While installing flexible staybolts the 1938 Flannery catalog states "All bolts should be released slightly from close contact with the sleeve before riveting.".

Does anyone have any written reference as to what dimension "slightly" is? Thanks...............mld

One old boilermaker told me to back them off 1/8 of a turn after screwing them in tightly. Interesting to see how this information compares with other sources.

"Tightly"?; I was told by someone we all know, " turn them until it touches; back off an 1/8 of a turn; turning them in tightly will, after several bolts, will have a tendency to bow the inner sheet .

Maybe one at a time? I suppose like the PRR, the Southern had their own ways...... at least the 1/8 of a turn is the same. I wonder what you do with the welded in rather than threaded in bolts?

Dave, not sure about the welded ones; I would assume that if you let them "bottom out" against the sleeve, the weld "Bead" will cause it to pull as it it cooled thus again bowing the sheets as you go.

Maybe some sort of mechanical spacer that could be removed or would melt out? somebody must have some information, they were later technology.

That's what popped into my head: some sort of spacer. I wonder if on the shop floors, this was taken into consideration.

Regarding welded flexi bolts. I have seen one style of bolt where the spherical bearing surface is a nut that is threaded onto the bolt. There are notches in the top of the nut at the outer edge where a special socket is used to turn the nut. Could this be the answer for what is done with welded flexis?

Ed