Unable to change Stitch Length on Industrial Singer 139w100

[Kellyo]

I ended up with this awesome long arm industrial machine a few days ago and it seems to work great. Only problem is I cannot get the stitch length adjusted no matter what I try. It's at 9/inch right now and I need it around 5. After a lot of digging I've discovered it's a Singer 139w100 from 1940. It seems to be rare so there's no manual anywhere for it, just a parts list. I've referred to a couple other manuals of similar machines but they haven't helped much.

The spindle in the handwheel is hard to move but rotates how it should and goes in and out of the machine with out issues. It doesn’t seem to have any effect on stitch length, the numbers on it seem meaningless right now. In the #1 image I have the two zero’s on the plates lined up - a video I found explained these needed to be aligned to reach the longest stitch length. In #2 the adjustment screw is tighted all the way, it seems to have no effect when I tighten or loosen it. It came without a set screw on top of it. I took the screw out in picture #3 because maybe that was locking the adjustment in place? Also no help. And in #4 the spring is held pretty tight under the set screw but adjusting this still doesn’t change anything.

Is there something I’m missing? My machine has no buttons to press for stitch length adjustments like others I’ve seen. I saw in another manual something about adjusting the feed dogs simultaneously.. if that’s the case, I can’t figure out how to do it on this machine.

Any help would be greatly appreciated. Also any other info on this machine would be cool, I can’t find much online but there has to be a few more out there somewhere.

[friquant]

You may have to disassemble some of the pieces to understand how the spindle operates the stitch length regulator. Along the way make sure the pieces are lubricated. 

I'm not finding any manuals at all for this model. Do you mind posting links to the video you mentioned, and to the parts manual?

[photonashville]

Quite a few things to go through here. This is one of the earliest styles of stitch length adjustment for anything that mimics the 111w series. I have a Singer 112w two needle and a Singer 153W cylinder arm both with this same older style stitch adjustment.

First, where that hex nut was welded (not original but can certainly help) for your machine use a socket and turn it COUNTER CLOCKWISE to lengthen the stitch (it will actually tighten into the machine) and CLOCKWISE to shorten the stitch (it will move away from the machine and also how you fully remove the pin). Any machine with this adjustment has threads opposite of righty-tighty-lefty-loosey.

Second the hidden threads are very delicate and over time many can fracture. It's wasn't a bad design but unless properly oiled over its history, the threads will break when forced too hard. They badly need to stay lubricated. 

My suggestion is if you can remove that end knob (with next nut) completely to remove the long pin, you will better understand what you are dealing with. Then clean and oil those threads. My understanding is that this style only allowed 4mm stitches back then and that is the case for both my machines.

I will find the manual page that explains this design and attach photos of the pin etc.

Edited September 1 by photonashville

[Kellyo]

I've had it apart quite a few times now to inspect everything and see how it works. Everything is lubricated. It feels like the adjustment screw isn't even contacting the spindle end but there's no reason it shouldn't that I can see.

Parts List - https://www.supsew.com/download/Singer/Singer 139W101.pdf?

Blog Post that was helpful and a couple good photos of the inner workings - 

 

[photonashville]

Oil heavily between the two parts marked in red and blue around the full rotation. These need to move freely but independent of each other for proper stitch length adjustment.

Additional photos show the pin removed and the threads when exposed.

[Kellyo]

13 minutes ago, photonashville said:

Quite a few things to go through here. This is one of the earliest styles of stitch length adjustment for anything that mimics the 111w series. I have a Singer 112w two needle and a Singer 153W cylinder arm both with this same older style stitch adjustment.

First, where that hex nut was welded (not original but can certainly help) for your machine use a socket and turn it COUNTER CLOCKWISE to lengthen the stitch (it will actually tighten into the machine) and CLOCKWISE to shorten the stitch (it will move away from the machine and also how you fully remove the pin). Any machine with this adjustment has threads opposite of righty-tighty-lefty-loosey.

Second the hidden threads are very delicate and over time many can fracture. It's wasn't a bad design but unless properly oiled over its history, the threads will break when forced too hard. They badly need to stay lubricated. 

My suggestion is if you can remove that end knob (with next nut) completely to remove the long pin, you will better understand what you are dealing with. Then clean and oil those threads. My understanding is that this style only allowed 4mm stitches back then and that is the case for both my machines.

I will find the manual page that explains this design and attach photos of the pin etc.

I've already taken these components apart quite a few times and lubricated everything. What welded hex nut are you referring to?

[photonashville]

That looks like a welded hex nut not original to these machines. Someone added that for better grip of the adjustment pin. Or maybe added for needle positioning?

Edited September 1 by photonashville

[Kellyo]

3 minutes ago, photonashville said:

That looks like a welded hex nut not original to these machines. Someone added that for better grip of the adjustment pin. Or maybe added for needle positioning?

Oh yes, that's for a neede positioner that I took off while messing with the machine. I've taken that out a few times and nothing seems to be obviously wrong expect the end of the spindle may have the tiny tip broke off. Not sure how much that would effect the function since the adjustment screw should still be coming in contact with it.

[CowboyBob]

It is really pretty simple,you need to turn screw BB in to make the stitch longer.Does your screw have the pin that's about 1/4" long on the end?If not it won't go in deep enough to hit the pin.

We have new screws for the one marked marked BB in stock if you need it.