Repartee wrote:

Does anybody know if the IBM electrics with the side magazines can be made to use ordinary ribbons?

Why, why, why? As you know the "side magazines" are for carbon ribbon, a one-way system without reverse since carbon can only be used once. The ribbon travels from the supply side to the the take-up spool, and converting it to a two-way system would involve a lot of work and the custom fabrication of many parts (I assume that it's possible, because if you throw enough time and money into almost anything, it's possible). Then there's the issue of the ribbon's size: the carbon ribbon is narrower, so the entire ribbon path would have to be altered, and most significantly a new vibrator made.

What would the motivation be to convert a carbon system? The longevity of a standard fabric ribbon is many hundreds of typed pages, and it's quick and easy to replace, so there's no cost-effective or practical advantage in undertaking such an arduous exercise - unless of course it's just for the fun of it, for the challenge of making it happen, to satisfy your inner MacGyver. I would applaud anyone for doing it, and maybe they could market conversion kits (surely they'd be able to sell ten or so of them); personally, I'd rather spend that time typing. 
 

I have seen at least two IBM Model B machines so outfitted (one I still have--a 1956 model), and one IBM Model A Executive I once owned that I converted myself.  I even soldered the extra pieces on the vibrator to make it work.  Then I bought an already factory outfitted machine and used its vibrator on my own conversion, since mine was a little crude.  It's not as hard to install a fabric ribbon on a Model A or B as you would think.  Now, the jury is out on any conversion on a Model C or Model D, but I have seen a Model C with the old-style vertical sawtooth-type ribbon spools.  I may do a little further digging and see if I can convert my 1962 IBM Executive the same way.  There is a problem with IBMs that have small print--especially Executives.  That is that fabric ribbons can make the small print tend to blot and not be as readable as when they are using carbon ribbon.  Outside of that, it's a doable project on Model As and Bs.  I'll let ya know if I can do the same with a Model C.

The vibrator of the IBMs that were equipped with dual-ribbon capability had 4 slots--two large ones on the inside and two small ones on the outside, higher up, so that the top of the carbon ribbon was at the same height as the fabric ribbon.  The reverse mechanism, as I remembered, was taken out of a fabric ribbon machine, but I had to (and this was a quick-and-dirty) super-glue them into the little holes they went into.  It worked, and everything stayed and functioned.  I couldn't tell you everything I did step-by-step because I did this about twenty years ago, but I can imagine I could still do it today after I study how I did it the last time.  Like you said, IBMs were built to accept either ribbon mechanism, or with the special vibrator, both mechanisms at the same time.  I found this out to be true even in Model A IBMs.      And as for the proportional spacing, there are no adverse effects on how the ribbon is advanced.  If anything, the cam that advances the carbon ribbon also advances the fabric ribbon.  But you can't have both ribbons loaded at the same time.  You have to either load the carbon or the fabric ribbon.  About the only problem is that particularly with small print, the fabric ribbon, especially if it's fresh, will tend to make the letters look blotted, so it may not be ideal for all Executives.  The proportional spacing in general works very well and seems to be as reliable as their standard spaced typewriters. They are quick in response, the touch is great, and the print, though not always typeset quality, is quite readable and beautiful.  They are more complex than a standard-spacing typewriter, but once you get to studying them and how they operate, it's not as bad as, say, a Selectric to understand.   In fact, I have seen and owned many more IBM Executive typewriters than any other brand of proportional spacing machine.  I even have some waiting until I actually have the time to go digging into them to getting them to working like they once did.

TypewriterKing wrote:

I wasn't sure what you meant by how well does the proportional spacing worked. I hope I answered your questions. Please let me know if otherwise.

Thank you sir! You packed a lot of information into that post!

What I meant about the spacing is I wonder how effective it looks on the page. Regarding filling I have noticed that elite type is more finicky than pica about the ribbon inking, I've also noticed that the same ribbon can give different results on two different elite machines: one will fill in the letters hopelessly even though the type is clean, and the other will work fine.

As for the effectiveness on the page, the Executive gave any letter a dramatically professional appearance.  The ribbon mechanism on the Executive has a feature that advances the ribbon further on bigger letters than on the smaller ones.  It would do the very same thing with fabric ribbons as it does with carbon ribbons.  It is automatically triggered when you type a bigger letter such as M or W.