[R-390] Cosmos Linearity Adjustment Tool Sizes?

[Roy Morgan]

At 01:54 PM 10/31/2006, Tom Norris wrote:
>I realize this has been asked a dozen times before, but I've searched
>the faq and the archive and can't find it --
>
>What size of tool do I need to perform the linearity adjustment on a
>Cosmos PTO?
>
>Looks like a 4 flute, size "teenietiny"

My CosmosPTOnotes.txt file has info for you:


CosmosPTOnotes.txt
 From K1LKY

Date: Sat, 13 May 2006 03:57:41 -0700 (PDT)
From: "KC8OPP Roger S." <kc8opp at yahoo.com>
Subject: Re: [R-390] Cosmos Linearity tool
To: jonklinkhamer at comcast.net

Jon,

This is what I use, fits great.

Snap-On multi spline L-Shaped wrench #MS2A.

This is a four flute spline wrench that measures .033
inches across.

I cut it down and clamped it in pin drill handle so I
could reach in and adj the screws.

Good Luck.

73's
Roger
KC8OPP


--- Jon <jonklinkhamer at comcast.net> wrote:

 > Hello Group,
 >
 > Can anyone recommend the tool for correcting the
 > linearity of a COSMOS PTO.
 > I have the PTO   that does not have the tiny screws.
 > They look like a spline
 > socket, I have the smallest available one (I think)
 > at 0.032 OD and it does
 > not fix. Is they a commercial tool out there?
 >
 > Thanks,
 > Jon, KB1DC
 >

Date: Sat, 13 May 2006 13:17:52 -0400
To: r-390 at mailman.qth.net, jonklinkhamer at comcast.net
Subject: Re: [R-390] Cosmos Linearity tool
From: shoppa_r390a at trailing-edge.com (Tim Shoppa)


"Jon" <jonklinkhamer at comcast.net> wrote:
 > Can anyone recommend the tool for correcting the linearity of a COSMOS PTO.
 > I have the PTO   that does not have the tiny screws. They look like a spline
 > socket, I have the smallest available one (I think) at 0.032 OD and it does
 > not fix. Is they a commercial tool out there?

Is it possible that you ended up with a six-fluted 0.032" spline key?

I bought a "four-flute spline L-key, 0.033" Dia" from McMaster-Carr
(part #7048A11). It was not in stock at the local warehouse and they
had to ship it in from Chicago. It fits but it still isn't easy
work (especially when you've got to repeat dozens and dozens of
times.)

Like Roger I find it easiest to use if I cut off the "L" and put it
in a pin vise. Even then it takes a LOT of skill and patience
to stick it through the radio chassis, through the PTO bracket,
through the PTO can, and into the screw. It was just about impossible
when I was using it as a L-wrench (and I have some experience working
tiny SMT stuff and watches and clocks. Easy to blame on my "fat fingers"
but the same fat fingers let me solder 0201 SMT stuff...). What would
really make a world of difference, if I had one, was a pin vise that
had a little spotlight on the end of it.

The hole in the screw is so tiny that a lot of times it is hard
to get the spline in especially if dust or oil (or worst both!)
are inhabiting the spline socket. When I was degreasing/degunking
my PTO I took out all the spline screws and ran them through my
ultrasonic degreaser.

Tim.


- Roy Morgan, K1LKY since 1959 - Keep 'em Glowing
13033 Downey Mill Road, Lovettsville, VA 20180
Phone 540-822-5911   Cell 301-928-7794
Work: Voice: 301-975-3254,  Fax: 301-975-6097
roy.morgan at nist.gov --