Part II of Threads, Needles, Bobbins and Tension. You can find Part I here.
Tension is all about balance. The balance between the upper and lower thread. Ultimately, we want our top thread and bottom thread where they intersect, to be buried in the layers of fabric.
I found this great diagram in a couple of places on the web that illustrate the two most common tension problems. Top tension too loose or tight.
Don’t you just love the little tug of war going on with the thread.
The simplistic approach to this solution is to adjust the top tension. If your machine has a manual dial, then turn right to tighten and left to loosen.
Righty Tighty, Lefty Loosey
Remember to only turn in the dial in small increments as even the smallest adjustment can have a substantial impact.
If your machine has computerised tension adjustment, same principle applies – increase or decrease tension in small increments and test.
Simple, but there is more…….
Not all tension problems can be solved by the quick flick of a dial. If you think about the pathways the upper and lower thread have to go through then anything that causes an obstacle will affect tension.
In previous post I discussed the relationship between thread and needles. If you do not have the correct size and top needle for your thread it will create resistance. Needles will dull after awhile and this can impact tension. Also, when changing the needle, make sure it correctly inserted as even a 1mm can affect tension and stitch quality.
Oil – It is very important to maintain your machine. If your machine uses oil, then use a high grade, clear sewing machine oil to add a drop to places recommended by the manufacturer. Do not over oil and never not oil. Keep your oil in a container away from heat and light. If it starts to yellow or feel gritty between your fingers, throw it out. It will damage your machine.
Remove the fluff – Cotton threads can leave a lot of lint. Invest in a good sewing machine brush and gently remove any fluff and threads from the bobbin casing, feed dogs. Practically anywhere you can get the brush in. Gently dab the brush and the fibres will pick up the lint. Avoid pushing the lint further into the machine. Never blow the lint out as the condensation on your breath can rust the parts (on non galvanised or stainless steel components). Some people use air in a can. Moisture can accumulate in these cans so spray away from the machine until only air is being pushed and then carefully and sparingly remove lint. I don’t recommend air in the can and vacuuming unless really confident.
If you have a metal bobbin casing that has a spring, gently run a very fine pin under the spring to remove caught threads. Do not damage the spring. A tiny piece of thread caught in the bobbin spring can impact on tension.
If you only do straight stitch, occasionally set the machine up with the correct foot and stitch plate for zig zag. Use the widest zig zag stitch and sew. This stops some of the older model machines from seizing.
Service – we all service our car so why not schedule you beloved machine in for a service one a year. A good service will thoroughly clean the machine out and adjust or replace any worn or wobbly components in a machine.
Re thread machine
If you have incurred a thread or needle breakage, please re-thread your machine from the start. It is amazing how often this can fix a plethora of problems. Always check the manufacturers recommendation for where the needle and foot position should be when threading.
Correct Stitch Plate
If your machine as a single hole stitch plate for straight stitch, use it. It gives a better stitch as the fabric is not sucked into the needle hole in the plate.
The way the thread winds off the spool or cone
Tension in the thread coming off the spool / cone can impact tension.Threads wind off the cone or spool either vertically or horizontally. Check when you buy a thread which way it should be placed on your machine.
Invest in a good cone holder that anchors the cone base so it does not move around too much and thread can be suspended and flow easily from the cone.
Your domestic machine will have automatic bobbin winding. Follow manufacturers instructions for threading when filling a bobbin. Check to see bobbin is filling evenly and not filling to one side or another. If the wound thread looks spongy (like Spongebob square pants), check the way you threaded the bobbin winder (taught not loose) and the bobbin is fully seated on the winding device (not raised).
Many Tensions for many fabrics and thicknesses
Tension will be different for every fabric, thickness and stitch used. Get to know these combinations and record them for future use. Most manufacturers of domestic sewing machines provide tension guidelines. Remember, they are only guidelines and you may have to do some tweeking.
P.S This is a great article on thread tension – http://www.threadsmagazine.com/item/4302/understanding-thread-tension