The Proteus Framebuilding Book - Proteus Bicycles

.8the frame will have cooled enough so as not to lose its annealedconditionThe final joint of the main frame assembly is the bottombracket. The problem with the joint is lining it up without anexpensive jig set up. To do this, you will need a decent pair ofbottom bracket cups, an accurate straight edge and a ruler. Screwthe cups into the bottom bracket shell. Only 2 or 3 turns arenecessary. Be careful not to cross thread them. If the cups won'tgo in even 2 or 3 turns you,may have to have the threads of thebottom bracket shell cut. One way or another get the cups in acouple of turns. Hold the frame in wood blocks by the down tube asshown in Fig .8.Fig.