Thursday, June 2, 2016

Featherweight Quilting Skill Series - Understanding Tension

Thank you for coming to my Featherweight Quilting Skill Series! There are thousands of us who love our little 221s but need or want a little more "know-how" on using them to their fullest potential. I hope my posts and videos will help you get more know-how and confidence in using your beautiful Featherweight. Enjoy the classes!

Class #7 - Understanding Tension

Class supply list:
Your fully threaded sewing machine, a small screwdriver, a few strips of fabric for test seam sewing. 

Let's get sewing!

We see the intimidating dial.

We look away from the two tiny screws on the bobbin case.
This is a bobbin case from a different machine but I liked the shot of the screws, which look the same on the 221's bobbin case. This knowledge applies to most vintage sewing machines. The 221's bobbin case is more narrow and there's a picture of it later in the post. 

We know it could eventually go awry, rear it's ugly head and will need to be tamed. I've has my battles with the underside of sewing gone wrong!

 Oh Noooo!!!!!

Tension! Maybe it's the name that causes is to freeze up, like we came face to face with a wild animal. But it's a fact of life with sewing so let's take a look at how it works and how it can be used to our advantage, not our destruction!

Basically, the upper and lower tension on the threads of the machine cause a stitch to hold the fabric together in a strong manner. Step one is to know how to run the thread through the upper and lower areas of your machine correctly. This has already been covered in Featherweight Skill Series - The Basics, Lesson 2. Review it as often as needed!

Earlier machines' upper tension dial looked like this-

Later machines had a number dial added to help with seeing the upper tension's level of tightness-
Zero is most loose, nine is most tight. 

For most of us, these units are in place and work. If you have to remove the up tension assembly for cleaning or other reasons, the Owners Manual explains how to remove and reassemble the upper unit quite clearly. The Singer manuals can be found and downloaded for free online.

The bobbin tension is a little more mysterious. Not much is said about it in the Owners Manual.  
We have a housing with two screws on its side that holds down a tension spring against the housing. 
Your thread runs from inside the case, through a channel that leads the thread between the tension spring and the housing, and then comes out so it can be caught up into the seam. You can see my thread coming out on the left side of the picture. The drag on the thread as it runs between the spring and the housing produces the bobbin tension strength. 

Try this! 
A simple test to see how tight this unit is is to set the loaded bobbin unit in your palm, grab the thread and begin to pull the unit up off of your palm. Gently bob the hand holding the thread up and down.
You'd like it to drop about 1/2" - 1" with each downward bob of your hand.

If the unit doesn't release any thread when you bob it up and down, the screw is too tight. Loosen it a little at a time until it's releasing a little thread on each gentle bob. If the thread gets released very easily or if the unit doesn't even lift off of your palm, the screw is too loose. Tighten the screw a little at a time until it releases a little thread on each gentle bob. 

Of course, this method isn't perfection and will vary from person to person, but will give you a general idea how tight your bobbin tension spring is set and will help you to know if it needs adjusting.

To make an adjustment, this is where your tiny screwdriver comes in handy. Load the bobbin into the case. Hold the unit so the string comes out from the top and the screws are up at the top. (If I had three hands, I'd be holding it in my left hand.)
The screw nearest the string is the one to adjust. Turn clockwise, or to the right, to tighten and counterclockwise, or to the left, to loosen the tension. The other screw is best left alone!

When the bobbin tension is set correctly, it needs little adjustment. The upper tension unit will take over to make the needed tension adjustments for various threads and fabrics. So having this set right is important.

As your machine is threaded correctly and you begin to sew seams, you are able to tell from the stitches which tension setting is off. The owners manual covers tension so read that section over. 

First let's look at what an evenly tensioned seam looks like. Here's the front and back of a good seam.
You cannot see either thread being pulled through to the other side of the seam. It is even! If you opened the fabric up and tried to pull it away from the seam, it should hold tight.

Here you see the bobbin thread is lying flat on the backside of the fabric and not entering the fabric at all. You can see the yellow thread coming down at each stitch point. The upper tension unit is too loose. Turn the upper tension dial clockwise to tighten the upper tension.
Sewing a seam like this works well for gathering fabric because the bobbin thread can be tugged on and the upper stitches do not lock them so the fabric gathers along the seam line. This is not the result we want all the time.

Here's another sign of top tension too loose. As I tugged on the bobbin thread it slid right out!
Actually, this seam was sewn with the pressure foot lever up. With certain attachments and during FMQ sewing, I have forgotten to set the lever down and, as you can imagine, it produces terrible stitch quality. They are unstable and not pretty. Take them out, fix your setting, and sew it again.

It won't happen as much, but the same thing can happen on the top of the fabric. If the seam shows the upper thread is pulling up the bobbin thread and is lying flat on the fabric and can be tugged on and pulled out, the bobbin setting is too loose. 
First, make sure your upper tension is at the midpoint, or set around 4. If it's too high, turn it down and sew a test seam. If it's still pilling the bobbin thread up, remove your bobbin unit, turn the screw closest to the thread a quarter turn, and try another test seam. Continue the procedure until the stitches are even.

I hope these pointers have been helpful! Please share your pics, comments, and questions.

Homework: Take your fabric strips, sew test seams. Inspect the seams to determine if your tension settings are acceptable. Make necessary adjustments as needed.

I hope you have been encouraged to use your amazing sewing machine accessories.  Please share your pics on our Facebook group page, Featherweight Skill Series, so we can see your creations! 

If you like the series, share the link with your friends, pin it to Pinterest, join my Facebook group... Most importantly, "Let's get sewing!"

See you next time!

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