You use a lot of epoxy

It’s the right hammer for a surprising number of problems; if I never want to take it apart, there’s no reason to bother with fasteners! Of course, that same logic annoys me no end when it’s applied to consumer electronics…

I save plastic lids from raisin canisters and suchlike specifically for mixing epoxy: broad, flat, shallow, easy to smoosh the resin and hardener into a uniform mass. The house came with a supply of thin wooden sticks that are perfect for mixing epoxy; I have no idea where to get more of them, though.

enveloping them in a Sugru wad

That should work fine!

Mostly, you just need something to protect the wires and hold the plugs in place; there’s no real strength involved. Epoxy putty is fairly strong, even if it’s not in the same class as JB Weld, and has the key advantage of not dripping.

Mixing putty is dead simple: just cut a length from the rod and knead it together. Alas, my putty stock is aging out: the outer layer has formed a brittle skin. Still works …

You use a lot of epoxy — you obviously have the knack for mixing it right, which somehow I’ve never managed to pick up. But rereading your older post makes me wonder about jamming the plugs into the jacks and enveloping them in a Sugru wad rather than epoxy. I think it’d have enough give to allow you to extract the plugs. The question is whether it’s too soft to provide the protection you need.

a measurement of two loose pins in the jacks

I ran into several problems while I sat there at the bench, poking things into the radio and wondering what to do. [grin]

• The jacks apply an asymmetric force to the plugs, so the plugs don’t emerge perpendicular to the radio and don’t lie parallel to each other.
• The jacks lie in a recess that makes it impossible to measure down where it really counts.
• The jacks lie under a rubber gasket with snug-fitting holes, so I’d probably be measuring the gasket rather than the jacks.

The first problem burned me badly on an earlier iteration of this project with an ICOM Z1A radio: I firmly wedged a pair of plugs into the radio and had to break up the epoxy blob to extract them. Now I make alignment plates and gluing fixtures and I don’t have that problem any more. [sigh]

Anyhow, I figured I’d just space my plugs the way the Big Boys do, but it’s not clear they all do the same thing…