Question about Juki MO-644D Mechanical Sewing Machine

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I can't get the tension on the right looper to work

I have adjusted it a million and one times, not to mention changed the quality of the thread. I tested it with various colors to make sure I isolate the problem, quadripled checked that I threaded it correctly. Every other looper is fine, but when I flip over the fabric and stretch it out I can see the loose thread separating the fabric--again it is definitely the right loop yet no adjustment has worked to tighten it with the many combinations with the other tensions. What can I do. I'm going crazy!

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Re: I can't get the tension on the right looper to work

Check the tension disks. Sometimes a piece of cotton breaks off in between the disks and prevent the disks to tighten properly. When you pull the thread with your left hand and adjust the tension with your right hand you should be able to feel if there is any resistance. If no resistance can be felt, it certainly is a problem with the tension disks.

Posted on Nov 16, 2007

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Brother 1034d serger skipping stitches. Stitches are loose even when adjusting the tension.

It appears that there are two issues: skipping stitches, and, loose stitches. Let's deal with them individually but first some general points to check.
1. Change both needles for completely fresh ones out of the package. Make sure that they are inserted all the way up, this is very important. The right needle should appear longer than the left one. Make sure also that you are using the correct needles for your serger.
2. Use a good quality thread with very little stretch, almost no fuzzies, and in pastel colour. Dark thread ages quicker, therefore has a shorter shelf live. A good quality sewing machine thread is also acceptable.
3. Make sure that the tension dials are clean and free of lint or other debris.
4. Re-thread the serger in this order, keeping the presser foot in the down position at all times
a) Upper looper. Ensure that the thread is securely embedded inside the tension discs. Place the thread tail under the presser foot to 11:00 o'clock and place the presser foot down again
b) Lower looper. This is the difficult one to thread but make sure that all the thread guides are properly threaded as well as the upper looper elbow. Check that the thread is lodged between the tension discs. Once the lower looper eye is threaded, place the thread in front and over the upper looper and then under the presser foot to 11:00 o'clock and place the presser foot down again.
c) Right Needle. Thread the right needle path, again ensuring that the thread is between the tension discs. Place the thread tail under the presser foot to 11:00 o'clock and lower the presser foot.
d) Left Needle. Proceed as with left needle.
e) Double check that all tension dials have their respective threads embedded between the discs by pulling firmly up on each thread above the tension dials.
f) Check that the stitch length is set to between 2.5 and 3.0, differential to normal, blade position to middle, blade is engaged, and upper looper converter not in use.
g) Set tensions to recommended setting for 4-thread overlock.
g) Make a test stitch out. How is it? Still having the same issue/s?
If yes, continue with the items listed below, otherwise have a great time serging.

Skipping Stitches:
1. Check that the looper tips are smooth. Burrs will cause problems.
2. Check that the needles match the type of fabric being sewn.

Loose Stitches:
1. Double check threading.
2. Debris caught between tension discs will also manifest itself in loose stitches. Take an 8" X 6" piece of medium weight clean and lint free cotton fabric, fold it in half length-wise and pass the fold only firmly between the tension discs from top to bottom (with the presser foot up and no thread in the tension dials).

Re-thread and test stitch. How is it now?

Sep 30, 2014 | Sewing Machines

1 Answer

What is the tension settings for normal over locking with the Elna 4de

First of all ensure that the serger is threaded correctly.

The two setting which you mention are really a 'range' for an 'average' setting.

Using 'average' fabric such as a medium weight cotton, flannel, etc.; set each of the tensions in the middle of the range and test the stitch. There may be minor adjustment required to get a perfect stitch.

Once you have stitched that first sample, here are some possible minor adjustments required:
1. Tear-drop shaped loops on the underside: Check that the thread is firmly set in the tension dial by giving the needle threads a good snug pull above the tension dials while the presser foot is down.

2. The zig-zag like thread on top should meet the ziz-zag like thread on the underside right on the fabric cut edge. If the meeting happens on top: reduce the upper looper tension slightly and increase the lower looper tension slightly ... test sew and recheck. If the meeting is on the underside: increase the upper looper tension slightly and decrease the lower looper tension slightly ... test sew and recheck.

3. If the meeting does happen along the fabric cut edge but the meeting is hanging beyond the fabric cut edge: increase the blade position (that is, move the blade to the right). If the fabric is creating a ridge or tunnel; move the blade to the left slightly.

Please let me know if this has solved your problem. Otherwise let me know what is happening with the stitch quality.

Sep 16, 2014 | Sewing Machines

1 Answer

Singer 14u34b

Assuming that your rethreading specially the upper looper and the lower looper threads tension is accurate, and still problem in getting the left/right needle to stitch then most likely looper/thread timing is out. This will need your local technician to do the adjustment.

Oct 31, 2013 | Sewing Machines

1 Answer

Adjusting tension on overlocker

overlockers and sergers are annoying in that every time you change materials and threads they must be re-tensioned.

Get a scrap piece of material. Thread your machine correctly according to the instructions in your manual. If no manual most sergers are threaded, upper looper, lower looper then needles from right to left. Make sure you thread with the presser foot UP.

You want to balance the stitches Begin by adjusting the looper dials, you want them to meet right at the cut edge. Then adjust your needles. Keep doing test seams until you have them balanced. If you are a novice... try threading with each thread point having it's own color. That will help you identify which thread is giving you fits.

Have fun.

Oct 15, 2012 | Janome MyLock 634D Mechanical Sewing...

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Stitching is too loose on the Juno Janome Serger Model 3434D

sergers the most frustrating machines. Every time you change fabrics you go through a tension adjusting phase.

First make sure you have threaded the machine in the proper order. upper looper, lower looper, then needles from right to left. Always thread any machine while the presser foot lever is in the UP position.

If you ever break a thread... you MUST pull all threads and rethread using the proper order.

Ok that's out of the way. Pull all your threads and get out several pieces of the same fabric scrap. Thread each pathway with a different color. This will help you determine which thread is giving you fits. Sew a test strip. Which thread is loose? tighten/loosen that tension. Keep doing this until you have a well balance seam. Then clip the colored threads starting with the upper looper thread, tie off to your proper color for your seam pull the thread through and up through the throat plate. proceed in this manner with lower looper, right needle, left needle. Sew a test seam.

Good luck.

Aug 08, 2012 | Janome Sewing Machines

1 Answer

I cannot get the tension right? Also, trying rolled hem with 3 needles...tension too loose.

Rolled hem would be one needle and two loopers, is this what you meant?

Make sure you move the blade to right so that you are cutting wider than the stitch being formed, you want the fabric to roll to the underside inside the stitch.

I would set top looper tension to 3 and bottom looper tension to 6 first off (needle at five, normal tension) first off and test serge with the stitch length at normal 2 or so, so you can see if the fabric is rolling under for you. There is proabably a stitch finger in the throat that you need to change too, sometimes its on the foot, (change with a screwdriver) and sometimes just a finger down on the needle plate.

Then adjust the two looper tensions making lower thread nestle up against the needle on the bottom of the stitch, and the top looper thread wrapping right over to bottom as well. Once this is happening, then turn stitch length down to close up the stitches.

It does depend on the weight of fabric too, and if you want to seam curves.

I find its best done with wooly overlock thread on top looper to "fill" in the overlocking appearance and fully cover the fabric.

I hope this is of help, if the tensions just wont behave then one of them might be faulty and machine need a service, I get mine done at least every 2 years to keep timing and tensions right.

May 26, 2011 | New Home 104D Mechanical Sewing Machine

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I have been chaging my serger to overlock for the purpose ofdoing rolled overedge. Rethreaded numerous times, have read the instructions many, many times, setting tensions, etc. I cannot get it to even...

How frustrating, I've tried to find a manual on this model so I can see how you make the change to the thread finger on the throad but couldn't see one. So, I'll go through the set up for 3 thread rolled hem on mine, it probably won't be identical but it might help.

First, remove thread from left needle and remove the left needle from the holder leaving just the right hand needle in place. Most sergers have two seperate needle screws so this can be done but as you mentioned, recheck again that the right needle is right up into the housing as high as it will go. I presume you are using a fresh smaller size needle, especially if this is on a fine or lightweight woven like organza, I'd put in a size 70. If a mid weight then size 80.

Now there should be a thread finger on the foot you change with your screwdriver. Or a little switch you flick so that the throat plate is a different shape to form the narrow seam. Your manual should have this step.

Now if you have some, put wooly overlock thread into your top looper, I cut the thread about 10 inches above the tension dial, put the new spool on, knot it to the existing thread tail, turn tension to zero and pull it through and through the looper eye.

At this point, you should have the two looper threads loose, lift the pressure foot and pull these two threads under the foot and out the back. Turn tension back to about 3 on top looper and tighten up lower looper to 5 or 6 and leave needle at 5.

Adjust blade to cut quite wide, ie wind it to the right side. Now thread the right needle and pull this thread out the back too. Lower the pressure foot, introduce a piece of fabric in under the foot, press the pedal and start trimming and chaining off.

You should have a chain stitch happening now - if not, recheck your threading, particularly the needle, sometimes the thread looks like its in the needle eye but is hooking around the looper. If you still can't get any joy, then it is possible that the timing is just slightly out and this is affecting this stitch. You could try setting up for a normal three thread seam and see if this chains okay.

If you are getting a chain happening now, then adjust down the stitch length to make it denser so it is covering the fabric and check the underside, adjusting top and bottom looper tensions so the thread is enclosing the fabric end rolling to the underside and covering any little fibres.

I hope this is of some help - however, if it still isn't giving you a chain, it could be the timing is out in which case, unfortunately service time.

May 12, 2011 | Simplicity Serge Pro SW432 Mechanical...

1 Answer


How to Thread Juki MO-134 Serger from watching lady at Lyles. Turn upper blade up. Push in first then turn up.It makes threading easier. Blue Thread upper looper first. Pull thread through tension knob. Don'tjust lay it there. (She thought that is what I must have done) Orange Thread lower looper next. Pull thread through tension knob as inthreading upper looper. Adjust lower looper so it is right nextto upper looper so that their points are almost together and directly belowsewing needles. Lower looper will be in front of upper looper (I believe). With tread from upper looper pulledback, slightly lift lower looper above upper looper and thread. I think this isright. Pull thread back with other thread. Tension is the key. Remember that. Yellow: Thread left needle first.Remember tension. Pull thread through curled wire on left side of needle arm. Green: Thread right needle. Rememberabout tension. Pull thread through curled wire on right side of needle arm. b> Note: Before sewing turn the wheel tomake sure the stitches are going together correctly.

Apr 16, 2010 | Juki MO-644D Mechanical Sewing Machine

1 Answer

My white 2000 serger is dropping the thread on the first needle when I sew with it- the loopers, both upper and lower are working correctly in conjunction with the "right upper" needle. I have changed...

Could be as simple as poor quality thread (not using MaxiLock thread), the needles not inserted properly (the left is slightly higher than the right), a missing stitch forming pin on the needle plate, the needle bar being too high or a looper timing issue.

As the needles raise, the upper looper should move to the right with the right needle tip slightly above the eye of the looper.

Jul 19, 2009 | White Sewing Superlock 2000 ATS Mechanical...

2 Answers

Janome Overlocker


Is it a three or four thread machine?

A three thread has little strength used as a seam.

On a four thread,basically, it is a tension problem. You need to ensure that the presser foot is in the up position before threading. The correct path is followed for all threads. You are using good quality thread. Reset the dials to 'normal tension' #3 or 4 .... then slowly work your way from there. The manual should offer advice on which tension to adjust to correct a particular problem.

Good luck!

Oct 08, 2007 | Singer 5160 Mechanical Sewing Machine

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