Machine Care

Hi Everyone!

Some of you may remember back a few months ago when I wrote about the program we had at quilt guild about how a machine actually makes a stitch, and how using different fabric, thread, and needles work.  If you don't remember, you can check it out here.  Well, the gentleman who gave that presentation, Al Hunt, was at our day chapter of guild last week, and he had more important information to share.

Just to "introduce" him, Al has been repairing and servicing machines for 30 years.  He shared that he has serviced 31,000 machines of every possible type, so he knows what he is talking about.  Further, he teaches other technicians at Bernina University and also wrote the book that Bernina dealers have about servicing other makes of machines.  He is also an excellent, interesting speaker!  I'm telling you ladies, if something happens to your husband, this is the man you want to, er, "hook up" with, ha ha  (Sorry about the pun.) (If you didn't get it, the hook is the part of your sewing machine that does all the work.)

So today's topic was about cleaning and oiling your machine.   The frequency of these two tasks depends upon the frequency that you sew.  However, if it has been more than a few weeks since you cleaned (and you sew every day) then you probably should do so.  You should actually oil more frequently than you clean, maybe every few days or every 8 hours of machine use.  (I'm already in trouble!)  I personally have a routine where I wind about 6-7 bobbins and when they are empty, I clean and oil.  After hearing this talk, though, I'm going to try to oil more often.

With all the machines out there, when you get down to mechanics, there are only three types of hook mechanisms.  He gave us guidelines for each, and while it is going to make this a long post, I think it is valuable informaion.

First off, you should use a nylon brush made for cleaning machines!  Don't use a natural bristle brush like a makeup brush, as it isn't as effective at removing the debris.  (Another thing that I'm guilty of--I use a dash brush for a car.)

The first type of bobbin mechanism is called the rotary hook.  This is the style that every featherweight, long arm, and older Pfaffs (prior to about 10 years ago) are.  To clean this style you should:
1.  Remove the throat plate
2.  Remove the bobbin case
3.  Brush out all the debris from the feed dogs and case.

He said that to really get the machine clean, you should put a drop of oil on the brush.  (Just as you would use a little furniture polish on a papertowel to dust your furniture)  The oil is not just a lubricant, but also a cleaner.  The technique with the brush is not to "paint" but to jab and flip.  You can't hurt anything down in the area, so really work at it.  When the brush gets full of dirt and lint, clean it with some more drops of oil and a paper towel and keep at the cleaning until the machine is free of debris.  Also, it isn't good to use the can of air to blow the stuff out!  It has moisture in it and can cause rust.

When it is clean, the best technique for oiling is just to place a drop of oil on the tip of your small screwdriver and then touch the screwdriver to the hook where the silver basket and black gib meet. 

The next type of bobbin is the the CB (Central Bobbin).  This type is found on most Berninas and all industrial types.  It consists of the bobbin case that comes out after you release a lever.  For this you shoud:
1.  remove the throat plate
2.  unlatch the race cover so it falls open
3.  remove the bobbin case and the hook
4.  With the brush (oily) do the jab and flip method of cleaning as above.  You want to make sure that there isn't any debris left, especially in the groove where the hook moves.  That groove is called the "race" and you should consider it to be like a race track.  If any lint is in it, the effect is the same as if you have a speed bump on the racetrack. 
5.  Put everything back together.  A trick to make it easier is to tip the machine back slightly, so it all stays in place until you lock it back into place. 
6.  Using your screwdriver tip, apply a drop of oil to the race (this can be done with the cover open or closed)  Again, just the one drop is enough.

The final type of mechanism is the Drop-in bobbin and case.  This is common to some Kenmores, some Janomes, and usually the inexpensive machines.  The throatplate is opened and the bobbin is laying in the case on its side.  For this type you really need to read your manual.  Most of these bobbin cases are plastic, so they should not be oiled!!!!

To clean the drop-in, use the brush but without oil!  Really get in around the edges.  A good tip is to think of the inside of your washing machine and how socks will get stuck on the sides.  The lint will get stuck in the bobbin case the same way. 


Now that you are keeping your machine cleaned and oiled, you should just need the machine serviced about once a year.  There are exceptions, but Al said that a year is good for 99% of people.

He concluded with some tips about how to avoid some problems. 

