Scott,a while ago you asked me for some info regarding a "batt rivet".I have some more for you regarding the punching of holes.It is not a well known fact that all holes were punched to a formula in H&W's plater's sheds.In today's fab shops people are merrily punching away not knowing why punches keep breaking.They believe that they are not putting enough oil on the punch,to help it penetrate the steel.In all my time at H&W did I see one punch break or oil used.If you were to buy,say a 22mm dia punch off the shelf,you would get a 23.2mm dia die (thimble).This is ok for plt up to 6mm thick.In the case of a shipyard however,punching holes in thick plt the punch would only last about a dozen holes.The punch always breaks on the way up.In other words it gets pulled off.To punch 22mm dia holes in 20mm plt,you take the dia of the punch & add on 1/5th the plt thickness.This gives us 22+4=26 for the dia of the die.Most of the time the holes would be marked on the fay side,that is the faces of the plts that come together.The side of plt where the point protrudes from is countersunk.This forms a type of wedge,which is very strong in tension.Alas,Titanics shell rivets were subjected to shear,the rest is history.
I posted a thread on this a while ago,comparing butt laps(british)to butt straps(european).Cap'n David G Brown agreed with me regarding the shear aspect created in the laps.I know the straps increase the weight dramatically but at least the shear factor is shared between all the plts in the strake concerned.I've often wondered if the board of trade had known how the water got in,would they have made butt straps mandatory.I am interested to hear your point of view.
seven degrees west.
regards.
dw.