Case sodbuster blade play revisited

[Planterz]

I only ever bought one Case sodbuster, a Jr. in yellow delirin and CV. The blade wobbled like a Weeble in an earthquake. No amount of whacking the pivot with a rubber mallet could help it even a little. I know sodbusters are meant as cheap working knives, and I didn't spend much, but it was still very disappointing. I don't much care for the sodbuster blade anyway; I prefer a pointier tip and little belly. The knife is a hunk of rust somewhere in a box of junk.

 

[Obsessed with Edges]

Whichever device or method (vise or mallet) is used to squeeze the pivot, it'll work much better if the surfaces exerting the squeezing pressure are firm/hard enough to NOT deflect or deform around the head of the rivet. I think when I first tried to tighten my Soddie up a bit, I'd tried a somewhat softish-headed mallet (rubber on one end of the mallet head, plastic on the other). Rivet didn't move much, trying that. Finally figured out the 'shock absorber' effect of the mallet's softish face was dampening the impact too much, so the rivet wasn't moving. That's when I tried my Pana-Vise instead, which has fairly firm/hard nylon inserts in the jaws, and was robust enough to make the rivet squeeze together.

 

[Tim Schneider]

Separating the rivet sounds plausible, but I have only drilled and that works. Clamp in vise to drift the center pin, it is snug. Plan to use new pin material to replace.
There are of course 2 different 2138 models. The old pre 90 has a thicker blade and spring, making the handle wider, it is more robust than the newer post 90. The late models have a deeper blade belly and more narrow spine and spring, not as hefty but a better kitchen slicer, akin to a substantial paring knife. My first disassembly was an old model in pristine condition but a very weak spring. Case would not fix it, so I decided to take it apart. I surmised that it must've spent its life half opened in a display case.
The old models have a rear pin that is captive in the spring, but newer design pin is not captive and the spring lifts out with only the center pin removed. It is not necessary to replace the pivot when performing the spring re-arch.
As Obsessed mentioned, Vise is best way to tighten the existing cutler rivet.
If replaceing pivot, old models need a 1/2 long barrel, new models need a 3/8 long barrel. The pivot screws will sit nicely down in the pre-existing scale countersinks.

 

[KHarper]

I only ever bought one Case sodbuster, a Jr. in yellow delirin and CV. The blade wobbled like a Weeble in an earthquake. No amount of whacking the pivot with a rubber mallet could help it even a little. I know sodbusters are meant as cheap working knives, and I didn't spend much, but it was still very disappointing. I don't much care for the sodbuster blade anyway; I prefer a pointier tip and little belly. The knife is a hunk of rust somewhere in a box of junk.

Like Obsessed says, I also found the rubber mallet didn't work. I was a little worried about the nice new brass and the handle scales, and so I tried the rubber mallet. 5-6 hard whacks didn't do anything. I decided to try the good old steel hammer before I tried the vice, just being careful to hit dead on the rivet, and I used a newspaper to protect the knife. It tightened right up in a couple moderate raps. So I agree with obsessed that our anecdotal evidence suggests that soft hammers don't work. If you don't want to try to fix your sodbuster up, you can send it to me and I'll give it a whack (pun intended?)
I think he's right, it spreads the force of the impact out over too long a period, and allows the natural flexion of the metal to absorb the force without exceeding the threshold required to drive the pivot sections into each other further; it looks like the female half has to actual deform around the male, creating a tight friction fit. That takes a fair threshold of force to do, and woth a soft hammer, while the total force may be the same, it never peaks high enough to reach that level. A vice can do it even though it's slower because it can exert a higher total force, and sustain it as well. I think unless you find a really heavy rubber mallet it won't be enough.
I thought physics was a fascinating class; I hear it gets really abstract and boring when you get beyond the basic levels, but High School physics covers a lot of really cool stuff, and basically explains how everything works.