NavList:

Hi Hanno Ix

I don’t think we will ever be done with this discussion.  The Bygrave and its direct descendants will remain a fascination for some, like me!

Others are bored to tears.   For heaven’s sake, it is just a pair of cosine, cotangent scales.  {Or secant, tangent scales, depending on your persuasion. }

The conversation on a consortium re-manufacture of a Bygrave like slide rule has foundered on exactly what to manufacture.  Some, like me, would like a reproduction of the MHR-1, which is IMHO, the class act of them all.  Others would like to produce much cheaper models, using common materials. 

I would love to extend the scales to angles less that 20’ and above 89deg40’ on the scales.  This would require far longer scales, something that the MHR-2 attempts but does not succeed at.  I have provided some study to how long the scale would have to be.

Secondly, I would like to explore Bygrave’s patent statement that a second set of scales can be used around 0 and 90 degrees.  I have an idea in mind how to do that, but it is not yet formalized for realization.

Perhaps there is some area you wish to explore?

Best Regards

Brad