure the bushing doesn't rotate. A "timing mark" is placed on the bushing to insure it is in the same place throughout the adjustment phase and final assembly.

If you have ever used a T Bose knife and felt the slip joint action and compare that to pin-only slip joints you would feel the difference. It is very smooth and there is very little side pressure on the blade from the liners.

A Certain knife company tested the spring pressure on one of Tony's knives and compared that to a similar production knife they had made. They were trying to figure out why they were having a few broken springs. It turned out that the spring pressure on the Bose knife was less than the production knife. They figured it was due to side pressure from the liners and they were having to load the spring pressure higher to get the knife to work properly.

It takes more planning and thought to use bushings in a slipjoint but it makes a difference in how the knife works.

 

[Saberman]

Wow Kerry, looks like your doing a great job. I know it doesn't hurt to have a great teacher.

Also, I wanted to that you for your description of what, how, and why things are happening. You've done a great job communtacting the process.

 

[KnifeHead]

Last Saturday, I showed up at the Wilfred Works about an hour before Tony and I went to a little knife swap in Coal City, IN., about a 45 minute drive. Talk about stepping back into the 40's. It was held in a little old time grocery with creaky wood floors and there were many fine old knives that were there to be bought or traded.

Anyway, before we left, Tony layed out what I needed to do next with the Backpocket knife. I watched as Tony prepared the pins I would be using to layout and assemble the knife. I layed them all out on a paper towel and labeled with a sharpie and snapped this pic to post here in the forum.

At the top is the liner material, 410 SS. It is stronger than nickel silver and more resistant to cracking at the pin holes. Tony likes using it and says it finishes better than NS and the finish holds up much better. 410 is also used for the bolsters and you'll see that a 410 3/32 pin is used for the pivot. It's harder and better to use for the pivot. Also, the 410 pin will match the 410 bolster when peened. A 3/32 hole is drilled for this pin in the liners.

At the right of the 410 pins are the middle and end pins made of 316 SS. Tony uses 316 because it is easy to either peen or spin a dome on. The middle pin is the spring pin that takes all the tension. Notice it has a very long taper to aid in lining up the holes as it is driven home. The spring is tensioned about a 1/3rd of the width of the center hole and that is then used to spot the hole in the liner. The middle and end holes are drilled with a #41 drill bit, which is slightly bigger than 3/32. 3/32 pins slip right in.

In the upper left corner is a drill rod that has been tapered and flats ground on both sides. This is used in the center hole when fine tuning the knife. We'll put it together, take it apart, put it together, etc. many times and Tony says that if you use a non-hardened pin it will literally grind the center spring hole and affect the alignment. The flats are put there to make it easier to hold on to with visegrips. Again, the long taper is there to aid in bringing that spring into position.

 

[John L]

Kerry: How are the holes in the liners and bolsters reamed? Are they tapered for peining and if so, how much? As a person who doesn't know much about folders, how is the SS bolsters soldered to the SS liner? What is flux and solder? When the blade is etched are wear areas left unetched so that the varying layers of steel do not rub on spring? When peining on fragile scales...MOP for example, are the scales simply glued on and then false pins inlayed? So many questions...so little known...by me. Anyone, please answer any or all questions along with Kerry.

 

[KnifeHead]

John L, at this stage, there is only holes being drilled in the liners. I'll be posting more about that as I go along with this project. The first hole drilled is the pivot pin hole. The liner is placed on a piece of pine 2x4 or 2x6 and the blade is "nailed" onto liner into the wood. Now you can pivot the blade around. Then, the spring is positioned on the liner in the correct place that looks about right in alignement with the blade. The end spring hole is then marked and drilled and nailed into postion. The spring is then compressed about 1/32" and the hole position marked with a transfer punch. Transfer punch is a center punch that is the same size as the hole you are marking.

Now you can drill the middle hole in the liner, compress the spring and nail that to the jig and work the knife. Before you nail that compressed spring to the jig, you can make a mark along the top of the spring on the board and work the knife between all 3 positions. The goal is the spring should be in the same place in all positions.

Soldering bolsters will come later but basically you pre-tin the bolster and liners before putting them together. Tony uses what amounts to Stay-Brite solder and Stay-Clean flux.

Bolster holes (Pivot Pin holes) are tapered with a 10 deg. reamer down about .040". Don't go too deep with that because you would be asking the material to do more than you should ask it to do to peen it out more than that.

Doesn't matter what handle material is used, everything is pinned and peened. Tony uses a gap filling super glue to hold the handle material on while working it but the pins are what is need to really hold the handles on. 2 deg. tapers are reamed in the handle material for the pins holes that go thru all layers so that the pressure is on the liners and NOT the handle material.

Wear on the blade is minimized by end milling .007" deep relief on the inside of the liners in the pivot area. The only part of the tang that rubs the liners is about a 3/8" spot around the pivot and that part won't see the light of day.

 

[joe9knives]

hurry up a get done. i really can't wait. looks really great so far.

 

[John L]

Thanks Kerry. This has been the most interesting thread for me in a long time. John Lloyd

 

[Michael J. Spangler]

kerry turnage has really nice stuff like you said but if you're thinking of pearl at any point go with AUI.ORG they're a great company to deal with.

 

[KnifeHead]

Thanks for the comments Joe, John, and Mike. I spent Wed and Thur with Tony and took lots of pics while watching him finish up a Backpocket in Ivory. I will post more pics and text after I get back to work on a broadband connection but here is his finished knife:

 

[Michael J. Spangler]

man thats ugly.... send it to me i'll dispose of it.
gotta make sure its done properly.

so when are you gonna start selling some?:thumbup:
nice knife man he did one heck of a job. looks like you got a chance to learn from someone who really knows what he's doing.

 

[KnifeHead]

man thats ugly.... send it to me i'll dispose of it.

Oh yea, don't I know it. It was all I could do to take the pic... it's so dang ugly.

This knife is going to be engraved(not sure by who) and will be at the Blade show.