A roto rule, named a Rotomatic, has a 6.5 inch measuring unit with extension bars of 6, 12 and 18 inches. The measuring unit is a 3/8 inch threaded rod , threaded 16 threads to the inch. This rod is marked at each half inch and has a nut like object that spins on the rod. The nub like object is marked on one side for reference. There is also a locking nut to lock the nut like object in place if desired. One can measure to an accuracy of 1/64 of an inch.
earlier, Tom Hodges, wrote: >Hi, Tom: > >I must have come in on the back-end of this email; what specifically are you >referring to? Also, what is a roto rule? > >If I want to find the angle of something, I just my Sears 10" electronic >level and tells you the exact angle. > >Thanks, >Tom > >On Wed, Jun 18, 2008 at 7:31 PM, Tom Fowle ><<mailto:fowle%40ski.org>[EMAIL PROTECTED]> wrote: > > > wonder why you couldn't have a device with two blades on a pivot with a > > way > > to fasten the roto rule across the blades to make up a triangle. > > Then "simple" trigonometry could let you adjust the ruler to get a desired > > angle. This would be where you may have calculated the angle you want but > > not have a reference from which to get it. > > > > And, obviously you could measure an existing angle with it too if you > > actually needed the measurement. > > > > Yeah, you can find relatively accessible protractors, but something like > > this > > might be pretty easy to fabricate if we get it > > figgered out correctly, and might be very accurate? > > > > So Dan Rossi, help with the gtrig. > > > > Let's assume most work would need angles less than 90 degrees as you can > > always subtract from 180 and measure the opposite angle. > > > > There must be something wrong with this? > > > > Thinking caps on plese. We could build a prototype > > and document it here at Smith-Kettlewell if nobody beats us to it. > > > > tom > > > > > > > >[Non-text portions of this message have been removed] > > >No virus found in this incoming message. >Checked by AVG. >Version: 8.0.100 / Virus Database: 270.4.0/1509 - Release Date: >6/19/2008 8:00 AM John [Non-text portions of this message have been removed]
