Shadow Pattern Slipjoint Question

David Schott

David Schott

Joined
Sep 27, 2004
Messages
3,041
Hello,
When constructing a shadow pattern slipjoint with a bushing pivot, do I really need to add a washer to peen the pivot pin into, or can I just peen the pin directly into the scales?

The washer construction looks like a traditional sodbuster, where a 1/4" or so washer is put into the scales, then the pin is peened into that.

The way I see it, if I am using a bushing, the liners themselves squish the bushing and the blade revolves around the bushing. This should mean that hardly any pressure is exerted on the pivot pin itself.

I made a shadow construction just peening the pin directly into the scales without a washer and it had held up just fine....

Is the washer construction really necessary or is it just tradition? I assumed it was done mainly to allow stronger peening of the pin and to avoid cracking the scales since theres no bolster to peen into....

Any thoughts here?

For reference, this is the washer construction I am talking about:
5_63802.jpg
 
I make shadows both ways. If using G10, for example, I think just an 1/8" pin is OK because the materials is so hard. If using softer micarta...canvas, for example, I use a 1/8" washer of varying diameters with the pin. have built shadows using micarta and just a pin and have had no problems.....but for the sake of longevity and my piece of mind...I use a thick washer...actually a stainless rod bored thru the center and cut to whatever length I need. I think if you are using jigged bone, ivory, etc. a washer is needed to spread out the load and to prevent splitting.
 
I think John pretty much summed it up. On the one I just posted I could have just gone with the pivot pin and all would have been good(g 10) but again,, peace of mind, traditional appearance I went with the thick washer. In this case .250 dia.

Good luck on your builds,

Ken
 
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Even in softer materials, the washer isn't necessary. It's just a different way of pinning, instead of hitting the top of the pin, you gently hammer around it. I made a sketch:
rivettage.jpg


Cause if you hit on wood like you hit on G10, the head of the pin will expand too much and fracutre the wood. By hitting only the corners of the pin, you just pinch the scales lightly, but that's enough for a slipjoint. Learning to pin/rivet is a basis in french traditionnal knifemaking (a nice example here).
 
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PERFECT guys! Thats just what I wanted to hear and I am glad my mind thought this one out correctly. The more I thought about it, the less I could picture the need for reinforcement for other than protecting the scales/tradition/piece of mind.

I'll throw up some pics of this knife once I get home today.
 
I don't believe I agree with Magnum on this issue. The softer the material...the more sq inches or area you need to achieve success. Now success may be 10 yrs from now..not necessarily tomorrow. Look at all the great 100 yr old knives still working well. This is the durability you are after. You just do not achieve this with soft materials over a long period of time without a larger area of compression.
 
FWIW...lots of very old slip joints don't have washers and a good percentage of them have wobbly blades BECAUSE you can't pein the pin as tightly. Washers=good(er).
 
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