QUOTE (Canniboomer @ Jan 13 2008, 08:02 PM) <{POST_SNAPBACK}>
I would also warn that the market is too-crazy about Ti fasteners by now, and most customers will just ASSUME they are stronger. Indeed, the Titanium is stonger "pound for pound" compared to most steels, but in a "bolt for bolt" comparison, they are usually much weaker. For any applications where high strength is an issue, the required grade of Titanium is still hard to find, and at even-more insane (aerospace) prices. Most Ti bolts to the motorsports industry by now are the equivalent of a grade 2 for strength. Even Ti bolts that are equivalent grade 5(metric 8.8) are less common, and still not suitable to replace the Cannondale or Japanese suspension bolts. It just pays to beware, and know what you are buying.
Agreed, and an open crystal stucture cannot be seen by analysis, so even if you get the material analysed you can't tell how strong it's going to be.
You could test a bolt for strength but you do get a lot of 'scatter in strength', like you do with ceramics, with variable crystal structure.
Buy specced material only from a recognised and certified source (ebay doesn't count...)
Fortunately I have a friend who used to work for Rolls-Royce aero engines and he does consultancy work now. He knows what's best to use, where to buy it and how best to work with it.
Even good Ti isn't as strong ultimately, as good steel, especially not in shear.
I had thought about starting with a drilled piece which is too thick and heating it to 900c so the Ti goes superplastic and then rolling it in the areas where the pivot is in shear. The OD would need turning down as normal to bring it to size. That way the pin will be hollow for light weight but thicker walled in the crytical areas for greater shear strength.