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Pfaff 1151 bobbin tension

I'm having a problem with the bobbin tension. The stitch looks fine on the front and on the back it's loopy. I've tried tightening the top tension which gets a bit better. I've loosened the bobbin tension and tightened the bobbin tension. The machine was working fine until I ran out of bobbin thread and put in a new bobbin. I've tried putting the bobbin in as it shows in the manual. I've had this machine for fifteen years and know it inside and out. This one is throwing me for a loop!

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5 Suggested Answers

  • 46 Answers

SOURCE: Thread loosens underneath intermittently. Stitches not consistent.

take it to a serviceman.

Posted on Oct 24, 2008

  • 1388 Answers

SOURCE: thread loosens in bobbin case while sewing

If you are using a standard top tension of 4 or 5 and this problem has developed over time, the most likely cause is lint deposited between the tension disks....... if the top tension is loose, or in the tension spring of the bobbin case if the bottom tension is having troubles. In either case you need to remove the lint......
Raise the presser foot and with a length of scrap fabric, use an action like flossing your teeth to get between the top tension extreme cases a probe (old needle) may be used very gently to remove thread and lint, but be VERY careful not to scratch the polished surfaces. 
I have also written a tutorial on tension balance which may be of further assistance, particularly for bobbin tension issues: 

Please TRY the solution BEFORE giving your considered rating.

Ensure that all is clean and free of lint and jams, this is the most likely for tension troubleshooting .......

This solution is for tension problems...if you cannot form any sort of stitch, the issue is quite different, so please let me know if you need a different problem solved.....

It is quite long, but just work through each section in order.
The "knotting up" can reveal a lot. If you have loose threads on one side or the other, the tension on the opposite side will be the culprit.

Ensure sharp new needle, 
Thread guides and Bobbin are Clean & Clear of lint
Set Top Tesion to 4 ....then....
Balance Bobbin to suit.

If the looping threads are on the underside as you sew, it is the top tension. Top tension ought to be between 4 & 6 (this variation to allow for the different weights of fabric in your 

If you are using a needle that has seen quite a deal of work, or you suspect it may be blunt, change it for a new one !

Make sure that when you thread the machine the presser foot is up so the thread goes between the discs and not to one side, top tension between 4 and 6, and that you have threaded through all the guides, including the last one, usually on the needle arm, just above the needle clamp.

It may be there is lint trapped between the discs, this will keep them slightly apart and reduce the actual tension, sometimes dramatically.

If tensions appear correct, and the thread is definitely in the channel between the discs, but still too loose and looping, try raising presser foot and remove your thread.

Now, with a 2" (50mm) wide strip piece of fabric 8 - 10" (20 - 25cm) moistened with methylated or denatured spirit, gently insert the fabric strip and clean between the discs with 
a see saw / to and fro action.

In the worst cases, gentle use of a needle to pick & remove the jam may be necessary, but be very gentle and make sure the tension is set at Zero and the presser foot is raised, (to 
disengage tension plates).... do not gouge or score the plates, they need a polished surface to work correctly.

Far less common, but if the loose threads are on the top, it is bobbin tension that is loose, it too may have lint in the spring and be giving a "false" tension. 

I would not recommend fiddling with bobbin tension without good reason, it may end up with missing small screws and spring pieces, however, you can take the needle plate off to clean 
the hook race area (where bobbin case sits) 

...this is just good housekeeping, my wife does this every time she replaces the bobbin....

just take it out and clean the bobbin case and the fixed metal hook race with a small brush to remove lint. If there is a significant amount of lint, use a vacuum and small brush to get the worst.

Then wipe all this area with a cloth or cotton bud (Q tip) moistened (not soaked) with methylated spirit, especially if there appears to be fine dirty deposits....oil and lint combine to conspire against you.

If it seems likely that you ......really .....actually .....need adjust the bobbin case, first check there is no lint trapped in the metal spring where the thread is tensioned. 

Drop-in Bobbin case will look similar to this image with the tension screw in the middle of the metalwork....

4c76dc1.jpg ...the other screw at one end is holding it all together, so is not a tragedy to undo the whole lot and clean it, but very gingerly and lay the bits out in sequence and orientation, or you risk tearing your hair out !

....this is a bobbin case from a front loading machine and works in a very similar fashion to the top loader with drop in bobbin, again, if you dismantle it, take care so you can put it all 
back properly.
165ca5c.jpg FINISHING UP
When you are certain there's no trapped lint in top tension or bobbin, set the top tension to 4 and the bobbin tension to a point where you just begin to feel resistance.

