Pfaff 545 Identification and tension issues

[Gryning]

Hi all, 

I Recently got my hands on an old Pfaff 545 and since I needed a flatbed machine for sewing leather I thought this was the machine I didnt yet have. The prevoius ownere hadn't sewn  leather on it and did mention it skipped some stiches sometimes which made me think it would be a calibration job more than anything... I might have been wrong. 

 

First of all. Is this machine for leather really? The letter on the front made me think so and the big flywheel points to sewing heavy stuff. But then I notised that the feed dog doesn't lift like a four motion feed dog would do.. Is this perhaps a binder machine? (I suspect so looking into the main shaft -images) 

Second. The previous owner have put 135/5 needles in it. If I switch to 135/35 (Which I think it should have) the needle binds with the shuttle underneath. 

Tension: And as you see the machine does really poorly with leather work. This is 92 thread. The upper tension is quite high here so something is binding underneath I think. I  might need some help here. I have looked at tons of videos and read a lot of threads here at the forum. I can send more images and videos of the set up with the feed dog and shuttle etc.

Appreciate all help. Med vänlig hälsning, Erik 

[Constabulary]

54 minutes ago, Gryning said:

First of all. Is this machine for leather really?

Basically ALL sewing machines can sew leather it just depends on the leather.

54 minutes ago, Gryning said:

The letter on the front made me think so and the big flywheel points to sewing heavy stuff

As you assumed, it could have been an edge binding machine for heavy materials. Large hand wheels were also used for slowing down the sewing speed.

54 minutes ago, Gryning said:

Second. The previous owner have put 135/5 needles in it. If I switch to 135/35 (Which I think it should have) the needle binds with the shuttle underneath.

You have to raise the needle bar if you want to use a longer needle

regarding tension - most likely your bobbin thread tension is way to high (see manual for that) or you have a way too soft upper tension spring (you may need a heavier beehive spring then) or you have a permanent upper tension release for what ever reason. F.I. knee rests against knee lift lever or if you have a foot lift pedal your foot rests on the pedal....

To figure out what the numbers on the plate mean see this thread - it may help:

https://leatherworker.net/forum/topic/89283-an-introduction-to-the-pfaff-numbering-system/

Other than than check the 545 parts list there should be explanations of numbers as well. But keep in mind the plate only tells you how the machine was set up when it left the factory but not what change were done by owners or dealers afterwards (like setting is up for shorter needle).

 

Edited Tuesday at 09:17 AM by Constabulary

[fibersport]

Give it a good cleaning, oil it up and adjust it.  There is a manual for setting up a 1245 which can be used for the 545, plus there are copies of the 545 manual but honestly the 1245 manual is much better.  Your problem looks like the tension is set wrong.  The 545 is a great machine by the way although parts are sometimes hard to find and are usually pricey.

Give this post a good reading as well: 

 

Edited Tuesday at 11:23 AM by fibersport
added information

[Gryning]

2 hours ago, Constabulary said:

Basically ALL sewing machines can sew leather it just depends on the leather.

As you assumed, it could have been an edge binding machine for heavy materials. Large hand wheels were also used for slowing down the sewing speed.

You have to raise the needle bar if you want to use a longer needle

regarding tension - most likely your bobbin thread tension is way to high (see manual for that) or you have a way too soft upper tension spring (you may need a heavier beehive spring then) or you have a permanent upper tension release for what ever reason. F.I. knee rests against knee lift lever or if you have a foot lift pedal your foot rests on the pedal....

To figure out what the numbers on the plate mean see this thread - it may help:

https://leatherworker.net/forum/topic/89283-an-introduction-to-the-pfaff-numbering-system/

Other than than check the 545 parts list there should be explanations of numbers as well. But keep in mind the plate only tells you how the machine was set up when it left the factory but not what change were done by owners or dealers afterwards (like setting is up for shorter needle).

 

Thank you for the input! 

 

 Which part of the number is the sub class number? I couldnt really find my number. But I found the letters though. 

