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Old 20th Jun 2016, 8:05 am   #2
Radio Wrangler
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Join Date: Mar 2012
Location: Fife, Scotland, UK.
Posts: 17,157
Default Re: HP8640B questions

They will be imperial threads.

It may be that the original grub screws were not damaged... some of them were built with "Bristol Spline" type, not hex.

The U says your instrument was built at South Queensferry in week 36 of 1975 and it will have the inspector's stamp of an old (sadly late) friend all over the mechanical bits.

At a guess the threads may be 4-40, american style.

Can't afford the volcanic island yet, but the plans for my monorail and the goons' uniforms are done
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