[time-nuts] WG mounting h/w (2)

J. Forster jfor at quik.com
Mon Sep 20 16:45:14 UTC 2010

I'm not so sure the alignment pins are "unobtanium". I think they are just
common Taper Pins:




> Another mystery solved!
> My (late) father-in-law spent most of his career at Varian-Eimac, mostly
> working on TWTs, BWOs, and the occasional magnetron. In one batch of his
> goodies, along with the H&S SMA torque wrench, was a little box with some
> tapered metal pins! I've wondered what those were for, and now I know!
> He was very happy when his daughter brought home someone who knew what
> vacuum tubes were, even if he did think that the RF work I did as a ham,
> even the 144 and 440 MHz stuff, was still practically DC...
> Bob K6RTM
> ------------------------------
> Message: 2
> Date: Mon, 20 Sep 2010 08:19:25 +0000
> From: Kit Scally <kScally at BYTECAN.com.au>
> Subject: [time-nuts] WG mounting h/w (2)
> To: "time-nuts at febo.com" <time-nuts at febo.com>
> Message-ID:
> <2AB674D4B0C99D4CA524E8530BA1B87C08DC5A19 at MSG02NSW.BYTECAN.com.au>
> Content-Type: text/plain; charset="us-ascii"
> Hi,
> Well, still not strictly, strictly true !
> In Ku & K band earth stations I've worked in, I've never seen shoulder
> screws used, although the equipment used was mainnly from the USA.
> Next to you precision adaptors, SMA torque wrenches etc in your personal
> goodie box are sets of tapered pins, about 35-40mm long - that fit various
> diameter WG mounting holes (the old metric vvs Imperial issue again).
> You insert a pair of pins on diagonal corners then add bog-standard SS
> hardware to the opposite diagonals & tighten. The tapered pins are then
> removed and replaced with another pair of screws/nuts. This ensures
> absolute (?) internal WG slot alignment. There are a few variations on
> this theme if you must have absolutely minimum RL within that section of
> guide or if one guide face is threaded. Hex-headed bolts are usually used.
> That may explain why shouldered bolts are seldom seen.
> Tapered WG pins fall into the 99.9999% unobtainium class of materials.
> Kit
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