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

k6rtm at comcast.net k6rtm at comcast.net
Mon Sep 20 14:58:41 UTC 2010


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> 
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<2AB674D4B0C99D4CA524E8530BA1B87C08DC5A19 at MSG02NSW.BYTECAN.com.au> 
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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 
VK2LL 




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