[time-nuts] He is a Time-Nut Troublemaker....

Neon John jgd at johngsbbq.com
Mon Dec 22 23:37:46 UTC 2008


On Tue, 23 Dec 2008 08:36:57 +1300, Bruce Griffiths
<bruce.griffiths at xtra.co.nz> wrote:

>Chuck
>
>It was a paper written around 1942 detailing the procedures used to
>align the sights of mass produced rifles for which it was impractical to
>have each rifle individually adjusted on a firing range.
>Unfortunately I dont think I have a copy of this any longer, however
>I'll keep an eye out for it.
>The alignment jig used a mirror attached to a cylindrical plug that was
>a close slip fit into the end of the bore.
>It wasn't perfect but far better than not adjusting the sights at all.

since we have so many shooting time nuts here, I thought that y'all would
enjoy this page:

http://www.neon-john.com/Misc/Antique_Chrono.htm

I bought this instrument new in the box at an estate sale.  The guy apparently
acquired it but never even cut the packing tape from the box.

It works perfectly, using the wire-break principle.  I made some screens by
gluing a few runs fine copper wire across the bull's eye to paper targets. The
display is transit time.  The velocity must be looked up on charts that
convert the time and the screen spacing into velocity.  I actually wrote a
little HP41 program to do that and dispense with the charts.

 Unlike my Oehler and its sky screens, it is not fooled by shock waves
(sub-sonic rounds) or debris (shotgun shells) and is very repeatable.  The
velocity results agree within reasonable statistics of my Oehler 33p.

One of these days when the round tuits become plentiful, I'm going to design a
little box to interface the Oehler skyscreens to this unit.

I also have one of Oehler's very first commercial chronos.  It's all analog
and uses the constant current/capacitor method of determining time-of-flight
and displays the results on an analog meter.  Again, it appears to use the
wire-break method (no manual).

John
--
John De Armond
See my website for my current email address
http://www.neon-john.com
http://www.johndearmond.com <-- best little blog on the net!
Tellico Plains, Occupied TN
Democracy is three wolves and one sheep voting on what to have for supper.




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