Pffaf industrial machine trouble
 

My son is trying to install zippers in a covering for the wing of an airplane. He is using the company’s Pfaff industrial sewing machine. He is having trouble with the machine skipping stitches and called me for help. I suggested it might be a tension problem, the machine not threaded correctly or the wrong size needle. He sent me a picture of the needle pack he is using. I have never seen this make but is this a size 10 needle like it seems to be? He is using upholstery thread and if this is a size 10 needle, I think it is too small

Here is a picture of the needle package ( hopefully)

I think you are right in that it could be the needle is too small. A size 10 needle is the equivalent to a 70 needle which would be used for cotton and thinner thread than upholstery thread. I don't know what material he is stitching on nor the size of the upholstery thread he is using. The picture of the needle package is a German made needle. They make many different sizes and types of needles The ones I use are round shank and used in my long arm.

I believe that the size is NM 150 which is a 22.5. So that is probably a good size for heavier thread. The LR needle has a slanted point and is to be used to sew decorative seams on soft to medium hard leather. I found this information on https://www.thethreadexchange.com/mi...ode=NDL-717282 and https://www.thethreadexchange.com/mi...ode=NDL-134-35

Janey - Neat people never make the exciting discoveries I do.
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ETA: The NM is a metric number and a description of needles for industrial machines can be found at https://www.servicethread.com/blog/i...d-needle-sizes

In addition to what you have already suggested, there could be some other things that might be checked. I didn't realize there were so many reasons for skipped stitches as indicated at https://sewingfeed.com/why-is-my-sew...ping-stitches/

I don't know what the exact problem was other than question about same needle at https://www.quiltingboard.com/vintag...p-t319442.html but it sure wouldn't hurt to clean and oil.
Janey - Neat people never make the exciting discoveries I do.
Not affiliated with off-site link(s)

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Thank you for your responses. I have copied the responses with links to send to my son. If all else fails, they might need to have a sewing machine repairman come to look at it. I use a very good repairman and will recommend him if need be.

I have Pffaf quilter machine and making sure it is threaded correctly is 1st on list.. tension and needles are correct for the thread size and being clean will also help in the quest ..some times a tiny bit of fuzz or thread will cause the problem. hope you are successful in getting the machine to sew correctly. They are wonderful machines but sometimes troubleshooting is a challenge