Re: ATM Sources for tester plans

[Robert Duvall <rduvall@jlc.net>]

At 6:19 PM -0800 12/15/98, Ryan Hess wrote:
>Hi,
>
>It sounds interesting!  Can I ask who MSC is? If you can get me the web site
>or maybe a phone number, that'd be great.  Thanks!
>
MSC is a big catalog company that sells all kinds of mechanical type stuff-
micrometers, fans, screws, tubing, you name it. McMaster Supply Co. I think
is their full name. They don't sell Foucault plans or testers, just
micrometers for about $20, which is very reasonable. See
http://www.mcmaster.com/


But you do not NEED a micrometer. Just make a dial marked off in 100's or
do what I did - I made 180 marks in 2 degree increments and then I convert
degrees to inches: 2 degrees is 2/360 of a revolution, which is 1/20"
travel with a 20 thread per inch bolt, which is about .00027 inches.
Actually even every 5 degrees is good enough (72 divisions for .0007 inch
each- less than 1/1000 inch)
I used a Skippy(?) peanut butter jar top for the dial as it had grooves in
the outside edge- every degree, as it turns out!!! I used a permanent
marker pen to mark the grooves. I think I have a photo around, so I'll try
to update my site within a few days.

I have plans on my web site- can be made for a very few dollars. See my URL
below and look around for ATM and Foucault tester.



Robert Duvall
Force5 Telescope Making Resources

Software Engineer, Amateur Astronomer (TN),
and General Scientist (according to my son)
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