Monday, December 1, 2008

Tension Snags Part 1

Over the last several posts, we have examined sewing machine tension and sewing machine repair as it relates to tensions. We have defined, explained, illustrated, and described proper sewing machine tensions. We have discussed how to adjust the bobbin tension and the upper tensions.

In this post, we will begin our discussion of tension snags.

Often the thread will snag on thread spools, rusty spots, or other surface distortions.

One of the easiest ways to fix tension snags is to rethread the machine. Double check for smooth thread flow while you rethread. Especially notice how the thread flows off the thread spool. It is quite common for the thread to snag on the edge of the spool itself. Use of a spool cap or flipping the spool up the opposite way can usually eliminate this problem. If you are using specialty thread on an oddly shaped spool, check to see if a vertical spool pin or horizontal one works best in your situation.

When you thread your sewing machine, always lift the presser foot until your reach the eye of the needle. Then drop the presser foot. This technique will go a long way in preventing problems.

During the normal sewing process, wear and tear on the sewing machine are common. When you consider that the average home sewing machine sews 650 stitches per minute, it is easy to see how little surface abrasions can occur.

As we have described before, to form a stitch upper thread is drawn through several thread guides. It is pinched between tension discs. It is tugged and pulled by springs and levers. Finally it is threaded through the eye of the needle. There are literally dozens of spots where problems can happen along this path.

And this is only the beginning. Under the needle plate, thread is wound on a bobbin. It is then drawn up through a lower tension and twisted around the upper thread to draw it up through the needle plate.

Once you begin sewing at 650 stitches per minute, dozens of sewing machine parts begin moving. They pull, tug, rotate, and twist in harmoneously coordinated action.

The result of all of this are the eventual snags that affect the quality of stitch and tensions. As the thread moves back and forth it can often score or cut into the surface of sewing machine parts.

The sewing machine repair technician needs to take time to examine all the surfaces of the sewing machine along the thread path to identify and repair problems.

In our next post, I will detail specific locations to check and how to repair most tension snags. If you want more detailed instruction on this, check out my free ebook 7 Steps To Peak Performance For Sewing Machines. You might also consider one of my extensive sewing machine repair courses.

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