1.  Most people don't change the needle enough.  To get some perspective on this, here is some figures.  The typical machine makes a stitch 15 times a second.  In 2 hours it will stitch 100,000 stitches.  Those 100,000 stitches would go for 230 yards--over two football fields long!  But if you read my other post that I linked above, you know that when a machine stitches, the hook grabs several inches of thread and pulls it through and then back out again.  If you stitch 100,000 stitches, you will only use 230 yards of thread, BUT the amount of thread that is pulled back and forth through the machine actually totals out to be 11.5 MILES!  All that is going back and forth through the eye of the needle, polishing the hole and possibly changing it or making a spur--and that can be why the thread fails (breaks.)  So, a good rule of thumb it to change the needle every two hours of use.  (Again I realize I'm not doing that enough.)

The next two tips are mostly for novices, but still helpful.

2.  Make sure your machine is threaded correctly.  Have you noticed that once you get experienced with threading your machine, you sort of automatically make sure that the pressure foot is lifted?  The reason for this is that when the pressure foot is up, the tension disks loosen a bit, making it easier to thread.  If you try to run the thread through with the foot down, the thread won't want to go where is should in the tension disks.  (I never knew that!)  Also, if you sew and get all those loops of thread underneath, the problem is with the top thread, not the bobbin.  Check the threading--there is probably a problem with it.

3.  Have you ever started to sew and  the machine sort of grinds a bit and then you get that lump/bird's nest of thread underneath?  This is caused by the lever not being up as high as it can go when you first start sewing.  The new, computerized machines automattically stop it in the right position, but if you don't have that feature, this is something to pay attention to.  If you start out sewing with the lever down, the machine is going to lift the lever and it will unthread your machine or will pull 2-3 inches of thread down into the hook when it isn't needed yet, and this tangles up and makes that bird's nest knot.

I hope you find this information to be valuable!  I found it to be fascinating and worthwhile to share. 

Have a great day!
JoAnne

Stitch Basics

Hi everyone!

It is Tuesday night as I'm writing this, and I just got back from quilt guild and we had the most awesome program.  Ever. 

The presentor was Al Hunt, our local Bernina technician--but hold on!  This isn't just about those machines.  He is also trained on nearly all the main brands of machines.  Not only is he a technician, but he also teaches other technicians and dealers at Bernina University.  He really knows his stuff and is a great presenter.

He shared with us exactly how a machine makes a stitch.  The only essential parts for the process are the needle, the thread, the hook (down by the bobbin) and the takeup lever.  (The takeup lever is the "arm" that goes up and down by the tension disks.  The thread is threaded through it.  On a side note, I have been hit in the forehead by it more than once while I was trying to get close enough to see something, and it really stings!)

The sewing stitch begins with the takeup lever in the highest position it can go.  As the stitch begins, the lever descends as the needle begins to lower and pierce the fabric.  As the lever descends, it plays out the thread necessary for the stitch to occur.  The needle and lever get to their lowest point in the stitch. 

(Al had a giant sewing machine needle and a thick cord that he was using as a visual aid.  I used this bodkin-thingy as a sewing machine needle.  Just pretend it looks more like one)

 

So in this photo above, my hand is acting as the fabric, and the needle has reached its lowest point in the stitch.

At that time, the needle rises just a bit to produce a loop of thread underneath the fabric.

 

Al had a term for this, I believe it was "loop lift."

  (Can you believe I didn't have a pen for notes or a camera???!!!!)

This loop is VERY important.  When it is formed, the hook grabs it, jerks out about 2-3 inches of thread, pulls it around the bobbin, and then the needle and lever rise up again, and the stitch is "set." 

The whole stitch process requires about 3-4 inches of thread to run in and out of the needle.  You don't really see that happening, but if you want to see an example, thread your machine with light thread, touch a black sharpie to the thread to make a mark at the spot where the thread comes out of your machine and heads to the needle.  Then turn the wheel by hand an observe how much that dot goes down  through the fabric and back up.  If you keep making stitches until the black dot finally appears on the fabric, you will see that you probably (depending on stitch length) made at least 20 stitches, if not more.

Why do we care about that?  With that much thread needing to move easily back and forth though the fabric, and not get hung up in the process, the size and type of needle selected becomes VERY important.  Do you get as confused as I do about needle sizes and types? 


