I use aluminum square rod for the top & bottom ribs to hold in place. You can get a way with steel but the chance of soldering it into place is also there if you get carried away with fluxing.
Instead of the wire method,,I use small C clamps to hold things together. The square rod makes for easier clampng than round stock and holds the ribs just as well.
I never had good luck with the twisted wire method & tapered nails. It works great, most use the method. Just not for me.
Over heated wire twists stretching out of shape when the tapered nail is supposed to tighten the assembly, ect. I know,,don't over heat them, but it's bound to happen. They sit in the open like a stove coil.
Make sure the bbl spacers are in place before replacing the ribs. They will allow evn side clamping of the tubes.
Keep track of where the spacers are in side so you can place the side clamps at those locations.
Don't over do the pressure on these or any of them for that matter.
Also clamp the forend hook in place so that doesn't move on you.
I tin the ribs with a simple electric soldering gun. Easy, clean and quick. Flux the rib surfaces first,,load up the point on the gun and you can tin quite a few inches of rib in one quick slide before reloading the tip w/solder.
I even found you can do most of the bbl surfaces with one. From around the forend hook back, they get a bit too heavy to tin with the pistol grip WEN soldering gun. But the rest is done quickly and evenly.
I use lead/tin solder. The greenie tin/silver soft solder is stronger but it doesn't tin the surfaces as easy IMO. Plus it stays bright white unlike lead solder that oxidizes to dark grey.
Any solder line stays forever like a white hairline thread along the bbl lenght with it.
For flux I use regular No-Corrode paste. Nothing fancy. Acid flux is great and I use it occasionally for some jobs. But the extra cleanup isn't necessary with the paste,,,and I've seen the nasty aftermath of acid flux if the clean-up isn't done well.
Level the bbls with a simple set of parallels as stated above. Level the bbls from below,,then also level the rib on top. Both may need adjusting. An eyeball last look isn't a bad idea.
I use a couple old parallel files for the job.
Start the soldering job from the breech. That's where the most heat will be needed. I use a propane (bottled) torch. It does take a while to get it up to heat but it will do the job. The last thing you want is to over heat it. Work towards the muzzle.
Also if you start from the muzzle, the rib will expand from the heat and by the time you reach the breech end there may be a bow in it w/o enough room for it to lay down flat and tuck nicely into the short rib. It's all soldered down behind you now so you're stuck taking it off again. Same with the bottom rib up against the forend hook.
I place the bbls horizontal on one wooden peg in the bench vise. They fit fairly tight on that peg but I can still rotate them to work at any angle/top/bottom as I need to. I turn them by grabbing onto the bbl lug w/a padded pliers made for that.
Some heavy sets I place another plug in the muzzle of the same tube and it's supported by a simple T-rest standing on the floor. Makes for a solid work stand.
Lots of different ways to do the job. You'll find what works best and easiest for you as you go along.
Take your time while you work. Solder doesn't go bad while working with it as long as you don't over heat it. Everything should be clean to start with of course.