Try using good quality thread of contrasting colours so you can more easily spot the changes.

Set your zigzag to one width less than maximum (eg. 5 of 6 ...or... 4 of 5 etc) and sew a sample for a few inches and check the result.... adjust the bobbin tension screw very little at 
a time, perhaps 1/16 of a turn.

You may find you are playing with this balance for some little while and if you are putting the needleplate on and off each time begin to think it cannot be correct to do is, 
and eventually, you do get a "feel" for the correct tension and then it happens quite a user you won't be doing it very often unless there is lint built up (or are there small hands at work around the house !?!?!)

If you live near the ocean as we do, salt air can play havoc with metalwork inside and out, so to help minimise this, keep a few small packets of dessicant (silica gel) in your machine case ? then make some sort of cover ! 

Same applies in any damp or humid environment, keep your machine dry and dust free.

Budget for a proper full service every couple of years (more often if heavily used) and if you don't use your machine for a few years, be aware that old oil will dry out and combining with 
dust and form a "clag" like glue (another reason for some sort of cover, even a teatowel !)

If it is worth spending the time, energy and money on making something that you would like to give lasting enjoyment......use quality thread, may seem to cost a little more at the 
time, but the results, ease of use and added longevity will be worth the extra, and as a bonus, your tension troubles may be fewer and further between, because there is a more consistent diameter with good thread, and less compensating to be done by your tension plates and less thread breaks !

Posted on Nov 26, 2008

  • 128 Answers

SOURCE: Tension Problem on Pfaff 2034, bobbin loops

Rule of thumb.. Loops on the bottom, problem on the top. Loops on the top, problems on the bottom.

Set your upper tension at 4, and rethread the machine from the top. Just before you thread the needle, but the presser foot down. If the thread pulls right thru easily, then the thread is not thru the tension wheel right. Because, if you can't pull the thread thru with the presser foot down, you have it threaded right.

Posted on Apr 25, 2009

  • 2510 Answers


Check the bobbin tension and that the thread is tight around the bobbin. Make sure that the bobbin is in the right way around - the bobbin thread should double back on itself coming out of the bobbin holder.

Posted on Feb 24, 2011

  • 78 Answers

SOURCE: I have a fashion maker

ok sorry to hear your having trouble check to make sure nothing is caught in your tension disk you may have to pull them apart .

Posted on Aug 19, 2011

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2 Answers

Model 525B. Why is bottom stitch loopy and the hand wheel and needle jam?

try a new needle

try adjusting the top thread tension to see if that helps the bottom loopy stitch

Jan 10, 2016 | Janome Sewing Machines

1 Answer

The bobbin thread is loopy on the under side of the fabric. I tried adjusting the tension setting but it didn't help at all.

Loops stitches on the underside is typically from the TOP tension being too loose, however it can also be the bobbin tension is too tight, or a problem with the needle. I would check them in that order.

Hold the bobbin thread and let the bobbin dangle. A slight shake of your hand should allow the bobbin to move downward (lets more thread out) but not so much that it just drops to the floor. When you put it in again and try sewing look at the top stitches. Do they look overly tight? THen the bobbin tension is too tight. The stitching should look the same top and bottom with no loops.

If both tensions seem to be alright check to see if the needle is: 1. the right size and type of the fabric 2. not bent

That should fix your problem :)

Jan 22, 2011 | Husqvarna Rose

1 Answer

Bunches of threads on the bottom

You didn't give the brand, but if it's any of the older, non computerized machines, your problem is most likley in the tensions.
Loopies (tangles or nests of thread) on the bottom means upper tension too loose (or bobbin too tight).
Let's do the bobbin first...once it is set...99.9% of loopies on the underside are a problem with upper tension.
This is for bobbins that load on the front/side of the machine.. Take out the bobbin case...check the area (hook/race area) that the bobbin goes into for lint, tiny thread pieces, etc.). Now, most of this type of bobbin loads into the case with the thread going counter clockwise (when you are looking at the open side of the case), insert the bobbin in the case, and pull it through the hole/slott in the side of the bobbin case. To test for proper tension:
Lay the bobbin case in the palm of one hand, pull on the thread coming off the bobbin case. The bobbin will gently lift off your hand & if you wiggle the thread, the bobbin case should slowly drop about an inch at a time. If it's too tight, loosen the Larger (closest to where the thread comes out) screw on the side of the bobbin case about 1/16 of a turn...tiny bit...retest. Once that is done try a test stitchout. Remember to hold onto the bobbin & top thread for first few stitches.

