Tom,
I did not mean to ever imply that I am new to rigging. I have been working as a yacht rigger for 7 years now, and have been involved with yacht rigging, sailing, cruising and boatbuilding my whole life. I am however aware that there are many who have been rigging much longer that me and I just always try to make it clear that "I" do not yet know everything, hence am
always learning.
I prefer to stay away from rivits as a rule becasue I so often find them not doing the job they were intended to correctly, I even had a step pull out from under my foot the other day (more like two months ago actually) because somebody somehow didn't rivit it on correctly. I see it all the time, more often that lousy machine screw fastenings. This is perhaps a result of rivits being very popular in fierecly price competitive production enviroments, where quality control can be more difficult. oh, and they are a mess to remove and re install, drilling and tapping only makes a mess once, if you protect the threads with lanacote of tef gel or lifeseal when installing them.
You are quite right that the wall thickness should be considered, as one wants to get as many threads engaged as possible, so why would you use a self tapping screw. I was under the impression that these were the weakest fastner commonly used in rigging. I did take your advice and just ordered a couple of 'Design Assistance Corporations' Instruction/Training Manuals , specifically p/n 540-MAN Industrial Fastner Manual
http://www.dac-3d.com/DACTRNG/PRODBOOK/540BOOK.HTM and for curiosity and further information p/n 550-MAN Crane and Rigging Manual
http://www.dac-3d.com/DACTRNG/PRODBOOK/550BOOK.HTM
I however for now will continue to avoid rivits if at all possible, and rather use the correct thead count and diameter for the job.
"13/64 bit and a #10 screw...why even tap!? " ...wouldn't that screw just slide through the hole ? I suppose that was your point, but I just didn't want anybody drilling a 13/64 hole expecting a #10 fastner to work in it.... : )
Constructivly Participating,
Brian