Have you noticed when you’re changing from one project to another the thread all of a sudden starts to loop, get tangled in the bobbin area or other crazy things? The fact is that as you change projects and start sewing on different weight materials, you should test the stitching on a piece of scrap material of the same weight you’re changing to, before beginning the actual project.
As an example, if you’re changing from a denim type material to a silky type material, you would definitely want to make sure the tension is correct and the stitching looks right before you start to sew on the new project.
First, be sure you KNOW where the upper tension is located on your sewing machine (check your manual). It can be on the front of the machine, the left side (or end) of the machine, or it could be at the top of the machine, depending on the make and manufacturer of your machine.
Before attempting to adjust the upper tension, you will need to understand how the upper and lower thread works together to form a stitch and do a test to see if the tension is actually “off” (see Figure 7A, 7B and 7C).
The above diagrams show you how the tension SHOULD be and how they would look if there is a problem.
To determine whether the upper tension is too tight or too lose for the fabric you want to use, try the following test. Take a small scrap of the fabric, fold it, and stitch a line on the bias of the fabric, using different colors of thread in the bobbin and on top. Grasp the bias line of stitching between the thumb and index finger. Space the hands about 3 inches apart and pull with an even, quick force until one thread breaks, as in the following diagram.
If the broken thread is the color of the thread in the needle, it means that the upper tension is too tight. If the broken thread is the color of the bobbin thread, the upper tension is too loose. If both threads break together and take more force to break it, then the tensions are balanced.
The above sewing machine repair tip is brought to you by Reuben O. Doyle, author of Sewing Machine Repair for the Home Sewer — as well as author of the Complete Guide To Treadle Sewing Machines, Serger Repair for the Home Sewer and Sewing Machine Repair as a Home Business. In addition to checking out the Sewing Machine Repair book at SewMachineRepair.com, you can also check it out at Amazon.