[Taxon]: Measure.Length.SingleEnded

[ryanmwhitephd]

Contact Details

No response

What is the process type?

Measure

Measurand

Single ended (change name) length measurands correspond to two devices:

• Gauge blocks
• Step gauges

Measurands for gauge blocks correspond to a reference plane and a point (center) on the end of the gauge block, normally to include a wringing length. Single ended measurands for step gauges, however, are point to point.

Parameters (Gauge blocks, likely)

• Length (required for uncertainty and capability search--measurement range)
• Material (thermal expansion and contact deformation may affect measurement uncertainty)

Parameters (Gauge blocks, maybe but more likely relevant only to instrument spec documents)

• Grade (different grades would correspond to different measurement systems / techniques and hence the uncertainty) but taxons do not capture the measurement technique, only the measurand. For any one taxon, a lab may offer a choice of CMCs that correspond to different techniques with different uncertainties.
• Cross section (defines the measurement axis and/or the reference point position on the gauge end). This becomes a parameter if a lab might have a capability for some cross sections and not others.
• SupportCondition (a parameter if applicable to long gauge blocks)

Parameters (Step-gauge parameters, likely)

• Length (required for uncertainty and capability search--measurement range)
• Material (thermal expansion and contact deformation may affect measurement uncertainty)
• SupportCondition (may affect error and uncertainty due to deformation in one position relative to another)
• Unidirectional; bidirectional

Parameters (Step-gauge parameters, maybe but more likely relevant only to instrument spec documents)

• Step spacing (step length)--no, distances specified in the instrument spec (calibration request)
• Number of steps--no, as with step spacing
• Axis (as above, unless it impacts capability or uncertainty)

Other details Support condition (depending on total length of block, support condition can affect the length error. Weight of the block can have a significant impact, for instance). The support condition may be relevant as well depending on the use of gauge by the client. Axis

Kind of quantity

Length

Does the measurand require a special token?

None

Qualifiers

SingleEnded suggested as a qualifying term to distinguish the measurand of length the relies on one face of the gauge block. Other technique which rely on two faces of the block are also possible, for example, with the use of a double ended interferometer. This qualifying term may be describing the technique more than the measurand. Another option: Differentiate taxons as Wrung (gauge blocks as end standards when the measurand includes the wringing layer), EndStandard (end-to-end without wringing layers--includes cylinders et al. and perhaps gauge blocks without the wringing layer), or LineStandard (line to line on a scale).

Taxon Name

Measure.Length.SingleEnded? This may break up differently as mentioned above after expert review.

Additional information

[NIST Gauge block handbook] (https://www.nist.gov/system/files/documents/calibrations/mono180.pdf) [Gauge block calibration by optical interferometry at the National Research Council Canada] (https://nrc-publications.canada.ca/eng/view/object/?id=521ea7a1-02c2-4dd7-a4f9-f1290cf53cdc) {DimVim] https://www.bipm.org/en/committees/cc/ccl/dimvim

[MarkKuster]

Revised to indicate likely and unlikely parameters and the reasons therefor. Also suggested the option to discard SingleEnded as a qualifier and differentiate measurands by length definitions.

[ryanmwhitephd]

'EndStandard' aligns with the KCDB, and 'Wrung' allows to differentiate between the measurands rather than technique. The same technique (optical interferometry) could be used to measure the length including the wringing layer or without, likely changing the uncertainty as well.

NRC service descriptions includes information on the support conditition: "Gauge blocks up to 100 mm are calibrated in a vertical orientation, wrung to an optical flat. Length bars over 100 mm and up to 1000 mm are calibrated one at a time in a horizontal orientation, supported at their airy points and with a small optical flat wrung to one end."

I'm assuming that NRC can measure the length including the wringing layer or without despite the technique relying on an optical flat.