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BrianClement / Demo3

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pith spike - Part 01 #278

Open BrianClement opened 7 years ago

BrianClement commented 7 years ago

DB0087 [Created: 2017-01-20 by Jonathan]

When half-disc samples are mounted in the sample cassette the pith is expected to be centred on a specific spike with reasonable precision (+/-1mm?). This is to make transformingbetween cassetteand sample coordinates a little easier.

For this to work:

(a) the two sample cassettes need to have the pith spike in the same location (in both directions) relative to the mountingtabs (b) the pith spike needs to be clearly identifiable (c) the operator needs to know this is how things are done

Currently (a) is not true. (b) and (c) may or may not be true.

BrianClement commented 7 years ago

[Jonathan - 25/01/2017 5:31:12 p.m.] JL initially estimated a difference of ~5mm in pith spike position between cassettes. After careful measurement, he has revised this to ~1mm. Since this is close to his estimate of how precisely the sample can be positioned it does not seem worth the effort to fix.

In the future cassettes will be manufactured more precisely. To this end, and for documentation purposes, engineering drawings of the cassette design are required...