Pfaff 1245 Timing Problem

[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, 2024 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, 2024 by shoepatcher