Wide Stamps Explanation

I have a 156 and 185 which have a second image and no perfs on one side. The 156 was sold as a 156f. Can someone comment on how this condition occurred and is it common?
Thanks,

"The 156 was sold as a 156f"
Yikes. To be a 156f, you have to have 2 full designs, not one and a sliver of another. The ones you showed are called a margin straddle - it os from the edge of a pane (which for these issues always have a natural straight edge) and is miscut enough to show a little of the pane next to it. While not real common, hardly rare (although your 5c shows mare of the next stamp than usually seen on these miscuts).

I think those are very interesting and collectible stamps, and I wonder how this can happen in the printing process, perhaps someone could explain a little. Why should the cut be made so badly, and in addition not straight?

These are called "straddle margin" examples. This is where the sheet was cut into panes before being shipped out to post offices. Precision was not always employed.

So this was made with scissors?
And along the guide arrows?

To elaborate on revcollector's post. There are several steps in the production process, in the case of your 2 stamps:
1. The printing process occurred normally.
2. The perforating process occurred normally.
3. The cutting of the press sheet into panes for retail sale was slightly off.

Yes, the cut should align with the guide arrows. The point of one arrow appears at the top of your 5 cent stamp. I am sure these were cut in a stack of multiple sheets at once, with this sheet not being aligned perfectly with the top sheet. Also, no doubt cut with a large industrial-sized knife machine of some sort ... not scissors. Relatively common and within quality control standards of that era. Interesting, but not valuable beyond a normal stamp.

Thank you for the explanation, I understood it now better, especially the possibility that more than one sheet was done at once. Unfortunately those are not my stamps, but I think the OP will be glad to know all this about his stamps.

Thank you for the clear explanation. I can assume that there were 10 of these stamps on this particular sheet and the opposing 10 stamps have a straight cut on the left!

Bureau sheets were split into half-sheets or panes by the perforator. A circular cutting knife was located between the perforation rings. It seems likely that 19th century sheets were perforated horizontally and the vertically, cutting the sheet into panes in the same step. Would it would be possible to cut a stack of sheets into panes with a guillotine without rupturing fragile perforations?

It is difficult enough to understand 19th and early 20th century stamp production when documentation is scant. Were small snippets of information frequently filling space in publications, like MeKeel's, fact, fantasy or guesswork? It is difficult enough to refute the myth that sheets of stamps were grilled more than one sheet at a time by the National Bank Note Company in 1870 and 1873. Why create new ones?

martin53545...They even done the same thing with Canadian stamps.