Pfaff 335 w/ 135 Thread Having Tension Issues

[drawingonblank]

Hi Folks!

I've been trying for about 2 straight days now to balance out the tension between the top and bottom threads of my Pfaff 335 machine (pictured below). I've tried EVERYTHING to get these stitches to come out evenly but keep getting the results shown in the sample stitching below. The closest I can get to even is to tighten the top tension nearly the entire way and loosen the bobbin thread tension to nearly nothing. That seems off to me. I've tried winding the bobbin at different tensions, checked my needle (135x17 SD1 #22) and still... I get this. I just don't get it. When I do get very close, the top spool thread also tends to fray. 

What am I doing wrong? Please help!

[Constabulary]

The 335 usually is a binding machine and not necessarily set up for heavier leather work. Just from looking at the picture I´d say you have to reduce the bottom thread tension and / or try a heavier tension spring in the top tension unit and / or try a needle 1 size bigger. Or try a thinner bottom thread. Are you using a leather needle or round point needle? I guess you bought the from Atlas Levy, right? They should be able to supply a heavier top spring.

Just some suggestions...

[Hockeymender]

I would suggest trying a larger needle. 

[brmax]

I think some things do promote good patterns for the many, that said I like to use one pair of holes in the thread post.

To add I don't always use that pattern in fact I consider the big thread and use it to take a twist out, or attempt that.

With all this hot air in my reply, I don't feel its a hard rule to use a pair of them holes in the thread guide post so just one is fine as a guide In my opinion.

It also seems to me different thread types can be way different in the mix and so the bobbin can be set next to nota and maybe 1oz for a test.

 

good day

Floyd

[shoepatcher]

One thing I would look at is the size of the needle hole in the feed dog.  If you are going to use #138 thread, that hole has to be enlarged.  What happens is as the needle is going down thru the feed dog, the size of the how in the feed dog forces the thread from the left side of the need to the front of the needle and that means the bottom tension comes out to tight.  I would look at the tension spring on the shuttle hook and make sure it is tightening down properly.  No dirt or lint under it and not grooved in the back.  Make sure take up spring is set correctly and traveling correctly.   These machines will sew #138 as long as they are set up properly.  One other thing might be the spacing on the finger where the bobbin case moves back and forth.  horizontal hooks do not have a proper bobbin case opening to adjust like on a vertical hook machine.

glenn

[brmax]

The top photo stitch line 2 from right where thread broke I suppose and where it shows frayed looks a bit tight, and actually close but maybe overworking to pull up bottom.

Especially when flipped over and see the corresponding stitch line 2 from right (around the 2:00 position) and though hard to see it looks as though the knot is centered or buried anyway and I'm not seeing it on that specific part of the line.

Some reason I cannot see much of a hole in the bottom and sometimes that's the way it is, not as purdy, but the hole in the top to my eyes is big enough. So maybe a needle type as a change may help the bottom pull up easier if ya can find one, or try a bigger one as mentioned at first.

Floyd

Edited December 20, 2016 by brmax

[dikman]

What size thread? Looks like #138?

[Darren Brosowski]

If red is the top thread then you are going the wrong way as there is no top tension

 

[RockyAussie]

First step I would try is use the next size down thread in your bobbin. This will make it easier for the top tension to pull it up into place and look better.

2. I think the the thread looks a bit twisty and I suspect hard firm so maybe think of a thread change.

3. If the leather is stiff and hard consider can you use a softer lining.

Brian

[drawingonblank]

Gah, thank you all for so many helpful responses!

Here's what I ended up doing and it more or less worked but my machine does NOT seem to like the combo of leather with the #138 bonded nylon thread I'm using. I think it's in the upper range of what my machine is capable of and I'm considering getting a Cobra Class 4 after this experience. Anyway, I digress:

1) First, I tried what Constabulary suggested and got a stronger tension spring from Atlas Levy. That definitely helped. 

2) Then I switched out the size 22 needle for size 23 and I think that did it. 

I still had to very carefully create my locked stitches from the start point and the end points but I didn't have any trouble with it fraying or bunching as long as I kept track of the tension. Around corners it still seems to be a little loose on one or two of the threads but it's still LEAPS better than the last post.

Any advice on how to clean these up a bit more would be great but man it's so much better already. (Under side of stitch is pictured. Top is perfect.)

 

 

[dikman]

I just read the title more carefully - 135 thread (doh! me dummy!). I had problems with my old 335 when I first tried 138 thread (it worked fine with 69), it was dropping stitches and causing fraying due to the hook snagging the twists in the thread. I had to tweak the position of the hook saddle (can't think what it's called at the moment, the bit holding the shuttle assembly). I found it was pretty fussy adjusting it so that the hook would catch the thread correctly. Also the thread tension take-up spring (the one mounted on the tension discs) needed tweaking a bit.

The photo also suggests to me that a bigger needle may help.

[RockyAussie]

I still think the thread looks wrong but is it possible to post a close up pic of the feet and in particular the dog foot. I am curious about the relief slot for the bobbin thread to follow and position in. I did a major improvement once by hollowing out more for the thicker thread and angling a bit at the same time.Just a thought if the next size down thread in bobbin is out of the question. Also is it a Tri or LR needle? If it is a round point you have no hope.

[drawingonblank]

1 hour ago, RockyAussie said:

I still think the thread looks wrong but is it possible to post a close up pic of the feet and in particular the dog foot. I am curious about the relief slot for the bobbin thread to follow and position in. I did a major improvement once by hollowing out more for the thicker thread and angling a bit at the same time.Just a thought if the next size down thread in bobbin is out of the question. Also is it a Tri or LR needle? If it is a round point you have no hope.

 

[RockyAussie]

OK , I have not seen before the curly thread thing on the bobbin case so I dug in around the back of a 40' shipping container and took some somewhat dark pics on one I haven't used in a good while.  By the dog foot I mean the foot with the groove in it as I have pictured in the 2nd pic. Just also check your back foot is coming down level with the base as you may not be getting the pressure down right as the needle is lifting out.Your picture looks like it is angled high at the front.

[dikman]

That little curly piggy-tail is certainly....different. I'm curious as to its function.

[SARK9]

My original Singer 20U33 bobbin cases have that as well....

 

-DC

 

[dikman]

Son-of-a-gun, so there isn't anything new under the Sun . So, what does it do?

Edited December 21, 2016 by dikman

[Northmount]

That guide on the bobbin case is for doing zig-zag stitching.  My Singer 20U instructions indicate it can be bypassed for straight stitching.

Tom

Edit:  On the Singer 20U, the face of the bobbin case is parallel with the arm, not 90 degrees like the Pfaff, so this comment isn't really relevant to the Pfaff.  More likely to aid timing when changing stitch lengths and the motion of the walking foot.

[spenzher]

Have you tried using different thread for the top thread? I had some thread once that would twist right before it got picked up by the hook and would make an extra big twisty knot. This made the knot impossible to be pulled up onto the needle hole, resulting in loose stitches and was indicating loose top tension. I wonder because I see some stitches look crooked like mine were. I switched to a different spool and the problem went away. 

I'd try using a different spool (still sticking with 138) and see what happens. 

Edited December 22, 2016 by spenzher