Pfaff 1245 Timing Problem

[ipswitch]

Hi all! I've got myself a Pfaff 1245-706 machine, and thanks to reading other posts on this forum I've been able to (mostly) get it cleaned up and running. When I say mostly running I mean everything seems like it's mechanically smooth, oiled and greased properly, I've spent a lot of time making sure I'm threading it properly and testing out thread and needle sizes to get the right fit. I've finished making a tote bag which mostly went fine, when I say it's running I mean that with enough fussing I've had it making nice stitches for long enough to finish a project.

The problem I'm having now (and a bit when I did my first project) is that it seems like it's incredibly easy to throw the timing off. To the point where I can't really re-attach the drip tray under the table or cover the gears that spin the hook race because I need to access and adjust them so often. I'm following the steps outlined in this video starting around 16:36. So I'm getting the needle to the lower dead point, loosening the two screws on the small gear, and adjusting so the hook meets the middle of the scarf when the needle in about 3mm up. And this works... Kind of. Like I said before, I was able to the machine working nicely long enough to finish a tote bag, but basically any little hiccup - tension slightly being off, bobbin winding being a bit too loose, etc. results in the timing being thrown off.

Sometimes if there's a big thread tangle I'll have to reset the safety clutch, but often I'll have to adjust the timing without the safety clutch needing to be reset. I can't quite figure out how this happens, as I'm re-tightening the screws on the small gear after re-timing.

One guess I have is that this is a tension issue. The thread is usually quite hard to pull through the machine when it's threaded. When I had it working properly the tension dial was set very low and that was producing good stitches, but it seems suspicious. That thread wasn't particularly heavy (it's unlabeled so I'm not sure of it's size) I was sewing with a system 190 size 130 needle which was a good size to have the thread pass through the needle easily. I'm experienced enough with sewing that I think I can match a thread and needle size pretty well. I'm currently trying to set it up to use a heavier thread, labeled as Cansew CBB138 nylon. I'm using a 160 size needle and that seems about right, but again just pulling it through the machine when it's threaded and the foot is up/tension discs loosened, it's in there quite firmly. I wonder if I should be adjusting the way I'm threading, like maybe just going through a single loop on the top finger instead of winding it around a few times like they recommend in the manual?

This is my first time working with an upholstery machine and thread this heavy, so I'm not quite sure if it's normal to adjust the threading path if tension is too high, or even if the settings should have to be so precise to avoid jams and skipped stitches. Every other machine I've used from domestics to an industrial Pfaff 563 was a lot more forgiving when it came to threading and tension, very rarely had thread breaking or skipped stitches so I'm curious to hear thoughts on what might be happening with this 1245 machine. As of right now with this heavier thread, it's not really jamming or breaking thread, but after the first few stitches the timing seems off and stitches are no longer being made properly.

I can provide pictures if that helps at all, thanks in advance!

[Northmount]

1 hour ago, ipswitch said:

I can provide pictures if that helps at all, thanks in advance!

Pictures usually help.  Make sure to resize them to 800 pixels in the longest dimension so you can post them directly to this site, this thread.

 

[ipswitch]

Alright, so here are a few images of the threading. The top tension knob here is set very low, which you might be able to see. This seemed odd to me, but it was giving me good results when sewing a few layers of 4-5 oz leather plus canvas. The bobbin tension is normal from what I can tell, it's tight enough that I can hold the bobbin + case from a length of thread without it unspooling, but if I pull gently it'll come out. Bottom stitches looked fine with this setup.

