Several of the Liberty issue coil stamps (Scott #1054-1059) are known with large and small hole varieties. Only Scott #1059A exists in a single size only and doesn’t have listings for large and small hole varieties. What are they and how do you tell the difference?
When the Bureau of Engraving and Printing (BEP) changed from 384 subject printing plates to 432 subject printing plates, they also changed the perforation hole size. Although both holes are considered gauge 10, they are slightly different. Because it was such a trivial change, the BEP and the USPOD didn’t make a fuss over it and announce the change to collectors. Therefore, some of these varieties are very expensive because it wasn’t until years later that specialists noted the differences and different catalog numbers were given to the varieties.
The easiest way to identify a large and small hole variety is with a pair of stamps. Yes, singles can be identified too, but it’s a little more challenging when you only have half of the hole to measure!
I’m familiar with two ways to tell the difference in the hole size.
The first way is challenging and requires a careful eye. Measure the width of a perforation hole and then measure the width of the paper between two perforation holes. If the size of the hole is greater than the size of the paper, then you have the large hole variety. If the width of the paper is greater than the perforation hole, then you have the small hole variety. Here is the catch. The difference in size is a mere fraction of a millimeter. You need a steady hand and a good magnifier to tell the difference. A tiny slip of the millimeter scale one way or the other and you will throw off the measurement.
The second way is easier. Sonic Imagery Labs created a product called the Precision U.S. Specialty Multi-Gauge. You can still find this on the internet for about $15. The gauge measures perforation holes and a whole lot more. Anyway, there is a special spot on the gauge that measures the large and small hole sizes. Just like using any other perforation gauge, if the holes on your stamp match what is on the gauge, that is the variety that you have. In this case, I think the measurements are much more precise when done correctly. I highly recommend using a gauge to be sure.
Technically, there is a third way to measure the hole sizes. However, you have to start with certified copies to begin with. If you had two stamps that were authenticated by an expertizing service (one small hole and one large hole variety), you could compare your stamps to the certified copies and see which one matches. This method though requires that you start with already certified copies though. Not everyone has access to certified copies though.
Some issues like #1054 don’t vary much between the large and small hole varieties. In these cases, both varieties are very common and the price differential is pretty small. However, a joint line pair of Scott #1056 (as of this writing) catalogs $3.50 for the large hole variety and $3000 for the small hole variety – almost 1000 times the value of the large hole variety.
The Liberty coils are still pretty common and readily available. You can even find entire rolls of coils for sale. The collector with the careful eye and a perforation gauge may make a discovery that pays off handsomely.