[Amps] Countersinks - was Alpha 76A

Paul Christensen w9ac at arrl.net
Wed Nov 26 07:55:44 EST 2014


Rick, Carl and all ‹ many thanks for answering my questions.  I¹ve settled
on 82 degrees and now have the panel complete.  All measurements need to
be cross-checked again.   In doing this on a bare, stripped panel, I¹ve
been trying to take measurements that don't result in cumulative errors.
A caliper and micrometer are used on openings, while distances are set
with a precision machinists ruler.   This worked well on my Alpha 77 amp
project.  With that amp, the only panel error occurred when I did not drop
the TUNE and LOAD legends low enough to accommodate the larger version of
the Raytheon spinner knobs - that I now prefer.

To me, the new 76 panel looks very close to the original (at least in the
software editor) but for trademark protection issues, the ETO logo is not
used.  However, in place of the logo, the CAD program allows you to
engrave or silk-screen one¹s own callsign.  If this turns out as planned,
a 78 panel may be next although the band switch has a unique and complex
legend due to the broadband ³no-tune² option.  That legend may have to be
designed in a package like Corel Draw, then exported as a CAD file.  A
77Dx/Sx panel design is also complete.   The panels can be anodized and
engraved using many common colors ‹ or powder coated and silk-screened.
Here¹s a link to the 76 panel image.

http://72.52.250.47/images/76.jpg

Paul, W9AC

-----Original Message-----
From: Rick <nm3g at triad.rr.com>
Date: Tuesday, November 25, 2014 at 6:37 PM
To: Paul Christensen <w9ac at arrl.net>, "amps at contesting.com"
<amps at contesting.com>
Subject: Countersinks - was Alpha 76A

Good evening Paul,

82° is the ANSI screw standard (commercial).
100° is the MIL/Aviation standard, to accommodate rivets and fasteners
in thin sheet metal (more of a bearing surface to keep the head from
pulling through).
90° is metric.

I'd go with the 82°.

Hope this helps.

73,
Rick
NM3G





More information about the Amps mailing list