[ipswitch]

A few more images. We've got the gears on the underside, the two screws visible on that smaller gear on top are what I'm loosening to adjust the hook. There's a pic of the hook properly catching the top thread as the needle ascends. When I'm setting things up and moving parts slowly it all looks good to me. Harder to keep track of what's going on once I actually start doing some test stitches, I'll try to keep a closer eye on this for my next attempt. Also have a picture of the current needle (system 190 size 160). There's a chance it's a bit on the big side, 140 was too small. 150 is probably about right but I can't find any that size. No thread breaking or jamming so far from this needle/thread combo, but I start skipping stitches almost immediately and then the timing is screwed up. Again, it's quite hard to smoothly pull the thread through the machine, even when the tension discs are loose from the foot being up. I can do it, but it's kind of tough. I'm assuming that's the issue (best guess) but I also think this machine should be able to use this thread. I got this machine from an abandoned alterations department and it came with this thread so I assume they were using it somehow. I'll also do some testing with a lighter thread, which I could use if I have to, though I'd like to figure out what's going on here with the timing going out of whack so easily.

[kgg]

21 minutes ago, ipswitch said:

A few more images.

I had one of these for a very short period of time a couple years back but it used the 134-35 needle system. It would also slip the timing and what I found when I really cleaned everything up was those two gears as in your photo were worn and the larger gear needed to be moved forward to get better contact with the other gear. I just slacked the shaft off at the safety clutch and moved it forwarded.

kgg

[ipswitch]

Brilliant! Thanks kgg, I hadn't considered that. This thing got slammed around a lot when I was moving it so this is a good idea to check. Seems like moving that big gear is pretty simple, I'll give it a go and report back.

[nejcek74]

maybe follow the complete timing setup as is written here:

https://www.supsew.com/download/Pfaff/Pfaff 245, 1245%3B 246, 1246 Service Manual.pdf

setting the right distance of those two gears is also a part of the set-up (5.8 somehow vaguely written, but I think one can understand what they meant: not to tight, not too much play, I was spending some time with that till I was satisfied). After I bough the machine I learned how to to do the whole set-up and after I never had problems.

[ipswitch]

Thanks nejcek74! I'd gone through a few versions of the 1245 owners manual, I actually didn't realize there was a service manual like this available - it makes sense, I'm kind of new to doing this level of work so I guess I thought the pro's just knew magically how to do it? I'm going through it carefully now, going to make some adjustments and test again.

[ipswitch]

Wheewwwww ok this keeps getting more interesting. Good news / bad news I guess. I went through the service manual and everything seemed to be in the right place and doing what it was supposed to be doing except for the placement of those gears. I moved the hook back by about 1mm since this bigger needle I'm using is actually hitting the hook, just barely but enough that it might have been an issue. Also moved the collar on the shaft next to the large gear so that it was up against the gear as outlined in the manual - it previously wasn't so this adjustment might help with skipped stitches I suppose.

Here's the fun part - figuring I'd have better luck with those couple adjustments I put everything back together and now the feed dogs aren't moving!? I have the presser foot and walking toe moving up and down, no forward/back movement and no movement at all in the feed dogs underneath. I can't figure out how this could have happened, I didn't adjust anything except for the 1mm hook assembly move and the collar next to that big gear, neither of those parts seem to have anything to do with the feed dog movement. I must have done something. Going to slowly go through the manual again and see what I can figure out about these parts, I previously left them alone because they were moving properly. If anyone has a brilliant idea of what this might be, I'd love to hear it, otherwise I'll keep working my way through this manual.

[ipswitch]

Alright good news, I'm an idiot! While I was following the service manual it had me set the stitch length to 0 at one point... I knew it was going to be something like that. I forgot it was set like that and just thought I'd somehow borked the feed dogs or something. Thanks for joining me on this journey lol. Still have to put some things together and do some more tests.

[ipswitch]

Still at it unfortunately - I've already gotten some really good advice, which I've followed, but I still haven't fixed my issue. I made sure the gears were placed properly, they're not too worn down and I don't think they're responsible for skipped stitches. I went through the service manual and everything looks ok as far as I can tell, one thing that caught my eye was the thread check spring - I set it properly for the material I'm using, I've just noticed it clicking and jumping around a bit.

