Pfaff machine question..

[TonyJ 0]

i purchased a used pfaff 9020, it looks exactly like a singer 20u73 as well as other companies models...are the parts interchangeable? also when sewing thick material with e thread i have to set the top tension high to get a good stitch...is this amount of tension normal? thanks trying to learn to sew...tony

[parachutist 1]

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i purchased a used pfaff 9020, it looks exactly like a singer 20u73 as well as other companies models...are the parts interchangeable? also when sewing thick material with e thread i have to set the top tension high to get a good stitch...is this amount of tension normal? thanks trying to learn to sew...tony

Have you tried loosening the tension on the bobbin thread instead of increasing tension on the top thread? I have a straight stitch pfaff and it took me quite a bit of trial and error to realize what the correct amount of tension was for each, and that both needed adjustment.

[jumper03 0]

A good test for bobbin tension that I learned from Weird wayne called the two hemostat test. If you clip one hemostat to the loose end of the thread, the bobbin shouldn't unwind. If you clip two hemostats to the loose end, it should unwind. This gives you the right amount of bottom tension - then adjust top tension accordingly.

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[TonyJ 0]

thanks for the replies, i have played with bobbin tension, but when you pull the fabric out, it just seems to be alot of tension...i will try the hemostat test...one more question, when i sew straight it looks like a very slight zigzag? Does that make sense? the longer the stitch length the worse it looks....thanks again tony

[jumper03 0]

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thanks for the replies, i have played with bobbin tension, but when you pull the fabric out, it just seems to be alot of tension...i will try the hemostat test...one more question, when i sew straight it looks like a very slight zigzag? Does that make sense? the longer the stitch length the worse it looks....thanks again tony

Not sure about the crooked stitch, but still in reference to the fabric being hard to pull out - one other thing - make sure the mechanisms are clean and well oiled. Usually when someone asks me to look at a machine because it isn't sewing right, the first thing I do is put in a new needle, then clean the thing. You'd be surprised how many bits of thread, fabric, dirt, dust, etc drop down into the machine and they can cause the machine to mis-sew or malfunction altogether.

Jump

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[andyhughes 0]

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one more question, when i sew straight it looks like a very slight zigzag? Does that make sense? the longer the stitch length the worse it looks....thanks again tony

That is probably because you are using thick thread on thin material (e.g. type-E on 2 layers of ripstop). On a horizontal-hook machine, when the needle thread is retracted, it pulls the bobbin thread upwards (and into the the fabric - providing the tensions are correct). Now since the needle thread is doing the pulling, and oriented in the direction you are sewing, the bobbin thread will have the tendency to align itself perpendicular to that, which makes the bobbin side look a little bit skewed. Try it yourself, by hanging one length of thread off a another loop - they will rest 90 degrees out of alignment.

You may be able to play with the tension to reduce this effect, but the key thing is to make sure the lock-stitch is located in the right place (i.e. in the mid-way through the hole. The slight wonkyness is going to have an almost negligible effect on seam strength, which can't be said about getting the wrong tensions.

Solutions:
1. use thinner thread (may not be appropriate)
2. use thicker material (may not be appropriate)
3. Get yourself a vertical hook machine (drop in bobbin style)
4. do nothing - even some the best made gear has the slight wonkyness.

[TonyJ 0]

thanks for the replies, i use 2 different thread colors so i can see there the lock is, but i think i found the problem, the needles that came with the machine was size 22, i didnt know you had to use industrial needles not home needles, so i ordered many sizes. i installed an 18 and most of the funky stuff went away. guess the large needle was poking too big a hole then the thread was shifting in the hole....still learning...thanks again tony