Regarding the leather sewing part I figured that the L would stand for leather. M would be the safety clutch and N doesnt correspond to any number? But I have also read that the binder machines doesnt really sew heavy thread, like the 335. This is #92 and not that heavy I think. I would like it to sew at least #135. 

Ok  I will try and raise the needle bar to accomodate a longer needle and adjust the bobbin så that the needle doesnt get crowded. 

 

 

 

[Constabulary]

545 is the class the rest of the digits is a description of a sub class

[fibersport]

I use 135 with a 22 needle on mine, works very well.  Go here and search for manuals for the 1245.  

https://www.pfaff-industrial.com/en/support/downloads/technical/documentsearch

The service and instruction manuals are what you want.  I wouldn't get too hung up on the letters and numbers of your machine, yes, nice to know but you're never sure if it was changed somewhere along its life.  

[Uwe]

Congrats on your Pfaff 545, those are really nice machines.

You missed a thread guide, which shortens the length of the thread path ever so slightly:

 

The loops on the bottom of your material are most likely due to the thread snagging at some point, which pulls more thread off the spool at the wrong time, and the machine never gets a chance to pull the knot tight, leaving loops at the bottom.

The two most likely cause for thread snags are:

1: Incorrect hook timing that cause the thread not to be cast off the hook nib at the right time. The cast-off nib is directly below the tip of the hook, at the bottom of the hook. This failure-to-cast-off causes the thread to be held in place while the thread take-up lever is moving up. This in turn may cause more thread to be pulled from the spool through the tension unit at the wrong time. If that happens, chances for a tight knot are near 0% and the odds of a loop is nearly 100%. You should be able to see this happening with a very slow, hand-turned stitch. You will also hear a distinct snapping sounds as you’re sewing.The only time thread is allowed to pulled through the tension unit is when the thread take-up lever is at the very top of its movement. To fix this problem, you very likely have to advance hook timing (make it arrive at the needle earlier), which also causes the thread to be cast off the hook nib earlier.

This video show this failure-to-cast-off problem happening on a different machine with a similar vertical axis hook. You can hear that snapping sound at the end. This particular case did not cause loops at the bottom, but I hope you see the problem :

 

Here a picture that shows that cast-off nib:

 

 

2. The bobbin case opener may not be properly adjusted and does not allow smooth passage of the thread through the gap around the bobbin case tab.If the thread gets stuck in that passage while the thread take-up lever is moving up, you have the similar result as above. Judging by the chewed-up condition of the adjustment screw on your machine, I’d say somebody was struggling to get this adjusted correctly in the past. 

This video shows the function and adjustment of the bobbin case opener on a machine with a similar hook and bobbin case opener:

 

 

 

Edited yesterday at 06:31 AM by Uwe

[Gryning]

6 hours ago, Uwe said:

Congrats on your Pfaff 545, those are really nice machines.

You missed a thread guide, which shortens the length of the thread path ever so slightly:

 

The loops on the bottom of your material are most likely due to the thread snagging at some point, which pulls more thread off the spool at the wrong time, and the machine never gets a chance to pull the knot tight, leaving loops at the bottom.

The two most likely cause for thread snags are:

1: Incorrect hook timing that cause the thread not to be cast off the hook nib at the right time. The cast-off nib is directly below the tip of the hook, at the bottom of the hook. This failure-to-cast-off causes the thread to be held in place while the thread take-up lever is moving up. This in turn may cause more thread to be pulled from the spool through the tension unit at the wrong time. If that happens, chances for a tight knot are near 0% and the odds of a loop is nearly 100%. You should be able to see this happening with a very slow, hand-turned stitch. You will also hear a distinct snapping sounds as you’re sewing.The only time thread is allowed to pulled through the tension unit is when the thread take-up lever is at the very top of its movement. To fix this problem, you very likely have to advance hook timing (make it arrive at the needle earlier), which also causes the thread to be cast off the hook nib earlier.

