#9 MOST COMMON PROBLEM:
There is a great deal of confusion as to whether, where, what with, and how much to oil Bernina machines. Your owner’s manual is indispensable in this regard. It not only tells you where and how much to oil, but also which oil to use.
First, a word about the oil itself. The safest oil to use is that which came with the machine, or that which can be purchased from a dealer. Bernina oil should say “Bernina” on the tube. If you have any doubts, for instance if you have purchased a used machine and the oil is suspect, it’s probably a good idea to throw that oil out and get some more. Bernina oil is very light in viscosity, and is almost clear.
The area that is most critical to oil is between the shuttle and the shuttle race. (See owners manual) Oil this about every second time the machine is used for any length of time. Just a half drop will do.
Over-oiling just makes a mess. It’s also a good idea to oil the pin on the shuttle that the bobbin case fits over, and a little on the bobbin case latch.
Having said the above about the type of oil, I will say that I personally have used Singer brand oil (found at any Wal-mart) with good results. “Three-in-One” oil or any kind of motor or vegetable oil should NOT be used on sewing machines at all. I have seen machines virtually ruined with the wrong kind of oil.
#3 MOST COMMON PROBLEM:
BURRED OR BLUNTED SHUTTLE POINT
A “burred” or blunted shuttle pont produces a variety of symptoms. There may be occasional or irregular skipping of some of the stitches. Or, the thread may periodically shred or even break. Sometimes there will be small loops of thread on the underside of the fabric.
The “shuttle point” refers to the area on the shuttle pictured below that is directly behind the needle. It is literally sharply pointed in order to pick up the thread loop as the shuttle passes behind the needle. Because of the close tolerances of the Bernina, or due to using “knit” needles like the Singer Yellow Band, or excessive pulling on the fabric as you sew, sometimes the sharp point becomes burred, blunted or even bent. This causes the thread to hang on the shuttle rather than passing smoothly around it. The problem can sometimes be detected with the naked eye, but a surer method is to stroke the shuttle point top, bottom, and sides with your finger. Any burr or roughness will quickly be detected.
If a rough spot is detected, usually it can be smoothed, saving the considerable expense of a new shuttle. I use a Dremel tool with a rubber wheel but extreme care must be taken to not blunt the shuttle point or change the basic shape. A safer method is to use 600 grit or finer sandpaper, rubbing lightly in the same direction of the shuttle point.