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This is the method used by the Germans.  They wrapped the scale around aluminium tubes.

-----Original Message-----
From: NavList@fer3.com [mailto:NavList@fer3.com] On Behalf Of Gary LaPook
Sent: Friday, July 03, 2009 4:02 PM
To: NavList@fer3.com
Subject: [NavList 8928] Re: Manufacture new Bygraves?


I have had great success with printing the scales of the flat Bygrave
and wrapping them around a tube and sealing them in place with clear
adhesive plastic sheets.

Here are some pictures of one example:

http://www.fer3.com/arc/m2.aspx?i=106329&y=200809

Links to the scales:

http://www.fer3.com/arc/img/107473.lapook2.pdf

http://www.fer3.com/arc/img/107473.lapook1.pdf

http://www.fer3.com/arc/img/108719.revised%20form%206-18-09.pdf

http://www.fer3.com/arc/img/107419.bygrave-manual.pdf

I picture of one made by Geoffrey Kolb:

http://www.pisces-press.com/graphics/Bygrave.jpg



Try it.

gl



Hanno Ix wrote:
> Hello:
>
> I agree. Bygraves could be build.
>
> However, there are some cumbersome questions, the most obvious being,
> How to generate a drum-shaped scales with the required accuracy and
> resolution. Remember, we will have to maintain sub-millimeter acc/res
> over many turns, with "many" meaning perhaps 20 to 50. This should be
> possible, but is still not easy.
>
> If someone could generate the mechanical construction and quality
> assurance methods for this challenge we could talk about manufacturing
> more seriously. Her are my ideas:
>
> Personally, I am thinking of an ink-jet head printing on a turning
> drum where the printing is synchronised with a digital encoder on the
> drum' s axis. The process control could be handled by one of the
> relatively simple contollers on the market.
>
> Another approach would be to replace the ink-jet printing with an
> engraving system.
> With the first  I personally have experience, with the second none
> whatsoever.
>
> However, more problems lurk. What are the limits for excentricity of
> the drums when in use? How about friction? How to stabilize the thing
> when under the influence of temparature changes, humidity, sun's UV,
> spray salt water, etc, etc.
>
> So, you can see that the conceptual simplicity of the Byraves is
> offset by many practical obstacles.
>
> Compare this, for instance, with the Ageton method (H.O. 211)! Only 12
> pages of a table, a sheet of paper and a pencil is virtually all you
> need to get a generally higher res/acc than with a practical Bygrave.
>
> Yes, you will also need the skill and concentration to exercise the HO
> 211 calculations under virtually any condition at sea - particularly
> when you are a submarine commander at war. Well, I guess, in this case
> a Bygrave, well designed under a government contract, does make sense!
>
>
>
>
>
>
> --- On *Fri, 7/3/09, Greg Rudzinski //* wrote:
>
>
>     From: Greg Rudzinski 
>     Subject: [NavList 8924] Re: Manufacture new Bygraves?
>     To: "NavList" 
>     Date: Friday, July 3, 2009, 9:40 AM
>
>
>     There must be a combination of PVC tubing that fits on itself snugly.
>     If the white PVC were engraved with black and red scale markings as a
>     regular plastic slide rule is then I think you would have something.
>
>     On Jul 3, 12:18 am,      > wrote:
>     > A few years ago, when I and a couple of friends wanted each to
>     own a gear hobbing machine, we cooperated. One made the casting
>     patterns and saw them through the local foundry, another did the
>     heavy machining and I did the small parts like feedscrews and
>     their nuts. It occurs to me that several handy people could
>     combine their skills to produce replica Bygraves slide rules.
>     There will surely be someone who knows where to access tubing in
>     which each size nests snuggly in the next largest size, someone
>     else will know how to produce hard-wearing replica scales, another
>     may be prepared to turn the bobbins at each end and I would
>     volunteer to do small bits of metalwork. The results do not have
>     to make profits, though a little would be nice. Since there seem
>     to be very few surviving Bygraves calculators, one could at least
>     have the satisfaction of owning a replica. The starting point of
>     course would have to be accurate, dimensioned drawings of an
>     original, preferably following the metric system, so the
>     manufacturing consortium would not have to be confined to the USA.
>     >
>     > Any offers/takers?
>
>
>
> >




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