Re: Bobbin Case Jumping

Jim Stutsman
 

I don't think the issue with Schmetz needles is due to length differences. It's more likely due to a difference in the position of the eye and the scarf (dished out place behind the needle). Stitches form as the needle is rising, which causes a loop to push out behind the needle. The hook passes through the scarf of the needle, almost touching it, and grabs that loop. There are mechanical adjustments to optimize this process. The tip of the hook must arrive when the scarf is at its midpoint relative to the hook. There needs to be just enough clearance between the hook and the needle, within the scarf, to prevent contact. Janome uses Organ to manufacture their needles, and almost certainly to calibrate machines before shipping. They tend to adjust things with exceptionally tight tolerances, so minor variations in needle construction could lead to issues with one brand over another. That said, it's also true that a lot of Janome machines (ours included) do just fine with Schmetz needles. I think this could come down to individual workers in assembling the machines having different techniques. Ideally if an adjustment has a range of A to B, you would want to set things to be right in the middle of the range. But if you stop adjusting at the first point within the range, there is less tolerance. With time and use, parts of the machine may change slightly, and then fall outside the range. I think that's why we see things like sensors that suddenly start issuing warnings. If the sensor was set at the very limit of the range, it doesn't take much use to cause it to drift slightly outside. The same could be true for needles. If the machine is set to a point that works for an Organ needle, it's done, ready to ship. This may not be exactly right for a Schmetz needle.

The settings involved in the stitch process are not normally checked by service technicians. If a machine is sewing correctly, they don't go looking for things to adjust (and charge you for). Service training tells them to start every service with a new Janome/Organ needle, size 14. This, in spite of the fact that more sewing is probably done with 11 or 12 needles than 14. This leads to the inevitable needle threader problems, as well as other woes.

Which needles you use is determined mostly by what's available to you. There may be variations in the lifetime of one brand over another, particularly if they involve titanium or chrome plating, but if the world's best needle is not available where you live, it doesn't matter. If you have a brand that is working for you, and you like it, no need to change. If the brand you would like to use isn't working, ask your technician to adjust your machine using that brand, preferably a size 11 or 12 with regard to the threader. He may be reluctant to do this, though less likely if the technician is a she. A plate of brownies might help tilt the scales in your direction.

And never use those Singer needles you find in the grocery or big box "Sewing Center"! They are optimized for profit to the seller.

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