The Upholstery Forum

I have a PFAFF 545 and it works great except that I can't use heavy thread in it. I normally use 92 bonded polyester as John recommends but when I try to use anything for top stitching it just doesn't pick up the bobbin thread correctly and will then jam.
Does anyone out there us heavy thread in a PFAFF 545.
Am I missing something obvious?
When you sew with decorative thread do you use the same thread in the bobbin or the standard bobbin thread.
Great machine but I would like to do some decorative stitching.
Thanks,
Ron H

I have a 545 and routinely run T135 and T210. I'd check the needle bar height and hook timing and safety clutch if you have one. There are some really good videos on youtube showing all this.

How the safety clutch is supposed to work.

Setting the timing. This is a 1245 but this part of the machine is the same as yours.

I should have started with a question, what needle and thread size have you tried?

OK, thanks for you input. If it works on your machine I figured it should work on mine. The largest needle I have is a 25, also have a 23 in my larger needle group. I put some 270 nylon thread in a #23 needle and got good results by correctly setting the thread tension. I was always looking to be able to pull my thread through after it was fully threaded. The same ease of doing this is what I was looking for using the heavier thread. Well that's not what works. I can now sew with this heavier thread correctly but must realize that it's not an easy pull through. I kept increasing the thread tension until I got a correct pattern for tension and things still work correctly.
I was always starting off with the tension way too loose which immediately caused the bunching up of the upper and lower thread on the bottom side of the vinyl.
This was 100% operator error, I just needed to be told it should work so I would go looking for the true cause of the issue.
I do also plan to check the timing.
Again thanks,

Sounds like progress. A 23 is on the small side for T270 unless you are in really thin or soft material so it makes sense you had to crank the top tension.

Pfaffs, in general, have several versions. For the 545, there should be versions H1, H2, H3 and H4. The higher the number, the heavier the work it is meant for. H3s and H4s have a safety clutch, and are meant for medium-heavy (H3) and heavy (H4) work. There is a brass tab on the front of the machine, where the version should be engraved. If it is an H2, like my 146, it probably will struggle with anything over 92 thread...
On another note, there is a "leatherworker.net" forum where one of the sub-forums is dedicated to sewing machines. I have never seen so much good technical knowledge on sewing machines as I did there. I surely learned a lot there about my machines when I started, not long ago...some very knowledgeable, and helpful, people there.
Just my 2 cents, but I'm just a rookie...

As people have already mentioned check adjustments, needle size, tension, and the machine's design capabilities. Here is a chart I made that may help.

Great reference information. I printed it out and taped it to the top of machine's table. Thanks

One question you asked was bobbin thread size, I use 92 for the bottom and it seems to work better than the larger threads, the top thread is just bigger for decoration and isn’t necessary on the bottom in my opinion.

stitchgearhead wrote: ↑Wed Feb 19, 2025 5:47 pm Pfaffs, in general, have several versions. For the 545, there should be versions H1, H2, H3 and H4. The higher the number, the heavier the work it is meant for. H3s and H4s have a safety clutch, and are meant for medium-heavy (H3) and heavy (H4) work. There is a brass tab on the front of the machine, where the version should be engraved. here If it is an H2, like my 146, it probably will struggle with anything over 92 thread...
On another note, there is a "leatherworker.net" forum where one of the sub-forums is dedicated to sewing machines. I have never seen so much good technical knowledge on sewing machines as I did there. I surely learned a lot there about my machines when I started, not long ago...some very knowledgeable, and helpful, people there.
Just my 2 cents, but I'm just a rookie...

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