I can see the point of this for mass or machine-made production, but for a
home-built kit there’s a simpler idea. If the instruction is not to
overtighten – as for the screws holding plastic bezels in place – I use a
screwdriver with a smaller diameter handle. If the screw needs to be
ferociously fastened, then a larger diameter handle. The relative mechanical
advantage could be calculated but probably not the actual torque – that’s a
function of muscle exertion and I don’t know how to calibrate that. When the
instruction says “Do Not Overtighten” I just reach for a smaller tool.
Ted, KN1CBR
------------------------------
Message: 25
Date: Sun, 29 Oct 2017 08:34:04 -0500
From: Clay Autery <[email protected]>
To: [email protected]
Subject: Re: [Elecraft] PA Transistors Maintenance in K2
Message-ID: <[email protected]>
Content-Type: text/plain; charset=utf-8; format=flowed
It is possible that an explicit torque has never been calculated.? It is
not a particularly hard thing to do however.
I do not have a K2, so I can't do it, but here's the idea:
1) Fastener size/type, material, thread spec: (e.g. 4-40 x ___ pan head,
phillips, zinc coated, non-rated steel
2) What does fastener anchor in?? (e.g. aluminum heat sink, what alloy
aluminum, thickness of threaded area.
3) Thread spec... not JUST the #4, 40 tpi, but the rating for thread
engagement.
4) Check the specs for the RF transistor.... package, et al.? Docs
may/should have a max torque spec for the package.... maybe... package
material, etc.
5) # of fasteners... usually 1 maybe 2.
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