Harris H9 stopped working

[Solarjunkie]

My trusty Harris suddenly stopped working, half way through the second leg of hemming a pair of jeans. I have found a tantalising mention online of "well know problems with vintage shuttles" but no solutions offered!
I have changed the bobbin & the thread and the needle, oiled everything, removed any visible fluff. Now I am at a loss. After a stitch or two, the thread breaks, bizarrely there are two threads attached to the piece of cloth, but the needle is unthreaded! I would not have been surprised if this had happened at halloween, as this seems like a magic trick.

At the same time, I noticed the stitch regulator, which is always set on longest stitch, is now almost on minimum, so could this be something to do with the feed dogs? Watching the shuttle from underneath, it picks up the upper thread a couple of times, then it misses the loop. but maybe this is because it is not designed to work with the baseplate vertically.

Suggestions from the more experienced very welcome.

On a footnote, I have just found out that the sewing machine my husband learnt on, his grandmother's, is an 1886 fiddleplate Singer. Pretty little thing.

[arrow]

I don't know all the finer points of long bobbin models, and this is a bit more of the same you already are on to; for trouble shooting snapping upper thread;

Check the needle, even replace it with a good quality brand for trouble shooting purposes. Make sure needle size and thread weight is reasonably matched. I once had a bad batch of needles, several packages, I don't use that brand as much anymore. The needles weren't as polished and finely finished off as the regular brands, and my best mercerised cotton thread snapped for no good reason. On the older straight stitchers; needle in the correct way!

Check the thread, does it snap unusually easily between your fingers? Is it wound around the spool pin or stuck some where?

Check for burrs in the needle plate and thread guides, sometimes thread catch and fray, any burr needs to be grinded and polished out.

Clean the tensioners; make sure there is gradual tension as you turn the nut in. Make sure tension releases and tightens properly with the presser foot lever. Clean between the tension disks, and check the spring in shuttle too.

For the feed dogs, it's very common for them to get stuck or locked up when the machine needs cleaning and oil. Take of slide plates, needle plate and clean under the feed dogs. Scrape the grooves clean with a tooth pick if they are grimy.

Detect all oil points; pay particularly attention to the parts from stitch length lever to feed dogs; oil, run the machine, turn the stitch length lever to extreme positions, keep on oiling and running the machine. Make sure everything is clean and oiled around the shuttle carrier too.

[Solarjunkie]

Thanks Arrow for that helpful reply. However, I have looked at those things! My problem is that the machine was running well and suddenly stopped, possibly sewing over a thick seam triggered the situation. I'm sure there is a little trick for this, I just don't know what it is!

[arrow]

Sew all weight Gütermann usually behaves well. Since it's jeans and you probably have gone for top stitch thread, up the needle size to #18 or #19 right away. You might need a stronger thread too, and it will match existing seams. That's the trick that usually works. Gütermann top stitch and extra strength polyester are very good for this purpose. They keep an even quality and they are strong threads. Coats and various odd brands of cotton have misbehaved on my projects; the thread can be too weak for some jobs (not meant for the purpose I guess). Check the spool for bumps and uneven spinning, it's another issue causing snapped thread.  It's always flat felled seams and the multipe folds on jeans hemming that is the the most challening part on thread, needle and machine. The jeans twill we get these days are often more light weight though.

Layers of densely woven fabric will put more pressure on thread and needle, a larger needle will give more room for the thread to pass through the fabric. A thinner needle can result in situations where you never get enough upper tension, and a larger needle can releave pressure on a thread that is a bit too light for the job. Correct size of needle will help improve all of this, and for optimal results you should have sturdy enough thread for the purpose. Polyester is stronger, if you insist on using cotton you have to choose carefully.

You can always call a medium if it get's too spooky, but I would go over a list of common check points once or twice before I did.

[arrow]

How are you doing on the feed dog movments and what type of thread are you using?

[Roger]

Have you tried a lighter fabric? If it works fine then it could be a fabric issue.
You could try putting a different coloured thread in the bobbin to the spool, that might narrow down what is happening with the weird thread issue,

Are there any sounds of catching or grating?

[arrow]

This model should stitch through regular three fold jeans hems with out much fuzz. Layers of flat felled seams are well within reach; at most you need to keep a steady speed and maybe a helping hand on the balance wheel and fabric. the feed dogs might need a bit of help over the bump. Thread breaking should't be an issue; the cause of the problem should be indentified with a bit of investigation.  These models were made to use size #21and #22 needles, mending working clothes and all kinds of stuff around the house. Jeans shouldn't be much of a challenge.