DECtape reel gauge

Paul Koning paulkoning at
Fri Aug 5 10:07:24 CDT 2016

> On Aug 5, 2016, at 10:43 AM, tony duell <ard at> wrote:
>> Interesting.  When looking at this I tripped over another DEC related item:
>> I'm not sure what you'd use it for unless you were manufacturing DECtape
>> reels, but it certainly is interesting.  You could make one yourself, if you
>> have a lathe and the ability to hold tight tolerances.  One of the photos 
>> actually shows the dimensions as written on the gauge.
> Which suggests the spec is 2.5" +/- 5 thou (or thereabouts).

Yes, that's what those numbers imply.  It sounds plausible, given the springy hub used on DECtape.

I remember once or twice having to use a piece of punch card as a shim to keep a reel from coming off.  Not clear if wear was involved or an out of spec part that slipped through.


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