This video show this failure-to-cast-off problem happening on a different machine with a similar vertical axis hook. You can hear that snapping sound at the end. This particular case did not cause loops at the bottom, but I hope you see the problem :

 

Here a picture that shows that cast-off nib:

 

 

2. The bobbin case opener may not be properly adjusted and does not allow smooth passage of the thread through the gap around the bobbin case tab.If the thread gets stuck in that passage while the thread take-up lever is moving up, you have the similar result as above. Judging by the chewed-up condition of the adjustment screw on your machine, I’d say somebody was struggling to get this adjusted correctly in the past. 

This video shows the function and adjustment of the bobbin case opener on a machine with a similar hook and bobbin case opener:

 

 

 

Thank you for the input!

 

I did a calibration according to the 1245 manual. Its slightly better but I still get the loops. Especially when i turn the wheel faster.

 

I dont have any snapping sound as the one you showed Uwe. But might there be something catching in the end? I also suspect that the hook is somewhat worn..

 

 

[Gryning]

I tried to film when the thread loops over the shuttle and when I did some stitches with the hand wheel. 

https://streamable.com/lgy9r9

https://streamable.com/ufwugw

<div style="position:relative; width:100%; height:0px; padding-bottom:56.250%"><iframe allow="fullscreen" allowfullscreen height="100%" src="https://streamable.com/e/lgy9r9?" width="100%" style="border:none; width:100%; height:100%; position:absolute; left:0px; top:0px; overflow:hidden;"></iframe></div>

 

<div style="position:relative; width:100%; height:0px; padding-bottom:56.250%"><iframe allow="fullscreen" allowfullscreen height="100%" src="https://streamable.com/e/ufwugw?" width="100%" style="border:none; width:100%; height:100%; position:absolute; left:0px; top:0px; overflow:hidden;"></iframe></div>

[Uwe]

Thanks for those two videos, it’s really helpful. 

 

Your hook timing and bobbin case opener look on point, actually. There must be something else going on.The hook does not look worn to me.

One note: You HAVE to hold both thread ends when you start sewing. I can see one of the thread ends getting pulled to the underside. If thread gets pulled into works by the rotating hook you’re off to a bad start, essentially flipping a coin on whether or not you will have a bird’s nest right at the start.

From a debugging perspective, the next thing I would do is figure out when in the cycle thread gets pulled through the tension unit (off the spool.) In order to have loops on the bottom, thread must get pulled through the tension unit either:

1. More than once, including once at the wrong time during the stitch cycle

2. Just once, but too much thread gets pulled from the spool due to lack of proper upper thread tension

I’ve also seen machines where the threading looked correct, but the tension disks were permanently pushed apart due to a stuck or faulty tension release mechanism. If the tension disks are pushed apart during the stitch cycle, the machine will pull too much thread from the spool, especially at higher sewing speeds.

Another popular failure mode is when the thread wasn’t pulled between the tension disks and is simply riding around the tension disks along the outside perimeter of the disks. When threading, make sure the thread gets positively pulled between the tension disks.Your picture above shows it being correct, but it’s an easy detail to miss sometimes.

Do a few very slow hand turned stitches, and instead of filming the hook area, show us the thread take-up lever and the thread tension unit with check-spring. Tug on the thread at various points of the cycle to make sure it maintains proper tension.

I did a stitch cycle video once on my  LS-341, which, aside from demonstrating what’s supposed to happen when, is also a good diagnostic tool. 

This video shows how the tension release mechanism is supposed to work. The various Pfaff H1/2/3/4 versions have slight differences in the tension release mechanism, so yours may look a little different. In general, the tensions discs are only supposed to be pushed apart when you lift the presser feet past a certain point (to make removal of the material easier).  

 

Edited 19 hours ago by Uwe

[kgg]

1 hour ago, Gryning said:

I tried to film when the thread loops over the shuttle and when I did some stitches with the hand wheel. 

Looking at your first video it appears the tap on the bobbin case is not in the slot on the underside of the needle plate.

kgg

[Gryning]

6 hours ago, kgg said:

Looking at your first video it appears the tap on the bobbin case is not in the slot on the underside of the needle plate.

kgg

Hi, 

 

Yes that is right. The needle plate isnt there at all. I took it away so that the thread loop would be more visable. Im holding the tab with a screw driver to keep it from jamming