Trouble with jigged bone scales

D

deloid

Joined
Dec 19, 2007
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458
I mostly make through tang knives as I think of them as the sturdiest. I have made some hidden tangs and I need to get more comfortable with pinning on those.

I have used torx screws on the smaller folder kit knives that I made for practice on the full tang knives and these worked well.

I have been unsuccessful in using jigged bone on a short O1 dagger as a scale. My first attempt was to use epoxy and three pins that were glued not peened. The knife fell once and one slab came loose. I started over again and made the pin holes through the stag slightly oversized and cut a chamfer for the nickel silver pins. I started peening carefully and before the small chamfer was filled the bone cracked on both sides. I used a watchmakers staking set to peen so I wouldn’t have to worry about the bone receiving any blows. I realize now that the pin expanded in the middle and even though I left some extra room it wasn’t enough.

I looked at my old full tang knives and the survivors were shrunken celluloid scales, wood scales and I saw a lot of rivets. The epoxy has excellence adherence but doesn’t do well with shear forces (my opinion) and I cannot believe that simple epoxied pins are enough to prevent these forces.

I only own two vintage bone scale knives and both have cracks at the pins and they also have epoxy failure at the back edge of the knife.

I love the look of jigged bone so any advice would be appreciated.
 
Peening involves flaring the heads of the pins, not the pins themselves.
Use a very small hammer (I use a 1-1/2 oz) and lightly tap the pin heads using wrist action only. Tap around the circumference of the pin, then flat, alternating. You may want to very slightly chamfer the pin holes if you are going to leave the pin heads raised. Chamfer more if you are going to finish flush.
Most bone is oily, and glues don't stick well. Glue is not necessary on a properly pinned knife.
It takes a little practice.
 
Thank you very much Bill,

I didn't know about bone and glue...that explains a lot. It actually also fits with the other knife I mentioned that had epoxy failure. That wood was rosewood, another oily difficult to glue wood.
I like the method you use for peening. That’s what I would have done on a flat surface or a NS bolster with NS pins. The jigging on this scale made me worry since the peening would have to be at different heights (based on the proximity of the gouged out bone).
As I think of this more I could have used I staking tool and slowly and gently turned the edge out. It really didn't need much for the chamfer I had but it did need that lighter more directed touch you mentioned. I also could have used copper pins with a patina to match the scale. This would have been easier (much softer) and it would have still done the job.
Your note was much appreciated. It leads me to rethinking not only this but my whole approach in knife making. I tend to rush the finish with the childish eagerness of seeing the product at completion. Now, after your note and reading some of my art books and samples of art knives I will slow down and test and push my barriers.

Dean Lapinel
 
Thank you. Take a look at [Link Removed]and see what a little patience can do.
Make no mistake, I still lose a scale occasionally.
BTW, you can use a cupped punch to finish your pin heads, or just buff them to smooth them.
 
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Bill is giving some good advice. I learned the hard way about chamfering / countersinking the holes.I cracked or exploded several before I caught on too what Bill is saying. Knowing where to stop with the chamfer is the trick.

I will say this shear force can be one of the hardest to overcome with any epoxy. That is where a pin helps. On some I don't peen the pin. I let the epoxy hold the pin in place and grind flush. I will rough up the center area of the pin and let the dried epoxy hold the pin in place and the pin itself holds against shear force.
I always clean with acetone before final glue up and the last thing I do is re clean this time with alcohol to make sure and hand oils or residue left from the acetone is gone! It dries fairly quickly and leaves no residue behind and you are usually good to go!

When I first started making knives a maker, I like to call my adopted mentor clued me in on how he does a through tang. He uses small holes drilled to the outside edge of the tang and larger ones toward the center of the tang. I also try to make a corresponding hole in the back side of the scales, even a very shallow hole in the scale will work. It acts as internal pin once the epoxy hardens.
And lastly you don't want to squeeze out all the epoxy just enough to get a good closing/bonding of the surface, in other words, "just right"! :D
 
Bill DeShivs said:
Thank you. Take a look at [Link Removed] and see what a little patience can do.
Make no mistake, I still lose a scale occasionally.
BTW, you can use a cupped punch to finish your pin heads, or just buff them to smooth them.
Click to expand...

Bill you must underestimate your stature. I know and admire your work already...had your web page bookmarked already.
Thanks-
 
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While we wait for the real answer from Bill I have made these in the past. buying? No clue.
Options;
O1 rod various sizes, turn in machinest lathe with a ball end mill various sizes.
O1 rod various sizes, find center with graver and round out by hand with a steady rest
O1 rod various sizes, Use center finder then smooth out radius (cup) with hand graver on a steady rest
 
medicevans said:
Dean, not to derail your thread:

Bill, where would a person get a cupped punch?
Click to expand...

If you look a bit you can usually find nail sets large enough or as has already been said make
them. Its what we use to spin a head on our slipjoint folder pins.
Ken.
 
I make mine on my lathe.
[Link Removed] sells cupped burrs in various sizes.
 
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I made mine from a old nail set. Clamped it up in the drill press and cupped it with a bit and polished with a dremmel stone and the HT the point.

But you can buy then off of some of the knife supply sites, look for spinners is what they call them. The dome on the pin looks like it was spun,:eek: I guess!:D
 
Man! I got my pee pee whacked for that one!
I didn't realize that linking to my site in a non-commercial manner was unacceptable- and I apologize.
 
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