The basic features of a needle are illustrated in the photo.  There is a groove that runs down the needle, providing a channel for the thread to travel through.  And then there is the eye, which is always somewhat elongated (taller than it is wide), and then the point.

The needle size (70, 80, 90, etc. or else 12, 14, 16, etc.) relates to the thickness of the shaft of the needle and relates also to the size of the groove.  So a 100 needle is thicker than an 80 needle, and the groove for the thread is larger.  If you are using a very fine thread, you would want the smaller groove.  If you are using a coarser, thicker thread, you will want to use a larger needle.    If you are in doubt, err on the groove being a bit larger than too small.  If it is too small, the thread won't be protected and will tend to shred.   Many of us worry that a large needle with make larger holes, and we don't want that, but really, once the quilt or fabric is manipulated, the holes will not remain (unless you are using a fusible or something.)

The point is another consideration.  There are three main types, the "sharp" which as it name suggests is very sharp and will pierce through fibers, thread, etc.  A"ballpoint" needle is more rounded, and works by pushing between the weave of the fabric, not piercing through it.  And finally, the "universal" which is in between the other two.  As you sew with the universal, it will go through most things, but also not pierce right through.  A ballpoint is usually used with knits, because a sharp will rip holes in knit and the ballpoint also becoming popular with embroidery machiness because it will go down between the threads, and not right into the other thread as a sharp may.  Have you ever been free motion quilting and the needle went right through the thread of the previous stitch?  Probably you are using a "sharp" needle and the result is that the thread snaps.  His recommendation for most sewing is to use a universal.  (The exception being knits.)  The universal needles are cheaper, too!

Finally we get to the eye of the needle.  The eye variations create types of needles like "top stitch", "metallic", etc.  In a "top stitch" needle, the eye is quite large.  It was designed so that a thicker thread could more easily pass through the eye, but when designed, the needle was used just for topstiching with a thicker thread, and not in a freemotion situtation.  The problem with using a needle with too large of an eye is that the loop formed in the "loop lift" will not be as large and pronounced, and much more difficult for the hook to catch.  The result is skipped stitches.  (This was an "ah ha!"moment for me.)  Al shared an example of how he had set up several machines for a class at Bernina University.  The instructor replaced all the needles with top stitch needles and as the class got underway, he got an urgent call that the machines were acting up.  He got there and found two other technicians, messing with all the adjustments on the machines.  Al looked at the needle, replaced them with standard needles, and the machines worked wonderfully.

I have personally attended a class where the instructor was expounding the virtues of the top stitch needle.  I was so convinced that I nearly got rid of all my others!  Obviously, there is a lot of conflicting information out there.  I have been having some problems with skipped stitches, though, so I'm going to start using the standard needles more.  (Again, they are cheaper!)

Other tips we learned:

*  Al said that if you are using a quality thread and still getting a lot of lint, maybe the eye of the needle is a little too small. 

*  He also talked about how using feed dogs differs from freemotion.  When you use feed dogs, the needle comes down, makes the stitch and then the feed dogs move the fabric.  Then the next stitch is made.  The important fact is that when the needle enters the fabric, the fabric is stationary.  When you freemotion, the fabric is not stationary.  When the needle punctures moving fabric, there can be deflection.  To help counteract that deflection, he advises using a larger needle.  So he recommends a 90 if you are really good with your technique.  If you struggle a bit, he suggests a 100.

*  The more you have constricting the needle, the larger the groove needs to be to protect the thread.  So the more layers you have of fabric/interfacing/batting/piping/other seams, etc., then the larger the needle you need.  With few exceptions, the size of the needle determines the size of the groove.

*  Changing needles:  there are a lot of "rules" out there about how long you should sew with a needle before changing (and throwing it out!!) it to a new one.  The paperwork we were given tonight suggests that you change the needle every 4-6 hours of stitching.  Al thought this could be a bit conservative.  His advice:  If you can't remember the last time you changed your neede, go ahead and do so!

I hope you find some of this information to be helpful and that it is understandable.  I experienced several "ah ha" moments and found all the information very illuminating.  I guess I didn't even know exactly how a machine makes the stitch.  Now that I know the basics, I can be more effective in  troubleshooting when I'm having a problem (in my case, it is usually skipped stitches.)

Have a great day!
JoAnne