You don't need silver solder, the stuff in the plumbing dept. at the hardware store will work. Just make sure that you use a paste flux and that all the parts, including the iron, are CLEAN! CLEAN is the key when soldering.:wink: I use 220 grit silicon carbide paper to sand the oxidation off the brass tube and around the hole in the casing.
By the way, my article in the library shows me soldering on the INSIDE of the tube...I don't recommend that anymore. After you drill the hole for the tube, chamfer(countersink) it a little. Then cut your tube about 1/4" long and solder around the OUTSIDE, the chamfer will provide a little "valley" for the solder to sit in. You can trim the tube after you solder it.
Then drill out the tube with a SHORT 1/4" drill bit about 3/8" deep, no more than that. That will allow the transmission to slide past the headcase. You CAN omit this step but it makes the transmission hard to install.