[Elecraft] Tightening screws

[Dauer, Edward]

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
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    Message: 25
    Date: Sun, 29 Oct 2017 08:34:04 -0500
    From: Clay Autery <KY5G at montac.com>
    To: elecraft at mailman.qth.net
    Subject: Re: [Elecraft] PA Transistors Maintenance in K2
    Message-ID: <d59c2bae-4588-cd72-3058-ff12e1a590f0 at montac.com>
    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.