Overview Of Minimum Sizes For Coils And Imperforate Stamps

Hello,

quite often I see or find stamps that have perhaps trimmed perforations to be a coil or imperforate. I read in several topics here in the forum when somebody mentioned a minimum paper size for such a stamp so that you can check whether if it's a true coil or imperf. I don't find those threads again here in the search, and I hope that somewhere there exists some kind of overview.

So is there an overview where you can find the mininum vertical and horizontal sizes in mm, for example for the issues 1902, 1908/1910 and 1912/1914 ?

(Or is it always the same minimum size or different for each issue and stamp so that there is no overview?)

http://www.stampsmarter.com/learnin...keCoils.html
Don

Edit; You can also find info on imperf size on the site; "#315 must measure at least 21.5mm x25 mm to be considered legitimate"

But note these are not hard and fast rules that apply in 100% of the time. Trying to use measurements as a way to ID US stamps is a slippery slope.

I had discussed some of Bill's comments with others and told it was not as black and white on issues.

Bill used the '95% of the time' qualifier; I do not know if this is accurate. I also am not aware of any significant studies which have been done to produce a quantified analysis of US stamp dimensional sizes. If someone can point me to a reference I would like to update Stamp Smarter.

Experts like Clark are able to navigate the W/F because they have a deep understanding of the production history of the stamps. They are able to include and assimilate dimensional info into the big picture.

But for us mere mortals, using dimensional information can be dicey.
Don

Studying the edges is valuable; learning what genuine coil edges look like. The devices used to create them were sharp but not SHARP. Not like a razor or scissors cut. Most fakes are too sharply cut and are uneven.

Thank you all. Yes, I know there are other aspects to consider when you check a coil or imperforate, but (as Bill also shows as it is the first point in its list) the most easy and quick check is just the size. If the size is totally wrong, it's done already. But your other hints also help me.

Still then two questions about the sizes:
- is the rule "horizontal coils are 25mm, vertical are 21.5mm" valid for all these issues, so the issue 1902-1908 and all W-Fs from 1908-1914?
- is there a rule "imperforate are minimum 21.5mmx25mm, and this also for all the mentioned issues?

thank you again.

The short answer is no. However, common sense should prevail. Once an imperf single has been cut out of a sheet, it is not be possible to be 100% sure that the stamp was from an imperf sheet. The "dimensions" given above assume that the stamps were separated evenly on the margins. The height and width are approximately the design size plus half the distance to the next stamp on the sheet.

Most fake imperf stamps are used. Most have small margins or show traces of perforations or may not have ink on the edges from the cancelling device. Some used imperf stamps, like 315 would be exceedingly rare in any case because the remaining supply, not used for private perforations was sold to collectors.

Coil height and widths are nominal. For reasons unknown, 5 cent flat plate horizontal coils are usually on the short side. Imperf coils were perforated to resemble perforated coils. Almost all fake coils trimmed from sheet stamps are used. Most coils with fake perforations from imperf coils or sheets are unused. Coil edges have known characteristics, unlike imperforate stamps that were cut by end users.

The bottom line is that coil dimensions are not at the top of the list of characteristics to be checked. Coil edges and perforations are more important. Most trimmed fakes are so bad that the edges won't appear to be parallel or the margins will be razor thin.

It is better to think about the business problem facing the Bureau. They had difficulties producing enough stamps at acceptable quality Rapid expansion of commercial mailings and use of affixing machines required coils. Flat plate coils and imperforate sheets were interim products needed until rotary press coils could be reliably produced. The ten year transition period for coils and then a longer transition period for sheet stamps resulted an a technological revolution in how stamps were produced.

stamperix, per cfrphoto, take the measurements to be nominal as a protection factor. Genuine stamps that are smaller than nominal certainly do exist. Proving that can be tough. There are line pairs that cannot exist cut from sheets; so long as the line isn't drawn in, any size is acceptable, though checking for a reperf on one side or the other (or even both) is still necessary.

A coil single on cover where the cancel(s) or markings covers enough to help prove no trimming has been done does not have to meet the nominal measurement. That a cover has a corner card or ad of a company that was known (by other covers) to have used coils is also a supporting factor.

Many collectors figure buying W/F coils at 10% of catalog covers them. Nope. If you look at the price of (say) a damaged pair of the sheet stamp they came from, the pair may not be worth even 2% of the coil pair.

thank you both. it's always a nice reading when you two share your knowledge. I understood all this better now.

I assume now that - rule or not - all this is concerning all the issues I mentioned and there was at least not difference in the spacing between the designs on the paper during this time, so that I can take these measurements as a additional help for coils at least.

About the imperforate stamps just one last question appears - is it correct that for the vending & affixing machine perforated stamps they weren't cut by scissors and so you could take the measurement I gave above as a rule of thumb for them also?

From 1909 to sometime in 1912 plates with 2 and 3 mm horizontal spacing were created in an attempt to counteract paper shrinkage. Later "A" plates reverted to uniform spacing. Check the Scott Catalog for listings of blocks or pairs with 2 or 3 mm spacing.

I would hesitate to use coil height or width as a "rule of thumb" without corroborating evidence. Size by itself is never enough to declare a coil good. It may be used for imperf singles to assign a level of credibility, but size alone is not proof of genuineness. Some Bank Note singles exist imperf with large margins but are not accepted because no pairs exist. Finally, tread cautiously with privately perforated coils. Some insight may be obtained by reading Steven Belasco's "Guide to United States Vending and Affixing Machine Perforations 1907-1927".