Weird Indentions On This 2c Washington Coil

It's amazing the thngs you can see when looking at a common stamp under magnification.
I ran across this 2c coil on one of my 2 x 4 cuts. There is a strange line of indentions across the upper portion of the stamp. Under magnification they look like a washboard, measure about 4mm high and run across almost the entire width of the stamp. My first guess is it's from some kind of knurled roller in the stamp vending machine, that pushes the stamps out. I'm sure it's probably nothing to get excited about, it's just something I've never seen before.

Many vending and affixing machines left gripper marks on the stamps.

Russ, thanks! I knew there was a term for it. Did a quick topic search here and found a few threads mentioning gripper "cracks", but those seem to refer to something in the printing process.

I don't think that this is a subject that has previously been addressed here.

All vending and affixing machines needed to advance the stamp coil the correct distance of one stamp. Below is an example from a Schermack vending machine. This is just one of many methods that were used and this may not be the type that was used on your stamp. Hopefully this will explain the concept better.



When the handle wqs turned the feed gripper would rotate counterclockwise over the pressure wheel advancing the stamp coil. A cutter blade (not shown) would cut the stamp from the coil allowing it to slide down the chute to a tray. The feed gripper had serrated teeth to engae on the stamp to ensure that it advanced the proper distance. What you see on your stamp is the impression left by these serrations.

Schermack also used a design with cam actuated serrated fingers that also produced a similar impression. Brinkerhoff also produced vending machines using a serrated wheel to feed the stamps. Other companys also produced vending machines but I don't know the specifics of their design.

I hope this helps in understanding the gripper marks.

Yes, that helps greatly! thanks!
Great information there to go along with the technical drawing.