[Elecraft] understanding screw sizes

[Pierfrancesco Caci]

Thanks for the explanation Don, I had it mostly figured out by doing an
inventory and reading that wikipedia page. 
If I may suggest, your words could be adapted to expand pages 7-8 of the
assembly manual and save us metric types some headscratching. 

Pf

>>>>> "Don" == Don Wilhelm <w3fpr at embarqmail.com> writes:


    Don>  Pf, Most of the screws in the K3 are #4, and the thread size
    Don> is in turns per inch (4-40).  These are standard sizes here in
    Don> the US - no metric size hardware is used in the K3 as far as I
    Don> know.  You have the reference link correct.

    Don> There is also some #2 hardware used in the K3 - it is the
    Don> smaller diameter, and has 56 threads per inch (2-56).

    Don> #6 hardware has a larger diameter and will have 32 threads per
    Don> inch (6-32)

    Don> The length of the screw threads will change depending on
    Don> whether the head is flat or not.  For flathead screws, measure
    Don> the entire length of the screw including the head.  For the
    Don> others, measure from the head to the end of the screw.

    Don> The washers are designated by the size of the hole.  Other
    Don> dimensions may exist if important, but often just the hole size
    Don> and the washer type (flat, internal tooth lockwasher, split
    Don> lockwasher) suffice for the description.

    Don> Sorry for those in "Metric Land" who do not understand the US
    Don> hardware system.  We tried to go metric many years ago and
    Don> failed.  Most of the auto industry is now metric, but for small
    Don> hardware, the US sizes predominate here.  We have to keep two
    Don> sets of wrenches if we are to have a complete set.

    Don> 73, Don W3FPR

    Don> On 4/9/2011 1:51 AM, Pierfrancesco Caci wrote:
    >> Hello, while lenght of the screws is given in the manual in mm
    >> also, I'm trying to figure out how to read the screw and washer
    >> diameters that are given as "4-40" and such. Is this the relevant
    >> standard?  http://en.wikipedia.org/wiki/Unified_Thread_Standard
    >> 
    >> For washers, the first number should be the size of the hole,
    >> right?
    >> 
    >> Pf
    >> 
    >> 
    >> 

-- 
Pierfrancesco Caci, ik5pvx