> Jon Ellison wrote:
> >It's a technique that has been used by engineers for well over
> >a century, it works well in practice ..
> >try it, get two straight edges..
> >Set squares will do .
> >Place them back to back, hold then up to the light and look.
> >One thousandth of an inch is just discernible as a thin sliver
> >of light.
> >ten/ one thousandths looks like an open barn door.
> Lovely.... was that how it was done with the large polished
> granodiorite surfaces? Must be an amazing video with that
> sarcophagus juggling act that must therefor have been
> done....... you see because I have done it with a bread
> slice-sized slab of diamond sawed quartz and just a 6" metal
> ruler and I don't see any light 6" away unless it's
> >>>>>>perfectly<<<<<<< lined up. How was that lining up
> accomplished on the sarcophagus?
> Archae Solenhofen (email@example.com)
How did you line it up perfectly??.
Try it again .. Cheap and easy enough. all you need is two metal set squares and a light source.
Engineers have been using this method for well over a century. In fact at least back to the days of Whitworth.
So don't now try to say that it does not work because it opposes your argument.
Please do some research on the subject.
This is not a matter of opinion, it is a matter of known established and employed engineering fact.
Accuracy increases with experience. However you do need a machined accurate straight edge.
Here's the you tube video again..
Post Edited (07-Apr-15 20:03)