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Hi there,
I have just moved to a lab where they have recently had their calipers callibrated. Now they have sourced a rectangular piece of stainless steel (home made gage block), drawn on lines in permanent marker so that there are 3 locations of differing measurement that are always made in the same place, then carried out repeated measurements on this home made gage block with their recently calibrated calipers. This has given them consistant readings, and are now proposing to use this supposedly calibrated gage block to calibrate the same calipers in the future.
The calipers have been calibrated and have shown a measurement of uncertainty of +/- 0.0161mm. The item that we want to measure with the calipers are sieves, with the smallest diameter to measure is 4mm, and according to the procedure needs to be measured within an accuracy of 5%, which is 0.20mm. Now usually I go by the theory that anything that calibrates an item needs to have a count of at least 1/10th of the item being calibrated. However in this case, we dont need the calipers to be that accurate as they only need to be accurate to 0.20mm.
Can someone please confirm whether this method is acceptable in ISO 17205, or as I suspect we need to either need to send the block off to be calibrated.
Any comments are appreciated.

I have just moved to a lab where they have recently had their calipers callibrated. Now they have sourced a rectangular piece of stainless steel (home made gage block), drawn on lines in permanent marker so that there are 3 locations of differing measurement that are always made in the same place, then carried out repeated measurements on this home made gage block with their recently calibrated calipers. This has given them consistant readings, and are now proposing to use this supposedly calibrated gage block to calibrate the same calipers in the future.
The calipers have been calibrated and have shown a measurement of uncertainty of +/- 0.0161mm. The item that we want to measure with the calipers are sieves, with the smallest diameter to measure is 4mm, and according to the procedure needs to be measured within an accuracy of 5%, which is 0.20mm. Now usually I go by the theory that anything that calibrates an item needs to have a count of at least 1/10th of the item being calibrated. However in this case, we dont need the calipers to be that accurate as they only need to be accurate to 0.20mm.
Can someone please confirm whether this method is acceptable in ISO 17205, or as I suspect we need to either need to send the block off to be calibrated.
Any comments are appreciated.

