Macybaby

This is a rough explanation - and I'm not considering per 1890 machines - only those after the machines had evolved to what I'd call the "modern" look (I'll leave the early ones to Steve H!).

Singer has the type we are most familiar with, the presser foot bar is round, and then flattens out at the end and has a screw hole in it - and a side clamping foot is attached with a screw into that hole.



While there are other exceptions - the majority of the other US made machines had a bar that was round all the way to the end. With the early ones, the foot had a round opening at the top and slipped onto the bar with a screw to tighten against the bar.

Ignore the bed mount ruffler and only look at the foot - and how it goes up and the presser bar fits inside it.



The very early sets used bed mount hemmers and binder, so only the narrow hemmer and ruffler mounted to the pressure bar. The tucker was also bed mount.

Most of the "next generation" sets had some sort of adapter that fit onto the bar and then the different hemmers attached to it. Usually the ruffler and narrow hemmer were direct mount feet. Here are two adapters showing the hole the bar fits into - note they are not the same diameter.



I have several sets that have different style adapters - and if you lost the adapter foot, you could not use the others.



Then someone came up with the "top clamp" style adapter, where the feet slip unto the bracket and the clamp is screwed DOWN to hold them in place. I have sets that included this style adapter. The regular foot that came with the machine was still slipped directly on the bar, and often the ruffler was still this type.



I think it was not long after that machines started coming with the adapter already on the machine, so even the regular foot was top clamp. Sets no longer needed to come with an adapter and you could easily buy a replacement clamp for the machine if you lost one. At this point most tuckers were also mounted to the presser bar and not the bed.



The cardboard boxed sets are later, and almost always for Rotary machines. The only difference between them is the bed mount attachments, which is the shirr plate that works with the ruffler when shirring, and the underbraider. And later ones don't have the underbraider as they went to top braiding.

On the later style top clamp sets, there are many variations. I've not got through my earler sets that use the direct mount feet or other adapters yet - but for the later sets, so far I have
6 for Standard
1 Foley & Wilson
2 Eldredge (pre National)
1 Davis
5 National
2 Free (early)
3 Free/New Home (after combined)
1 New Royal (old style)
6 White
4 New Home (before Free combined)

Not all are complete sets - so I'm still looking - and some are the same except for a Rotary set and a VS set - so only the plates are different. And I'm always looking for the extra feet that weren't part of the basic set, like cording and zipper feet, embroidery feet, hemstitchers (feet and plate) buttonholers and other fun stuff.