Scott 552...perforation Question.

Hi guys...I collect American stamps only after Canadian obviously, but I am having trouble understanding how or why Scott rounds off perforations..

As you can see from the picture below, my stamp is perf. 11.3 x 10.4.
Scott says perf are...

11.0 x 11.0 - 552
11.0 x 10.0 - 578
10.0 x 10.0 - 581
11.0 x 10.5 - 632

Cant figure out which one it is..???

Thanks, Robert

wert, these come in flat and rotary plate versions. 19.5 x 22.5 cm is the rotary press design. 552, flat plate, is deep green and can probably be discarded as a possibility. (Your stamp doesn't look deep green to me at least.) You're probably looking at a 632.

(Watch me be contradicted!)

KGB...I did lighten them up to show me the perfs better, but you are probably correct..Thanks.

Robert

Your perf measurements come closest to matching those of 632. And I too have been irritated at times by Scott's practice of rounding perf measurements.

They should at least go to quarters in perforation measurements.

JLLebbert...jogil
You think like I do...Rounding off perfs is wrong..In my Newfoundland Specialized catalogue there are some stamps with 11 different perfs...That to me means 11 "DIFFERENT" stamps..And it should be the same way for American and Canadian stamps.

Just my opinion

Robert

To be fair, when there are multiple stamps of the same design with different perf measurements, Scott will usually be a bit more accurate. But not always. Occasionally the rounding on similar issues will even seem to be a bit inconsistent. But, for the most part, rounding is done when confusion between two or more similar issues is unlikely. But I find the practice annoying nonetheless.

Please keep in mind that a conventional perforation gauge is not a measurement tool. Use of the word "measurement" when referencing perforations is not useful unless a gauge like the one on the US Specialty Multi-Gauge is used. But, it doesn't really help because US specialists use the Kiusalas gauge, accurate to the nearest .001 inch. The Multi-Gauge also includes Kiusalas gauge.

The machinists who built the perforating equipment used for 10th and early 20th century US stamps did not use the metric system. Perforation pin spacing was set up to the nearest .001 inch.

Try hoining the joining the United States Stamp Society. Back issues of the "US Specialist" are accessible to members on the Internet. No more guessing.

Clark

With regards to the U.S. Kiusalas perforation gauge, wasn't 11-73 found to more accurately be 11-72.5?