US Scott 490 With 9 1/2 Perf???

Going through a batch of these 1 cent stamps and found this CV perf 9 1/2 rotary coil pair. Naturally, there is no 9 1/2 perf for this issue. Any ideas as to what this might be, or why the perf is so off on all 3 sides of the vertical pair?

Chaulk... kindly load a nice, clear scan for us to view...

The coil on the left measures a nice 10 perf, the coil on the right is the 9 1/2 perf. No scanner so I took a picture.

When I copy the middle perfs of the left pair, they match nearly identical to the middle perfs of the right pair.

When I look closely at the 3rd stamp from the left, I see a large triangular shadow underneath it. Also, I notice how non-square the 3rd stamp is in your picture. Having the left hand side of the 3rd stamp raised off of the surface plane would make it seem to be a lower perf count.

Please post a picture of the open perf edge of the 3rd stamp against a perf guage, or in the same vertical plane as your other perf 10 examples.

Is this what you wanted? Sorry a bit blurry.

These rotary press coils are generally perforation 10 but can be either Kiusalas 10-80 = 9.84 (mostly) or Kiusalas 10-81 = 9.72 (rarely).

Also, metallic perforation gauges measuring only half perforations are not the most reliable of perforation gauges.

It appears that the coils that you show on the left are flat plate coils which measure perforation 10 (Kiusalas 10-79 = 9.97).

Flat plate coils were perforated by different perforators than rotary press coils which makes their perforation measurements slightly different.

Slightly different perforations measurements can help to distinguish flat plate coils from rotary press coils.

Thanks for the comments. I just completed going through many 490's and actually found 1 more with the closer to perf 9 1/2 situation. So apparently it's a rather common occurrence for this stamp. Yes, I have ordered a better perf gauge. Although I have to admit the 50+ year old metal one did work fairly well.

I think that the two rotary press coils that you found may be Kiusalas 10-81 (9.72) which is scarcer than Kiusalas 10-80 (9.84).
Generic gauges are fine for separating 1/2 perfs in general but for separating closer perfs in 1/4 or 1/10 a more accurate gauge is needed.

Please use a scanner. The picture is unconvincing. A small hole variety (496a) of the 5 cent coil exists but the hole spacing is the normal .080. I have yet to see a convincing 10-81 perf rotary coil. The approximate gauge does exist approximately between some of the holes in the perf 10 row seen on the flat plate perf 10 top or bottom variety.

Clark

Sorry, no scanner. I have ordered a better perf gauge so when it comes I'll post the readings that are hopefully more accurate.

Received my new perf gauge and took some new measurements. The perfs were 10-81 Kiusalsa and 9.7 on the analog scale.
Thanks again for the inputs.

It's good to hear that the perforation mystery has been solved.