slipjoint: peening

S

stezann

Joined
Apr 13, 2011
Messages
1,914
Hi slippie makers!
I have a couple of question regarding the peening of the stainless pins (hammering, not spinning). I'm trying to get better at it.

1) pivot: what shape on the ends of the pins before starting peening? is it better a little domed, dead flat, or hollowed (to help spreading vs. upsetting and freezing the blade)? (i can't use a bushing due to the small dimension of the tang); the pin in the end has to disappear in the bolsters.

2) handle slope issue: if the scales are not flat in the area of the center and back pins, but are instead kind of contoured (kind of elongated egg-shape seen from the spring side), so the pin holes lie on a slope, how to manage the peening in order not to have the pin bent?
Do yo think it would be a good enough procedure to ream 10° straight square and peen straight down, or there is some useful trick to manage this one?

Thank you for your kind reply

Stefano
 
I keep the ends of my pins dead flat, and don't worry about any angle. I use a small hammer and try to go around the pin hitting the edge more than the center (I try not sure how successful). The 10 degree should be ok. Take your time and watch how the pins mushroom on each side. I also have a hard steel bar about 3/8 thick slightly rounded that I place in a big vice to rest the bottom of the pin on, a few hits on one side and change to the other side.
 
I use a small tapered pin reamer that is appropriately sized for the diameter pin I'm working with, keep my ends flat, and use the smallest hammer I have (a small finishing tack hammer) to peen the ends of the pin.

I have a short bolt (about 1.5" long, 1.25" diameter hex head, IIRC) that I ground the top smooth on and use as my peening anvil. The material the bolt is made out of is much harder than the brass or stainless pins I typically peen, so it doesn't appear to be wearing really at all. I just chuck it into my bench vise when I'm peening, and it works much better than the "soft" anvil that the vise came with.

After peening the pins so that they expand and fill the reamed portion of the hole, I typically just grind everything flush and they shape the handle.

As long as you don't remove much or any of the pin past the original handle/scale face, you shouldn't have any issues compromising the strength of the peened pin.

I neat little test I've done in the past is making a "scrap sandwich" and pinning the pieces together as I would normally install and peen a pin. Once everything is finished as normal, try to pull the pieces apart. It may not seem like you're leaving a lot of pin to hold the pieces, once everything is ground flush, but the pieces are (or should be) extremely difficult to get apart again.
 
Thanks for the replies guys!!
Tipically as an anvil i use a very large ball bearing ball which will fit well resting on the hardie hole of my forging anvil; it is very hard and the result is almost like i'm hammering from both sides as once. Nevertheless i often swich side.
I think one of the difficulty (for me) is avoiding the pins bending while peening (the most if the hole lies on a sloped end of the scale), but next time i'll shape the pin ends dead flat, and i hope it will help. If the ends are domed, the force of the hammer will try to bend the pin from the beginning, and probably that was what i was doing wrong.
The scrap sandwich idea is nice, i will try it and will use it also to pratice with hollowed pin ends; my idea is that if i peen an hollowed head with a flat or slightly domed hammer there will be more bias against upsetting and more tendency to an even spread. At least will be free pratice ;)
This thread is not closed, and if anybody will like to share their peening tips will be very appreciated :)

Stefano
 
If your pin bends it's too long and you are hitting it too hard.
 
Bill DeShivs said:
If your pin bends it's too long and you are hitting it too hard.
Click to expand...
Bill beat me to it. He's the man of peening! You ought to see his hand peening videos!

They rival anything Nick Wheeler does..........


All good natured gentlemen, put down the sticks!
 
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