Observation from Boker knives

R

Randy3000

Joined
Jun 3, 2017
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I haven't posted here in a while. I have been busy making half whittlers which is my speciality. I will make any blade profiles people want though. But I made the journey to the slipjoint knife mecca today, Smoky Mountain Knife Works in Tennessee, and bought a Case half whittler and a specimen from Boker with a clip point main blade. This is the pattern with a single backspring and 2 blades that pivot on either end with the main blade full thickness and the small pen blade thinner with an extra piece of liner to make up the thickness. If there is a name for this pattern with clip point main blade and pen secondary blade, please tell me because it is a common request and I just still call it a half whittler.

What struck me upon opening the Boker was the backspring was struck while it was hot to deform the metal exactly where the blade tangs make contact. The blade tang notches were also similarly struck. This fascinated me because it reduces the filing time needed to fit the blades and spring together, and I have never noticed this technique used by any other maker. It also makes it possible to cut blank springs and blades in bulk and fit them with very little profile grinding, because you are deforming the metal in the key fitting areas and the rest stays the same.

My question is if this forum believes this extra step of heating up the parts and striking them before the heat treating step causes any undue stress to the parts? Is warping more likely? Is normalizing needed? I want to try this method if it reduces production time, but only if quality is not impacted.

I do my own heat treating starting from 02 from Amtek. I normally just stock remove and heat treat as is. A nice member here tested some coupons for me and my heat treat is optimal for this steel. I would like to keep it that way.
 
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This is the Boker knife I bought, they call it a "pen knife stag"
https://www.bokerusa.com/pen-knife-stag-118288hh
boeker-manufaktur-solingen-pen-knife-stag-118288hh.jpg
 
By the way, for the record, I was highly impressed with Boker knives. I can pull 9 out of 10 Case knives from the shelf and find defects I wouldn't let pass. But I was just really impressed with all the Boker specimens I saw. I would have earned $2 an hour from that Boker knife if I sold it for what I paid. It made me really reevaluate my methods. I think every slipjoint knife maker should spend some time at SMKW looking at Boker knives. It will make you want to improve.
 
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Can you show a picture of what you're talking about? I think I have an idea, but I want to be sure.
 
I cannot get a good picture of this on my knife due to lighting and crap camera. I ripped a template drawing off the web and circled some places. Boker for sure does this on the spring, and possibly on the blade tang in 1 or 2 places. Basically you would heat up the parts, lay them on their side, and strike near the edge (strike perpendicular to the computer screen) while hot to deform the metal and make a little bump. The bump would deform the metal down for the spring, up at the tang notch, and down at the tang kick. The deformation is one sided. When I open the blades up and look into the knife, you can clearly see the spring has been dented like this. It appears the blade tang has been too at the places I circled, but much of the bump had to of been filed off, so it is hard to say for sure. But the spring bumps are plain as day.

KLAxIsN.png


It is possible they just do this to the spring, and the purpose is reduce the tang kick. Maybe saves a little material?
 
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I have Rough Riders slip joints that have the spring "punched" where the tang hits it.

Not really a quality way of making a custom knife
 
AVigil said:
I have Rough Riders slip joints that have the spring "punched" where the tang hits it.

Not really a quality way of making a custom knife
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What specifically is undesirable? Besides the fact you can see it. There are many things makers do that i think are horrendous, such as bending blades.
 
As a maker of slipjoint blades that is totally unnecessary to do. If you want extra material there then simply leave extra material while grinding.

It has the appearance of correcting a mistake due to poor planning, it will form a big stress riser there and if the spring breaks it will be at that spot.

As for bending a blade, krinking blades is traditional and allows for the most blades in the least amount of space and actually requires skill to do well.
 
Ah, I see. Yeah, I wouldn’t bother. I don’t really see how you’d be any more consistent, or still not need to spend time dialing it in.

Lately, I cut my tang notch with a shallow dovetail cutter so that instead of 90 degrees it’s more like 75. This does the same thing, with two points of contact, and is much more precise.
 
Drew Riley said:
Ah, I see. Yeah, I wouldn’t bother. I don’t really see how you’d be any more consistent, or still not need to spend time dialing it in.

