NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Paul Dolkas
Date: 2016 Oct 20, 10:11 -0700
Bob-
After looking at the printout of the slide rule, I have to say that converting it to a 3-D model is quite possible, but a hell of a lot of work. There’s hundreds of marks that would have to be accurately measured and manually entered into the model, one by one. Even if you have a dxf file, where the marks are already in a 2-D cad format, translating them into a 3-D format would keep me busy for a long time.
The best way, I think, is to give the file to a engraver that can work directly from the file, if that’s possible. I was impressed with the custom ruler somebody posted – it’s super precise, and the PCB material it’s printed on is pretty robust stuff.
Having said that, using 3-D printing to make the sliding parts themselves (that the scales could be glued onto) would be a trivial thing.
Paul Dolkas
From: NavList@fer3.com [mailto:NavList@fer3.com] On Behalf Of Tony Oz
Sent: Thursday, October 20, 2016 7:29 AM
To: paul@dolkas.net
Subject: [NavList] Re: Traditional navigation by slide rule
Dear Bob,
Are you sure the 3D-printing is really necessary?
I think a much simpler and cheaper way exists.
Consider a backplane to which a pair of spacers are glued, a movable spacer for the slider's scale and the three scales glued to the relevant spacers. The key idea is to arrange the stator's scales to be wider than the movable spacer so that they (the static scales) overhang that spacer preventing its' falling out.
The (rather simplistic) sketch is attached.
All this make it possible to rely on laser engravement of the scales - I'm sure a much more precise process. The wide enought gap between the spacers - provided that the scales themselves are tightly pressed together by their edges - make glueing everything easier, just make sure the scales' indexes are aligned properly. One does not need to worry about the parallelism of the spacers, etc.
Two-layer white-cover/black-substrate plastics exist of wide list of vendors.
So an inexpensive DIY kit of the three scales and a backplane (with usage instructions engaved) is quite possible.
Regards,
Tony
Attached File:
