Mechanic Hands

I enjoy being a sewing machine mechanic, 

but it sure is hard on my hands.

I put a screw driver through my pinky fingernail, 

and smashed my thumbnail.

Some days they just don't get clean, 

no matter how many times I wash them.

It's a good thing I love my job!

The Wrong Oil

I'm working on an old White sewing machine.  DH got it for the foot control, but I want to try to fix it up to sell.  The problem seems to be that the previous owner used the wrong kind of oil.  

It took DH's muscles to un-screw the center knob.  And my sons helped me get the handwheel off.  After trying to pull it off, we tried to pry it off with a screw driver, which didn't work.  Then we finally positioned a screw driver on the inside metal casing, and smacked it with a hammer.  That worked!

The "Before" picture is fuzzy, but you can see the red-ish, sticky, old oil.  That is what old oil or the wrong kind of oil looks like, and it feels tacky to the touch.  It's just like glue.

To remove the old, gummy oil, I put some WD-40 on it and scrubbed it with an old toothbrush.  It didn't get all of it off, so I used a very fine sandpaper to get the rest off.  The inside of the casing on the handwheel also needed scrubbing as did the center knob and the position ring.

So, what kind of oil should you use?  Only "sewing machine oil."  That doesn't include 3-in-1 oil, engine oil, olive oil, or FAX machine oil.  And, as you can see, it doesn't include WD-40.  We only use WD-40 to REMOVE the old oil.

Sewing Machine Tensions

Lets talk about tensions.  When a machine comes into the shop, no matter what the problem is, the customer will usually say, "it's the tension."  If the timing is off, "it's the tension."  If there's a burr on the hook, "it's the tension."  If the needle is in backwards, "it's the tension."  You get the idea.

I'll do a run through on how we balance the tensions at the shop.

Before we can work with tensions, we clean and oil throughout the whole machine.  It's especially important to clean and oil your bobbin area before working with the tensions.  That's something you should be comfortable doing yourself.

When you thread your machine, the presser foot has to be in the up position, to open the upper tension disks.  If the presser foot is down, the tension disks are closed tight, and the thread can't get into them.  When that happens, your fabric will have loops on the bottom, like this...

You can click on the pictures to make them bigger.

Next, make sure there's no lint in the upper tension disks or inside the bobbin case.  You can sweep the lint out with your lint brush.

Then set your upper tension dial on "normal."  If you don't have a "normal" setting marked on the dial, set it at 3.

Correctly thread your machine, top and bobbin.  Put a light colored thread in the bobbin and a medium to dark colored thread in the top.

Set your machine to do a medium zig-zag (unless your machine is just a straight-stitch machine).  On most machines it's 3 on the width and 2 on the length.

Sew on a light colored, good quality, cotton fabric for about 6." 

If the bobbin thread is pulling to the top, tighten the bobbin case tension by turning the little screw to the right.  Remember, "righty tighty, lefty loosey."  Here's some pictures of  bobbin case tension screws...

If the top thread is pulling to the bottom, that's what you want it to do.  But, you only want the top thread to be a "tick" on the back.  If it's really pulling to the back, loosen the bobbin case tension by turning the little screw to the left.

After working with the bobbin case tension, if you're still not sewing well, try adjusting the top tension.  It works just opposite of the bobbin case tension.  If the thread is still pulling to the top, loosen the upper tension.  If the thread is still pulling to the bottom, tighten the upper tension.


Here's my nearly perfect sew-off sample.

If you're still not sewing well, it may not be the tensions, and you may need to take your machine to the shop.

Quilt Guild Presentation

This past week, I was asked to come to 2 quilt guilds to give a sewing machine maintenance class.  One guild wanted a hands-on class where they opened their machines and did what maintenance they could on them.  And I took my camera, but forgot to take pictures.  Dang!  The other guild just wanted a lecture/demo.  There were 7 students in the hands-on class, and about 30 at the lecture/demo.  It was great!  I love teaching these classes!

One question that was asked at both classes was, "what gets done when we bring our machine in for a service?"  So, I've made a list. 

When you bring your machine in for a full service, here are some things that get done:

1.  Clean and oil throughout, which can get very deep.  We remove some, or all of the outside of the machine, and use an air  compressor to blow out the lint.  We oil where metal rubs on metal, and put grease on certain gears and tracers.

2.  Service the motor.  Older machines have carbon motor brushes that wear out and may need to be replaced.  We oil the bearings at each end.  In addition, we clean the motor’s commutator (or armature) when it’s accessible.  Then blow the carbon and lint out of the motor when it is open.

3.  Check the belts.  Belts need to be replaced when they start to shred, get deep cuts in them, or get saturated with oil. 
 
4.  Check the electrical components.  Foot controls and cords on older machines may be a fire hazard.  On newer machines, circuit boards and stepping motors need to be checked.  We also make sure the lights are working properly.
 
5.  Check for mechanisms that have been gummed-up with old oil.  When necessary, we use a solvent to remove the old oil, then re-oil.
 
6.  Replace or repair any broken parts.

7.  Polish the burrs and scratches off of the hook and needle plate, if needed.

8.  Replace the needle.

9.  Check and set the timing.  We make sure the needle, hook and feed dogs are working together to make a good stitch.  Never try to adjust the timing yourself!  There are too many variables, and you may just scramble your machine.

10.  Balance the tensions and do a sew-off sample.

11.  Clean the outside of the machine.

What To Bring With Your Machine When It Needs a Service:

1.  Foot control and power cord (these need to be checked, too)

2.  Standard presser foot.  This is the foot that can sew all of the stitches on your machine, and has a nice flat bottom.  We need this foot to do a good sew-off sample.

3.  Bobbin case (so we can balance the tensions)

4.  The right bobbin

5.  Thread (if a particular thread is giving you trouble)

6.  Embroidery module and hoop, if it's an embroidery machine

7.  Please write what problems you are having on the service order, and if you’d like to include a full service.

What NOT to bring (because we may loose them):

1.  Accessory case and accessories
 
2.  Carry case, bag, box or crate
 
3.  Walking foot or other specialty feet

4.  Thread (unless the thread is giving you trouble)

5.  Snap-on sew table

If you are still having problems after the service, please bring your machine back right away, so we can sit down with you, and figure it out.

Bobbin Winder Clutch

Sometimes, if you're working with an older sewing machine, your bobbin winder won't disengage, and the needle will go up and down while you're trying to wind a bobbin.  This can be caused by 2 things.  #1)  you've got some old oil on the shaft inside that needs to be removed.  Or #2)  the ring under the bobbin winder clutch is in the wrong position.  Here's how to fix it...

Here's a picture of a bobbin winder clutch.  It's on the handwheel of this old Kenmore.  First, loosen the small screw on the center knob.  You don't have to take it all the way out, just loosen it.  Then twist the center knob to the left (righty-tighty, lefty-loosey) until it comes off.  This is a picture of what you'll see under the knob.  Can you see the metal ring that's sitting on the center shaft?  Remove it.

You may need to take the top lid and/or the side panel off to allow the handwheel to move in and out.  If you're not sure you can get the belt back on correctly, you don't need to take the belt off, just loosen the outer panels so you can move the handwheel on it's shaft, like this...

Can you see how the center shaft has moved back inside, as I push the handwheel out?  Use some "solvent" (WD-40) to remove the old, gummy oil on the shaft.  Squirt it inside the hole and work the handwheel around until the gum is dissolved.  Then wipe out as much of the solvent as you can.  If you have a can of air, you can blow it out -- we use an air compressor at the shop.  Also use the solvent to wipe the old oil off of the metal ring and center knob.


Put 2 drops of oil on the shaft and put the machine back together.
  
The metal ring under the knob will have 2 or 3 raised nubs on the inside.

The raised side of the nubs should be facing outward.  Put the ring in place, with the nubs in the slots on the shaft.  (Take a closer look at the second picture above.)  Then screw the center knob back on and tighten the little screw.  You should be able to release and re-tighten the center knob.

Run the machine and see if it's doing what it's supposed to do.

If the machine isn't working well with the ring in its current position, turn it counter-clock-wise one position.  Screw the center knob back on and tighten the little screw.

That should take care of it!

Tensioners for Bobbin Winding

Here are some pictures of "tensioners."  They're a small post with a springy part.  When you wind a bobbin, you need to wrap the thread all the way around the tensioner.  On most machines, it makes a "figure 8" as it wraps around.  If the thread doesn't go into the tensioner properly, you'll get a sloppy, loose bobbin.

House Call

My neighbor just called me to come check her sewing machine.  She has a Bernina 801.  Great little machine!  Her complaint was that it wasn't feeding the fabric through.  When I got there, here's a list of what I found.
1.  The feed dog drop switch was set for "darning," but the feed dog height was also low.  So we moved the switch to "sew," and raised her feed dog height.
2.  The needle was in backwards.  We put the needle back in the right way, with the flat side to the back.
3.  The bobbin tension was way too tight, and the upper tension was set loose.  So we put the upper tension on its "normal" setting, and loosened the bobbin tension.  Then I did a sew off sample, and balanced the tensions by adjusting the bobbin tension.
4.  When I asked for a different color thread for the top thread, she handed me some "hand quilting" thread.  I told her to NEVER use "hand quilting" thread on a sewing machine.  You CANNOT get a good stitch with "hand quilting" thread.  And you may get a burr when it tangles and pulls the needle into the hook.