Vibrating presser foot tension spring adjustment thumbscrew

[chrisash]

Trying to understand the purpose of this part "Vibrating presser foot tension spring adjustment thumbscrew" noting in general instruction operations and the US Navy instructions just confuse me,

So my question is when and why should i make any adjustment by turning it

Many thanks, it sews well as it is so don't want to play around with adjustments just for the sake of it

[Constabulary]

You have a Singer 111 - right? There are 2 thumb screws. I have set both to very low pressure and only when I feel the rising needle is lifting the material I increase the foot pressure. Lesser foot pressure means fewer foot marks on the leather. But the thicker the material the more friction you have between material and neelde and the more foot pressure you need - basically.

Edited December 13, 2020 by Constabulary

[chrisash]

Many thanks

[duckySews]

HI!

I also posted this on another post...hoping to reach more people...

Finally got my 111w155 set up and doing the once over and she is missing the same "Vibrating Presser Bar Thumbscrew" knob and the spring and shaft too!!!

 

She seems to sew just fine...do I really need it???? I can't really see how it puts more pressure on the needle foot.