A local shop has volenteered to make new flexible staybolt caps and sleeves. I would like to know what type of steel is needed for these. Is there any documentation needed to show the FRA on the type of steel used?<p>Also, I know at one point the practice was to thread the sleeve into the boier shell, has this given way to straight sides slip in and welded? Lastly, are there standard sizes of caps and sleeves, or was the size a matter of who the manufacturer was?<p>Thanks in advance.<p>Roger<br>



Belpaire@aol.com

All materials used on a pressure vessel must have material certs and show traceablity. Robert Frandsen at the Grand Canyon Railway makes flexible bolts and is probably a good source for both information and the bolts. The old practice was to thread the sheet, screw the bolt through and bead it over like a rivet head. I believe that Robert Frandsen used the technique of just dropping the bolt through the hole and then welding. This is a better method as the bolt attachment is stronger and there are not any threads which are actually stress risers. Cracks usually start at a thread. flexible staybolts had standard size heads to fit an industry standard sleeve. Thread pitch is also specified if you in fact thread your bolts. Material I think is A26 however check that before you buy a mill run. Remember that your flexies need to be drilled 3/16 hole size through the length of the bolt.<br>