Presser foot pressure

[Gymnast]

I lately made a study of presser foot pressure and made a little video about the result. I have noticed, that the range of foot pressure, that you can set on a sewing machine, is normally not a public specification by the manufacturer.

So I measured the foot pressure, presser bar friction and the stiffness of the presser bar spring on seven vintage household sewing machines.

I know, that I need about 25-30 Newton (5-6 lbs.) foot pressure when I sew some heavy vinyl or webbing on my drop feed machines. And a low pressure about 5 Newton on soft fabrics with thin thread. I noticed that some of my machines are not able to provide that as it seems like they were made from factory. But some of them can get modified.

I guess most Leatherworkers do not need to know the figures of foot pressure of a machine, and you will always be able to set it as you need by some test sewing. But perhaps some of you like to see  some reference to measured foot pressures and how machines can vary in this regard. It is easy to measure foot pressure.

I studied some previous threads on Leatherworker about this subject, and I think this one do provide some extra good information:
https://leatherworker.net/forum/topic/78816-cowboy-cb-4500-waliking-foot-pressure

[Gymnast]

Well, already my post from above is 4 years old.

At the moment I do some test on a Dürkopp 291 industrial combined feet sewing machine. I have tried to measure the presser foot pressure and on its minimum setting, it provides a pressure of 87 N (8,9 kg or 20 lb). Maximum is 220 N. To me this pressure seems very (and too) high. But the machine works fine on tarpauline.

The picture below show how it is measured.

I have tried to look up in specifications and service manuals regarding this and other similar sewing machines and have not been able to find data. So I hope, that you perhaps have seen that.

AI answer that this pressure is 5 to 30+ Newton on industrial sewing machines.

I found one newer Janome HD9 household sewing machine, with a specification up to 11 lb (5 kg or 50 N):

https://www.janome.com/product/hd9-professional/#machinespecifications

I hope that someone else might have seen this pressure specified on another sewing machine or perhaps have measured it.