Franklin Coil Straight Edge Test

I love the Wash-Frank series, but am flabbergasted like most at the number of faked perf 12 coils. I've seen multiple posts stating that the straight edges should be parallel.

I was wondering if there is an allowable margin for not being perfectly parallel with the straight edges?

For example, this stamp might be "close", but I would not say it is perfectly parallel. (sorry if the transulent quality isn't great, I'm using a cheaper version of photo software) To me the edges are slightly closer in the middle compared to top and bottom.

Looks suspect to me.
Don

Edges should be parallel, no variation that I'm aware of. Also, the rows of perfs. should also be parallel. The top row of perfs. on your example are running down hill right to left and not parallel to the bottom row. Some of the perf. holes in the top row are also mis-aligned from the rest. Questionable whether this is a good stamp as I see it. Others may have another opinion.

I agree with Al E. Gator/Dave that the straight edges and perf rows should be parallel to each other respectively. Do both straight edges feel the same? Are they rough or very clean cut?

Rotary stamps have aligned rows of perfs (i.e. matching in location top and bottom). Flat plate stamps have randomly aligned perfs from one side to its opposite, but can rarely align naturally. Aligned perf rows on flat plate stamps are very suspicious. Your stamp's perfs are not in alignment top to bottom which is a good sign.

The horizontal red lines in the image below are orthogonal/90 degrees to the vertical one. Perf rows aren't always parallel to the frame lines. We're just concerned that they are parallel with each other.

Both rows don't obviously fail the SRAIL test, but the top ones look worse, so maybe it's a left hand margin copy with perf added at top and cut away at right? It's possible that both rows were added to an imperforate stamp. Regardless, I agree with the others that it doesn't appear genuine.