Lately, I cut my tang notch with a shallow dovetail cutter so that instead of 90 degrees it’s more like 75. This does the same thing, with two points of contact, and is much more precise.
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I have an extra 240 plug in my garage shop, one day i will get a good mill. I quit doing 90 degree notches awhile back. I cant stand any play in the blade when it is open. Doing the sub 90 degree notch eliminates that play completely. I do everything with a portaband set up on my bench like a bandsaw, a benchtop drill press, a 1hp grinder i built, a buffer, disk sander, 2 heat treat ovens i built, and a flex shaft.

I spend a day cutting out, profile grinding, and heat treating springs. I usually get 6 to 8 done that day. Then i make one knife at a time. I spend one day sanding the spring to 60 grit, cutting out and fitting the blades to the spring, grinding bevels on the blades, and heat treating the blades. Then i spend a day rough sanding the blades to 60 grit, cutting and soldering bolsters, rough profiling the liners and bolsters, and gluing and pinning the handle material. Then i spend another day finish sanding, buffing, assembling, and sharpening. I use stag a lot and dont do shields on stag. If i use any other material i will do a shield and that takes a half day. I dont use precut shields, i hand file all shields from scrap bolster material and make wacky asymmetrical designs, it is my signature. Stag is awesome and i wouldnt dare try to gussy up natural beauty like that. So it takes me about 30 hours per knife. Is that typical? I have 2 kids now so it is challenging to get time like i used to. I am thinking about waterjet cutting aeb-l and outsourcing heat treat to save time. A lot of people like stainless. i dont care for stainless but a lot of people do. I have had complaints about my O2 blades being too hard to sharpen, but these people always seem to really F up the edge doing some extreme low angle and sharpening deep into the primary bevel.
 
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Nothing like a perfect fit with little work. Worth trying if you ask me.

If you are worried about warping you can always use a stress relieving step, many steels are 1200 degrees for an hour and then slow cool in oven to 800 degrees followed by air cool.
 
Randy3000 said:
I have an extra 240 plug in my garage shop, one day i will get a good mill. I quit doing 90 degree notches awhile back. I cant stand any play in the blade when it is open. Doing the sub 90 degree notch eliminates that play completely. I do everything with a portaband set up on my bench like a bandsaw, a benchtop drill press, a 1hp grinder i built, a buffer, disk sander, 2 heat treat ovens i built, and a flex shaft.

I spend a day cutting out, profile grinding, and heat treating springs. I usually get 6 to 8 done that day. Then i make one knife at a time. I spend one day sanding the spring to 60 grit, cutting out and fitting the blades to the spring, grinding bevels on the blades, and heat treating the blades. Then i spend a day rough sanding the blades to 60 grit, cutting and soldering bolsters, rough profiling the liners and bolsters, and gluing and pinning the handle material. Then i spend another day finish sanding, buffing, assembling, and sharpening. I use stag a lot and dont do shields on stag. If i use any other material i will do a shield and that takes a half day. I dont use precut shields, i hand file all shields from scrap bolster material and make wacky asymmetrical designs, it is my signature. Stag is awesome and i wouldnt dare try to gussy up natural beauty like that. So it takes me about 30 hours per knife. Is that typical? I have 2 kids now so it is challenging to get time like i used to. I am thinking about waterjet cutting aeb-l and outsourcing heat treat to save time. A lot of people like stainless. i dont care for stainless but a lot of people do. I have had complaints about my O2 blades being too hard to sharpen, but these people always seem to really F up the edge doing some extreme low angle and sharpening deep into the primary bevel.
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I lose track of the hours after a couple of weeks. Hahah. It’s not that it takes me so long, but I have 4 kids and 1000 other things going on. ;)

How about wire edm with pre-hardened stock?
 
Drew Riley said:
I lose track of the hours after a couple of weeks. Hahah. It’s not that it takes me so long, but I have 4 kids and 1000 other things going on. ;)

How about wire edm with pre-hardened stock?
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Never heard of wire edm, I will look into it. I guess it is time I outsource some work. I actually work for a company that makes CAD software, so I got that part covered covered haha. I can actually lay my templates on a paper scanner, scan them, edit the scans to clean them up, bring them into the 2d drawing product and create the file.

I wonder about liners too. It would be neat to have liners made in bulk with holes already drilled.
 
Wire EDM is most likely going to be more expensive than waterjet or laser, but it’s two main advantages are precision (+/- .0001), and you can cut hardened tool steels (which actually makes for better cuts). The finish off the machine will be cleaner as well, vs other methods. The biggest problem is that it takes the longest to get those cuts, and that adds to the price.
I’ve never had it done or really looked much farther into it, but it may be worth exploring.
 
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