CStan
You know, you get what you get when you buy a single-iron wood plane. The mouth opening is the mouth opening. Obviously, there is no cap iron to bring to bear. One iron, one mouth aperture. That's it. Sometimes there is beauty in simplicity. Sometimes not. I guess it's beautiful as long as the planing is going well. If it's not I'm not quite sure what one would do except to insert one's thumb in a place where it doesn't belong and hope that somehow something changes.

I end up adjusting the mouth opening on my No. 5 probably more than any other plane. Maybe I'm just kidding myself that this has efficacy. Sure seems to work those times when I feel the need to close it down a little. I'm sure there are many who would chalk this up to me simply not understanding how to plane, the "proper" use of a jack/fore plane, and all of that. And they may be right. But I can still walk out to the shop and change the mouth aperture. If I feel like it. Whenever I feel like it. Cap iron setting too.

And all for about 45 bucks, used (I prefer "broken in").