Dispite working on those huge 4x8 optical tables at the day job, sometimes one must build rather then buy (actually quite often, this stuff isn't cheap) This university of Wisconsin internal document is Brilliant! really covers some cool flexure information ! Good basic coverage of 3 point kinematics and how to make one, although it doesnt cover the piano wire as a corner post kludge. Thank you Wisconsin taxpayers and NSF! Saved me a time then having to write a similar book,