Have you seen what the proper T&B dies for this sort of application look like?
They are *not* just your cheap crimper scaled up-- the barrel of the lug is *swaged* down on the leadwire with interleaved fingers on the die set, not just collapsed inward in a small section. That's why they don't come loose.
Yes, I've seen them, and I've done a lot of it for electrical and weight-bearing equipment -- both with the right Thomas & Betts and AMP crimpers and with makeshift tools. You can make up in technique a lot of what the right tool would do automatically. Crimps aren't magic. Put the right profile in the jaws, and you can "step" the crimp down the barrel as required.
When anyone tells me I can't do a workman-like job with tools I've done it with, it kinda leave me thinking they don't have much imagination. Stretch your mind a bit.
Soldering, correctly done, is probably the best method for electrical conductance, but solder isn't an acceptable mechanical joint. In many code jurisdictions, soldering is prohibited -- mostly because many people won't or can't do it well, but also because of the mechanical weakness of the joint.
They always taught us in electronics schools, "Make a secure mechanical-wrap before soldering; solder isn't glue."
Top piece would be inserted between the sides of the bottom piece and compressed with a vice. The lug would be placed into the opening of bottom piece. It will be compressed from top to bottom, while being restricted from the sides.
Looks like a nice evening welding project. I have all parts for it.
Yes I have seen them considering that I have a T&B crimper hanging in the shop. I don't see anything to them that couldn't be duplicated in a pair of cheap bolt cutters of the right size. I would want to know the size of the opening (easily done since they're hanging right there for me to measure) but other than that definitely doable for one or two sizes of wire.
If you're crimping welding cables, have a look at those crimping "jigs" that you hit with a hammer. They are under $20 and can be found on ebay and on the web. These were specifically designed for welding cables.