Tech Sunday - Bobbin Cases

Most of us don't think about our bobbin cases very often.  Usually we only pay attention to them when we are setting our tension.  They are an essential part of our machines and we all should pay a little more attention to them.  When we don't they have a tendency to make us pay with things like tension that we can just not get to balance.  Frustration until you want to throw something or scream.  That little metal case can cause a grown girl to cry... literally.    I don't know about you, but every once and a while I drop a bobbin case.  I try not to, but it happens.  Even dropping it on my carpeted floor can knock that case out of round.  It is important to really look at your case if you drop it.  If it is out of round replace it.  It is just not worth the headache of trying to balance tension with a bobbin case that is not round.  Trust me, I have tried.  I have even trying to reround the case and that has not worked out very well for me.  Bobbin cases are relatively cheap.  Always have a spare or two.

There is a little finger on the outside of the case that the thread goes through.  It is a place that loves to collect lint.  I use a very thin pin and drag it under the finger to where from the screw down to the area the thread comes through.  I do this a couple times a month and almost always get lint out from under the finger.  If you can't get your bobbin tension to work out right.  Check to see if there is lint under the bobbin finger.  

Another place that can cause a problem is the check spring.  The spring is the disk that is inside the bobbin.  It is designed to hold the bobbin away from the back of the case and to prevent the bobbin from spinning backwards when you change directions or stop quilting.  When you put the bobbin into the cause you should be able to feel that the bobbin springs back towards you slightly.  The bobbins should look like is slightly too tall for the case.  If it looks like the bobbin is indented into the case, take it out and bend the 2 little arms on the check spring so that it holds the bobbin a little farther out of the case.  Eventually you will need to replace the spring. 

There are magnetic bobbins that are designed to work without the check spring installed.  I actually have 3 bobbin cases in use at anytime.  One with no check spring for MagnaGlide magnetic core bobbins, one that I use with prewound Superbobs and one for bobbins that I wind myself.   I also keep a couple brand new spare bobbin cases on hand.