[GreenKeys] Re: Hold down screws for the M28 or M35 typing unit

Mon, 24 Jun 2002 16:24:14 -0700

Thanks Ben,  You are absolutely correct.
Don

>Comment:  Teletype tended to use National Fine series threads. 
>These have more threads per inch than you would expect in a screw 
>from the hardware store.  For example, we all have tons of  National 
>Coarse (NC) #6-32 screws around.   But Teletype used a #6-40 NF 
>series.  If the mounting screws are 1/4-32, that also is NF.  The 
>usual screw at the hardware store is, I belive a 1/4-20 thread.  I 
>never heard why they used NF screws; I suspect it may have been to 
>keep the screws from loosening under the constant vibration.
>
>So be careful to start any unknown screw gently with your fingers, 
>and if it binds up, you may have a NC screw trying to go into a NF 
>tapped hole.=
>
>Ben Stephens K9KOM=
>

-- 
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Don Robert House
URL: http://www.nadcomm.org
email: [email protected]
email: [email protected]
email: [email protected]
email: [email protected]
email: [email protected]