USA Harding 2 Cent Perforation 11 Rotary/Flat Measurement

Does anybody know of a way to measure the miniscule 1/4mm difference yet? I have two such stamps 11 perforation that read 22.25 on a set of calipers, but fear the reading is not as exact as I would like it to be, because it's difficult to get the jaws on the edge of the design. I know the chances of finding two are remote, but never say never. Thanks in advance for any suggestions

Welcome.
Trying to measure is not a reliable method for identifying a rotary printed stamp. It is unfortunate that catalogs publish these dimensions and mislead folks into trying to use them to ID these stamps. For further information on IDing printing types for this era US stamps see these articles
http://stampsmarter.com/learning/Ma...methods.html
http://www.stampsmarter.com/learnin...arities.html
http://stampsmarter.com/1847usa/ByYear/1923.html

Don

Thanks Don I'll have a look shortly, appreciate your response

I use a "Precision US Specialty Multi Gauge" for my measurements. The first 40 mm has markings on the quarter-mm scale, and half-mm thereafter. Even with the half-mm markings you can easily interpolate at the quarter-mm scale. This photo is from Mystic. It may be slightly different from mine.

Don, please explain your assertion.

Regarding unreliability, there are two reasons I can think of.

Either people are just naturally bad at measuring without lots of practice so that repeated measurements of the same distance varies too much for the measurement to be useful.

Or, the actual dimensions of flat plate/rotary images vary so much that the distributions overlap too much for them to be distinguished.

If it's the first reason, then there's a glimmer of hope. But if it's the second reason, then there's no getting around it.

Scott 613 is a Scott 612 stamp with gauge 11 perfs instead of gauge 10 perfs.

Yes, there's that, too. Thanks, jogil, for pointing that out. If a flat plate/rotary can be distinguished by their perfs, then do that. But if the primary distinguishing features are inconclusive, then what? That's what I'm on about!

edit: changed "perfs are the same" to "primary distinguishing features are inconclusive" for clarity.

rmatossian,
The dimensions and tolerances are far too great to be used reliably.

Note that confirmation bias also comes into play, influencing users as they measure. Inexperienced (and some experienced) hobbyists see a rarity in a catalog, see the dimensions, measure a stamp hoping they have a rarity, and become 100% convinced they have a rarity. Then many of us invest untold amounts of time trying to undo their misunderstandings. I think that if catalog publishers had to invest their time on this issue that they would clarify their publications.
Don

rmatossian: Scott 612 is a rotary press printed stamp so that its outer frame dimensions should be the same as those for Scott 613 but not the same as those for flat press Scott 610 (and 611).

Boy, Howdy! We are fantastic at motivated reasoning.




Thanks for this reply, but your reasoning is still not clear to me. It sounds like you're saying that the difference of a half mm is too small to be measured reliably because of poor measuring, whether caused by bias, inappropriate or defective tools/technique, waning eyesight, or whatever. If that's the case, I disagree completely, because all those sources of error can be overcome, say by using a microscope or some kind of automated measuring device.

On The Other Hand

You might be saying that there are some instances of a rotary that is actually the same size or smaller than a flat-plate counterpart. For example: flat plate = 19.5 with tolerance plus or minus 0.3 and rotary = 20.0 plus or minus 0.3. What if you measure it as 19.75? This is a problem which cannot be remedied, and if this is what you're saying, then I agree with what you said about catalogs.

I realize flat plate vs rotary can be distinguished in other ways, but this discussion was originally about measuring small distances generally.

Please go back and read the hundreds of threads where this topic has been discussed ad nauseam. Additionally, if you had read it the link I gave above, you would have had your questions answered. Please go back and carefully read this article http://stampsmarter.com/learning/ID...arities.html
Don

Don,

You assumed I have not read the linked article. I have read it, more than once, very carefully.

Article says:




To use a "common" ruler is imprecise, and Vernier calipers, if I am not mistaken, are intended to measure thicknesses, not distances. Since the ranges given do not overlap, the reason for not measuring does not apply if an appropriate device is used.

Article also says:




Are these paper grain differences (booklet vs sheet vs coil) the source of the ranges? And, if so, do the ranges now overlap? (Since booklet stamps, sheet stamps, and coil stamps all started out as sheets I always assumed that they were made with comparable paper.)

I admit I have not read the hundreds of threads, but I have read some. Typically someone tries to use a yardstick or something like that to determine what stamp they have, then this remarkable community responds with mountains of fantastic advice about setoff, perfs, ink smear, and the like.

Again, Don, thanks for your patience with my questions. It seems you are always willing to expostulate freely with people, and your posts portray your thoughtfulness.

The section I was referring to was this one;


Clark Frazier has a number of post in this community and is also noted in the article. He is currently the leading expert on Washington/Franklin era stamps and their production; I take his opinion to the bank.

The reason that dimensions are favored by some hobbyists is because they appear to be definitive but more importantly they appear to be easy. It is certainly easier than bothering to learn how the flat plate vs. rotary printing processes of the era. To be honest, once a person has enough experience you can typically ID and sort flat plate vs. rotary stamps by look and feel.

Lastly, this community gets an average of 2 inquires per week from folks who think they have a rotary rarity based upon dimensional criteria. While many of these threads go on for a number of pages (the original posters sometimes push back and argue for days) I think the average number of replies is about 5 posts per thread. So that's about 500 replies per year on this topic and if each reply takes 5 minutes then that is 40+ hours per year that is spent trying to clear up the misunderstandings.

And this is just one community, consider the time that dealers, appraisers, and certification experts have also invested in the same issue each year. And then multiple this efforts over the decades that our hobby has dealt with this issue. I think that it is reasonably conservative to say that literally thousands of man hours have been spent trying to undo the misidentification of rotary press stamps based upon dimensional criteria.

By any account, there is extraordinary amounts of time wasted on this topic. So if I have come across as impatient on this topic, please understand.
Don

We all do things that waste man hours.

Sorry to Clark Frazier for removing his name from the quote.

True, I waste my own man hours sometimes but I do not waste other people's time unless I am paying them. Donate button is on the left hand side of the page!
Don

OK, done!