i wish i was that capable, i'd love to be able to do frame mods etc.
Have a go it's fun, I started by taking the rusted out back end of my Grandads bike and replacing that with one from an old falcon that came out of a skip, result a tribute to my granddad thats a turbo and occasional use bike. I use spirit levels, tape measures and bits of angle iron to jig things up. I silver solder rather than brass braze so I can use lower temps and a map torch for heat. What I really want to do is mitre up tubes and braze up something completely lugless.
while this isn't a type/model of brand i particularly like.