There is not enough discussion of bell knife skiver presser feet, beyond the different lengths. I thought deburring and mirror polishing feet of any origin would be enough, but there seems to be more to consider.
I have many inexpensive presser feet from China that I have polished to a mirror finish. These work fine for edge skiving but do not necessarily give the best results for panel skiving. Most of these presser feet seem to have a steep beveled curve that provides full contact with the leather just before the knife edge.
From observations of online videos, it seems that people who are getting more reliable results panel skiving are using a presser foot with only a very slightly beveled curve, almost a flat curve.
I hope we can use this space to share experiences with and pictures of presser feet that work well.
A good test is to be able to skive reliably to 0.5mm without tearing. I think I have been able to accomplish this by flat filing my inexpensive presser feet, polishing, and then using Nitto tape.
Here is master skiver Iwabuchi san showing how he shapes his presser feet. I have started filing a very slight flat surface to the toe and heel of my inexpensive presser feet (confirmed results still pending), but nothing to the extent that Iwabuchi san does.
I'm beginning to think that the feet with the steep bevel might be intended for use with stone or steel feed rollers.
Here is a picture of Nippy presser feet. The curve is only very slightly beveled, and the toe and heel are less pronounced.
Here are two of my inexpensive presser feet. The one on the right has much less of a beveled curve but still more of a beveled curve than more expensive presser feet that seem to be used often on more expensive non-Chinese machines. This presser foot does seem to be more reliable than the foot on the left, which has a steeper bevel. Both of these presser feet still need to have the toe and heel filed down just a bit, and I need to do a more proper comparison, as these two feet are of different lengths. In my orders from China, I seem to be getting more of the feet with the steep bevel, even when listing pictures show a foot that looks more similar to the foot on the right.