If you still get loopies on the bottom...tighten the upper should be set between 4-5 for regular sewing.
Make sure the needle is in properly.

For a drop in bobbin...adjusting that tension is harder. You take the face plate (needle plate, the plate covering the sewing area of the machine) off and remove the bobbin case...First...look at the case in the machine...there is a little lip sticking out, usually at the bottom right corner of the open area (closest to you)...this is where you need to have the little lip when you replace the bobbin case.
Remove the case...check under it and inside the machine for lint/dust/threads & using a small paint brush (I use a childs tooth brush sometimes), clean the lint out. Now check the bobbin case for lint, especially where the thread fits..look at the inside of the case, you will see a little flat metal thing with a slott in it...make sure no lint in that slott. I use a pin to remove lint from there. Reinsert the bobbin case, rethread it all, (bobbin goes counterclockwise). Put the faceplate back on & test the stitches...still loopies with the upper set to between 4-5? Then you will remove the faceplate, remove the bobbin case & loosen the screw on the outside about 1/16 of a turn (these are usually covered in a colored coating) and retest.
I know that most home machine makers say not to adjust the bobbin..but that was back when you had one size we have many, many sizes and types of thread, so adjusting the bobbin may be needed sometimes.
Rule of thumb is:
loopies on underside...tighten upper tension
loopies on top...loosen upper tension.
But, like I said...with all the new threads..sometimes you have to adjust that bobbin.

May 12, 2010 | Sewing Machines

1 Answer

Tension issues with the bobbn area

No, I have not had a consistent problem with this.

What looks like a bobbin issue could be a threading issue.

If a sewing machine is threaded with the presser foot down, the tension control does not capture the thread as it should. The top thread then cannot form a proper stitch with the bobbin thread.

If I forget to have the presser foot up when I thread, then I get loose stitching on top and loopy stitches on the bottom.

Mar 30, 2010 | Janome 659 Mechanical Sewing Machine

2 Answers

Tension problem

Set the top tension as recommended by the mfg - this is usually between 3 - 6.

Now re-thread the machine with the presser foot up and see if this doesn't eliminated the loopy stitches.

What appears to be an issue with the bobbin may actually be the top thread was not seated into the tension during threading and the tension cannot control the flow of thread to the needle and you get a loopy stitch.

Keep the bobbin case clean as built-up lint can cause stitching problems.

Feb 20, 2010 | Brother LS-2125 Mechanical Sewing Machine

1 Answer

Seting the bobbin tension on brother xl-5600

loopy underside means upper tension and or threading is wrong

Jul 02, 2009 | Sewing Machines

1 Answer

Bobbin stitch is loopy

4 is the "middle of the road" tension number, but it depends on the thickness of your fabric.

Jun 15, 2009 | Singer 132QRFB Mechanical Sewing Machine

2 Answers

Tension Problem on Pfaff 2034, bobbin loops

Rule of thumb.. Loops on the bottom, problem on the top. Loops on the top, problems on the bottom.

Set your upper tension at 4, and rethread the machine from the top. Just before you thread the needle, but the presser foot down. If the thread pulls right thru easily, then the thread is not thru the tension wheel right. Because, if you can't pull the thread thru with the presser foot down, you have it threaded right.

Apr 24, 2009 | PfaFF Tiptronic 2030

1 Answer

Thread or bobbin tension

Thread tension. Beware of adjusting the bobbin screw. Pfaffs maintain their tensions just fine without adjusting the bobbin tension, unless you're using some crazy thick or fine thread. If you must change your bobbin tension, you would be well-advised to buy an extra bobbin case, because re-calibrating your tensions after changing them can be less than fun.

Increase your top tension, and your looping should cease. I normally keep my tension around 4.5. Also make sure you're using a good quality thread, and that there's nothing in the upper tension assemblies. Sometimes a tiny piece of debris can keep the top tension from applying enough tension, so turning the machine off and blowing some canned air in there can help as well.

Good luck,


Mar 10, 2009 | PfaFF Creative 7570

1 Answer

Loopy stitches on the back

I have no real solution for your serger, but keep in mind that stitches on the bottom of the work reflect upper thread tension problem, while top stitches are a problem of the bobbin tension( FOR THE MOST PART)

Oct 13, 2008 | Juki MO-644D Mechanical Sewing Machine

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