Thread is balling up on the bottom trying to hem pants with straight stitch

Do you have the bottom bobbin inserted correctly and fully seated?

Are you absolutley sure you're not getting a problem with stitch formation on, for example, wide zig-zag. Check again, using a different colour top and bottom and make sure that the stitch is being formed properly with only the top colour on top and bottom colour on the bottom. It sounds as though the bottom loop is not being picked-up by the hook properly. Make sure you've thoroughly cleaned-out any fluff under the stitch-plate and remove the hook/shuttle and give the hook race a good clean and give it a single drop of oil, even if you've got the lightweight part-plastic hook/shuttle fitted.

You haven't said what mail and model machine this relates to.

You could try http://sewing.about.com/od/sewingmachineindex/tp/operatingasewingmachine.htm, there is lots of good general information there which might be of help, most machines have similar functionality, ie a bobbbin goes into a rotary hook and there will be a tension spring on that thread. Top thread will also need to go through tension device, usually discs in the threading path from spool to needle.

There is usually a stitch length and stitch width dial/knob/digital selection and a stitch selector for different utility stitches such as blind hem, overcasting etc. If you just want a straight stitch, then stitch length would be 2.5 or 2.7 maybe for a heavy fabric.

You need to put in the correct sized needle for the fabric you at sewing too, http://sewing.about.com/od/sewingmachineindex/ig/Sewing-Machine-Needles/

Important thing is threading up so that both threads are under tension, make sure the pressure foot is raised during threading so the top thread can go between the tension discs. The bobbin will either be drop in top loading in which case you need to click the thread into a tension spring on the side of the bobbin holder. Or front loading bobbin inside a removeable bobbin case which is mounted vertically. The bobbin case will also have a tension spring on it.

Also you could try You-tube - there is lots of videos there for different brands.

If your machine has been stored for 5 years, you should give it a good clean and oil according to the manual before you do anything else. Then put in a new needle and wind a fresh bobbin, checking that the bobbin has been wound smoothly as a badly wound bobbin can cause poor tension and stitching from the bottom thread.

You want the thread to go from the spool through a tension disc or eyelet to the bobbin and keep some gentle tension onto the thread spool using your scissors handle or similar so that the thread winds off it smoothly and the spool doesn't bounce around. Also give the thread a nudge with your finger tip as it winds onto the bobbin so it fills evenly, top, middle and bottom, not all in the middle.

Are you wanting a straight stitch to sew around the hemline? If so, your stitch length is right, but stitch width should be zero. You don't say what knob is set to 4, if its your top tension then that should be close, usually between 4 and 6 if dial goes from zero to 10.

Which thread is too tight? top or bottom. Firstly check the threading path to ensure that the top thread isn't catching on anything, is through the take up lever properly and coming from the thread spool without catching there. Some thread spools have a little knick in the top where you can catch the thread to store it, but you dont' want the thread to catch here when seaming, so turn it around the other way on the spool so it can't.

Try test stitching a medium zig zag stitch on scrap fabric, and you'll be able to see if the bottom thread is pulling in or the top one, then adjust the tension dial a little to lessen this.

Hope these pointers help, if you can't get a good neat stitch after trying these things, then consider taking it for a clean and service, the technician can get inside and clean the machine thoroughly and also check for any other issues that might be there.

Hi! Sounds like you're doing everything right to me, so let's see.

By not getting a straight stitch on the bottom, do you mean that the bobbin thread is loopy? If so, then most likely you have to reset the tension. Get a scrap of jeans material and practice on that....it would be great if you could use different color threads on top and in the bobbin, but that might not be practical if you don't have the jeans thread in different colors already.

You'll be adjusting the top tension, because even tho the top stitch looks perfect, it may not be tight enough to pull the bobbin thread up into the fabric where it belongs.

Sew a couple of inches on your scrap, then stop and check the bobbin thread. If it's loopy, you can also see the top thread on the underside. (Which is why using two colors is helpful.) With the pressure foot down, tightened the top tension just a bit. Sew a few more inches and check again. Keep on sewing, checking, and adjusting until you can't see any (or almost any) top threads on the bottom or bobbin threads on top.

Here are a couple of other ideas to check:

1. Make sure your bobbin is inserted correctly. If I happen to put one in backwards by mistake, the bobbin will make a lot of clanking noises.

2. Using your flywheel, lower the needle all the way through the stitch-making process to see if it's hitting anything along the way.

3. Oil your machine.

4. Make sure all the screws etc on your throat plate (also called needle plate) are tight. (I've had mine get loose and that will definitely throw a knock into the works!)

Check out these ideas and let me know if anything works, or if the problem is still there, ok?

Happy Sewing!

Robbie

You do need an oiling and cleaning. Also, try adjusting on the bobbin cover by turning th little screw with a small screwdriver. Keep adjusting and testing until you get the loops just as you want them...

Could be a tension issue.

Try this to see if it helps:
Remove top thread.
ALWAYS RAISE the presser foot and rethread from the beginning.
Start the top tension set at the midway point and then adjust.
Check that the bobbin is threaded and installed correctly.

Understanding Thread Tension Threads

Sewing Lesson 10 How to Fix Tension on Your Sewing Machine

Sorry, I don't understand just what you mean by "length to start". Length of what - stitch? hem turn-up?
Let us assume you are taking up a hem of a pair of pants. Try them on and put a pin where you want the hem to finish i.e. this will be the bottom of the pants. Take pants off, turn them inside out (careful that your pin does not fall out!) and fold the excess pants on that pin mark. The excess fabric should be on the outside, not tucked inside the leg tunnel. Measure how much it is from the existing hem to where you folded it over, let us say for the purposes of this exercise it is 4 inches. Your hem is to be 1 inch and you need 1/2 inch to turn under for a neat finish, total 1 1/2 inches, so you need to cut off 2 1/2 inches from the bottom of each pants leg. Fold 1/2inch at new leg bottom (wrong side of fabric to wrong side), press, fold 1 inch hem same way and press. Place pins every 2inches or so at a right angle to the hem edge. Pins should come out 1/4inch from edge of hem where the 1/2inch neatening fold was made (this is where I wish I could draw a picture!). Fold the hem back inside the leg tunnel. The pins should make the fabric fold under only enough so that 1/4inch of the hem sticks out beyond the pants leg. You will sew on this bit using the blind hem stitch (04 on my 7550). You might need to adjust the stitch width - not length - so that the straight part of the stitch goes along the hem bit and the zig-zag JUST bites into the pants leg fabric.
I do hope this lengthy explanation is of some use to you!

Get in touch with the store!

Sometimes when I need to use heavy thread for top stitching to reinforce a seam that has come undone, I will use the heavy thread on the top and regular thread on the bottom. I haven't tried it the other way around for hemming but I would think it would work. I do not currently have a Bernina.