Lightening up presser bar pressure

[tielz]

I am learning to use my Pfaff 331.  It has the roller foot on it.  The machine is the 331-33, which came with the presser foot and it's presser bar.  Somewhere along the line it was changed to a 331-4 with the roller foot and presser bar that goes with it.  The manual shows no difference in the springs for these different presser bars.  

I cannot seem to get the pressure to lighten up enough to not put tracks in the leather as it sews.  I have tried unscrewing the nut on top until it is just on with the first few threads and it does not seem to make that much of a difference.  If the leather is smooth, it is going to get a design in it whether it likes it or not.  I cannot move the roller attachment higher up on the bar because there is a little bar stopping it.  Does anyone  have any ideas on how to change this?  Most replacement parts are obsolete for this machine, but I have found a few select ones like the outer spring for the bar and the presser bar and components for a presser foot (but no presser foot).  I have not ordered anything yet.  

Besides this issue, I really have no complaints.  She sews a nice stitch with 69 and 92 thread.  

[Pintodeluxe]

Welcome to the world of Pfaffs!  Most Pfaffs I've used have almost double the foot pressure (at the lowest setting) compared to other brands.  Short of drastic measures like replacing leaf springs and/or cutting coil springs shorter, I haven't come up with a solution.  

[Constabulary]

The machine has just 1 major tension spring as it seems. I would shorten the spring by 1/2" or a bit more deepening on how light you need the foot pressure.

EDIT:

Haven´t noticed Pintodeluxe´s reply

Edited October 9, 2020 by Constabulary

[shoepatcher]

Unscrew the top tension knurl screw.  Remove  the big tension spring.   Cut a couple of twists off the spring, put back in a te4st.  Tension still high at lowest setting, remove and cut more off.  For some reason, Pfaff putt these high tension springs into the machine.  Never had any Pfaff cylinder arm where I did not have remove the spring and  cut some length off the tension spring.

glenn

[Hockeymender]

Like stated above, cut the spring. 

[tielz]

Thank you all!  Is there a certain place to cut the spring or anywhere along it's coil?  

High tension is an understatement!  I cannot even put my finger under it at the most "loose" tension. 

[Constabulary]

Donn´t you have a wire cutter?

[tielz]

I do, yes.  I guess I was thinking that a sharp edge would be left, but I can always file that down. 

[shoepatcher]

start at the bottom and work up form there, taking 1-2 coils off at a time.  I prefer to use a Dremel  with a cutting wheel on it.

glenn

[tielz]

On 10/15/2020 at 7:59 PM, shoepatcher said:

start at the bottom and work up form there, taking 1-2 coils off at a time.  I prefer to use a Dremel  with a cutting wheel on it.

glenn

Thank you!  I did not even think of using my dremel.  I will do it this way.  

[Kcstott]

Cutting springs only reduces preload. but the spring rate actually increases. you are reducing the number of active coils and that increases the spring rate. 

What should be done is pull the spring out and measure it. then order a new spring from say McMaster Carr with either smaller wire diameter or more coils per inch or both.