Obverse die match 2, eastern mint denarii of Severus Alexander,

[mix_val]

Here are three more specimens with identical obverse die that I have just added to my Eastern denarii album.
https://www.forumancientcoins.com/gallery/displayimage.php?pos=-167735
https://www.forumancientcoins.com/gallery/displayimage.php?pos=-167734
https://www.forumancientcoins.com/gallery/displayimage.php?pos=-167733

I thought it interesting to note the variation in weight (2.85, 3.02 and 3.45g) and die axes (12h, 6h and 12h) for coins struck at the same mint and roughly the same time.
Because blanks are made by hand, their weight could vary significantly provided that a required number of blanks per roman pound was met.  That may be the reason for the extremes in weights when one had too much or too little silver to make the last blank.
Die alignment was not strictly enforced (at least in this case).  It would seem very simple to design the anvil die and hand-held die so they could only fit together with axis 6h or 12h.  An ellipse setting for each die would do the trick and would make the striking of coins efficient.   Is there any evidence for this?

[curtislclay]

Again interesting, and first-rate coins!

What do you mean by "an ellipse setting for each die"?

Unfortunately F. Diederik's new message regarding his A. Pius aegis sestertius refuses to load for me.

[mix_val]

Again interesting, and first-rate coins!

What do you mean by "an ellipse setting for each die"?

Unfortunately F. Diederik's new message regarding his A. Pius aegis sestertius refuses to load for me.

It's the idea that you can't fit a square peg in a round hole.  
If the obverse die was set in an oval recess on the anvil and the reverse die was set on the face of an elliptical cylinder (see below from Wikepedia), there would be only two orientations of the dies possible when they were fitted together for striking provided the dies themselves were oriented along the long axis or short axis an ellipse (see a and b below).  If one die was oriented on the long axis and the other on the short axis, they will be at right angles when struck.

I can't open the A. Pius aegis thread either for some reason