I actually recorded a couple videos of the machine running in hopes someone could take a look and spot something I haven't seen. Watching them again I can see the check spring clicking and moving in a weird way, which is maybe it's reaction to something else happening, or maybe that's where the problem originates from?

I've got two videos of the machine / problem here, the first one HERE showing the bobbin and hook, the second one HERE showing the thread path and check spring. Something is snagging and causing skipped stitches and frayed thread. I can pull the thread through the machine easy enough and without damaging the thread, so I don't think I have any burs or sharp bits along the way. The fraying only happens when I'm actually making stitches. Thanks again if anyone has time to take a look, I really appreciate it!

[ipswitch]

OK, I think this should be the end of it - I removed the plate that the tension discs are on, cleaned it out (it was a bit dusty back there) and adjusted the screw that controls the amount of space between the tension discs when they're open. I loosened it, which should allow thicker thread to move through a bit easier. I think whoever was using this machine last was using much lighter thread than I was. I also set the upper tension incredibly low, to the point where the nut that tightens the upper tension disc was barely on. I had the tension set loose before, this is about as loose as it'll possibly go. Weirdly, that's fixed my problem regarding fraying thread and skipped stitches. And this is after I went back to a medium weight thread, it's not even the heavier stuff I was trying to use before. It makes me wonder if there's something weird about this set up, or wrong with the machine, because if I ever need to set the tension looser than it is now I can't. Anyway, it's enough to get me back to work. If anyone has any insights about this (maybe that's just how these machines are?) feel free to chime in. Hopefully this will save some trouble shooting time for anyone googling this issue in the future!

[kgg]

10 hours ago, ipswitch said:

I've got two videos of the machine / problem here, the first one HERE showing the bobbin and hook, the second one HERE showing the thread path and check spring.

This appears to be the same PFAFF 1245 machine that I had for a very short period of time.

5 hours ago, ipswitch said:

And this is after I went back to a medium weight thread, it's not even the heavier stuff I was trying to use before.

The threading appears to be correct up to the last thread guide just before the needle. In your second video I noticed the thread guide just before the needle appears to be different then the one I had on my machine and seems to be further to the right side of the shaft rather then being more too the center. The manual I have in figure 1-01, figure 7-04 and figure 9-01 shows the guide being centered.

According to the manual " Use only system 134-35 needles " and it could take size 110 to 140 ( #18 to 22 ) needles which means it could handle V69 to V92 in thicker stuff and V69 to V138 in thinner stuff.

My machine would not work with V138 except in thinner fabric.

The thread fraying at the needle maybe being cause by a burr at the needle plate/feed/ etc. or the hole in the needle plate andfeed dog may not be large enough for the needle system you are using.

I have included the manual I used and a photo of my machine, nameplate and needle area. Note: In the machine photo I miss threaded the small round tension guide just before the main tensioner.

kgg

 

pfaff_1245_1246-manual-EN.PDF

Edited August 23 by kgg

[ipswitch]

Thanks for the insights! This machine came with a manual and a supply of needles, the biggest size being 140. I hadn't noticed that the manual mentions 140 is the limit, though looking again it seems like that's the case. Interesting because this machine also came with some thread that's heavier than what you could use with a 140 needle. I mention in an earlier post I found some 160 size needles, which seem like they fit without striking anything, though putting thread that heavy through the machine might have been too much, there was just a lot of tension even when the discs were slacked, so maybe I abandon the dream of using that thread for now.

I'll have a closer look for burs where you mention, I don't think it's the cause of fraying since the last few adjustments I did seemed to have stopped the problem for now. I think you did spot something I need to fix though, that last guide for the thread before it gets to the needle doesn't look like the guides I'm seeing on other machines. I think it's improvised and may be a bit loose, that should be a cheap part to replace so I'll do that.

Thanks again for the help! The machine is in better shape now, should be able to continue work with it.

[shoepatcher]

Go to a #160 needle.  I use them with #138 all the time.  

glenn

Edited August 25 by shoepatcher