Incorrect RE the inch
In 1959, the definition of the inch was changed to be EXACTLY 2.54cm, a
change of about 2 millionths of an inch
The screw machine issue is real (and the 127 tooth transition gear is a dog)
That said, a LOT of machines use threading dies, which have the pitch ground
in
-----Original Message-----
From: TowerTalk <towertalk-bounces@contesting.com> On Behalf Of Richard
Karlquist
Sent: Wednesday, June 19, 2024 3:51 PM
To: Steve Walter <stevewalter90@gmail.com>
Cc: towertalk@contesting.com
Subject: Re: [TowerTalk] Junk Connectors (was Re: How lossy are PL-259s at
HF?)
I have had a pet theory about off shore threads, may or may not be
valid:
If a manufacturer in Asia has screw machines calibrated in metric threads,
there is a double dilemma: metric threads are given in mm per thread
while imperial threads are given in threads per inch. Thus there is a
reciprocal relationship in addition to the factor of 2.54. Along with this,
there is the problem that any errors accumulate and get worse with more
turns of engagement. Also, the factor of 2.54 mm/inch is only an
approximation. The official conversion is that there are exactly 39.37
inches in a meter. This translates to 2.540005 mm/inch. I don't know
if that is part of the problem.
I could quite possibly imagine a case where Chinese SO-239 threads fit
Chinese PL-259 threads perfectly if they were made on the same screw
machine, but would not mate with Amphenol parts.
---
Rick Karlquist
N6RK
On 2024-06-19 09:35, Steve Walter wrote:
> I bought a bunch of Amphenol 83-1SP connectors from Davis RF for my
> tower project. No problems until I tried to mate them to an Array
> Solutions StackMatch; they could not get started...talk about
> frustrating! They worked fine on everything else I have here. Other
> PL-259s worked on the StackMatch. I ended up replacing the SO239s on
> the SM with Amphenol and the problem was solved. Joel at RF
> Connection who supplied Array Solutions the SO239s blamed the 83-1SPs.
> I was skeptical.....maybe not so much now that I hear Rons report.
>
> Steve WA3A
> _______________________________________________
>
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