How about claims that certain oil additives can reduce internal friction and let the engine run cooler, seems to work on my Harley - but difficult to proove.
When I was a Kid I had a meccano set as well as other building ang science kits. No computer games in those days. There must be an opportunity to reinvent these toys for our kids to play with. Engineers are born. they needs toys to develop their skills.
Ajuk is right. I worked in the timber construction industry in the early 70's when metrication was introduced. 1/2" ply became 12.5mm and 3x2's 75 x 50's. It was very easy!
A pound at the design stage equals a thousand at the rectification stage (in construction).
Whilst I agree that the ultimate shear will be o.62 of UTS it must be remembered that the shear capacity will be less than that. The bolt will be permenantly deform befor it breaks completely. The shear capacity can be taken as 60% of the Yield stress x 90% of the cross sectional area.
Have you looked at expanding bolts? (known as hollow bolts in U.K.)
Another system is Flowdrill where a tool is rotated at high speed ad pushed through the steel, forming a swaged cone of material on the internal face. This can then be tapped and bolted in the usual way. Tool cost is approx...
