My machine is not stiching

SOURCE: Brother 925D - threads do not lock

threads do not overlock stich

SOURCE: Elna SU missing stiches and breaking thread

it sounds like the needle hook timing is out. You need to get the needle in the lowest position and measure the gap from the needle to the hook point on the bobbin shuttle. It should be 1/4". You will need to remove the foot and foot plate to be able to see. I use a 1/4" drill bit as a gauge. If you need to adjust it, you will need to remove the free arm cover to the right of the foot and loosen the 2 allen head screws that hold the drive gear. Adjust the gap, tighten the screws and retry. Usually if the needle catches the thread to early, it will make a bad stitch and the upper thread will break. If it catches to late, it will make thread loops and the machine will skip stitches. Good luck, these are a good machine and worth fixing. Phil

SOURCE: threading

i hope this can help go to this website http://www.sewwhat.net/millie/Manuals/CEX300k.pdf
good luck

SOURCE: I have a singer futura ce-250/ce-350 machine.

I have been sewing for quite some time on other machines. I assumed I knew all that I needed to do and I have the same problem, bunching undeneathe. I found out my problem was twofold. One when you thread the top part - you should pull the thread back and forth in the top thread guide. (#1 in the manual page 6). The second thing was the curly tail in front. It really needs both of these. I hope this helps you. Made me feel really inexperienced. I actually pulled out the manual.

SOURCE: Upper thread knots up with bobbin thread when sewing a stich

Thread test
Test your thread quality to start, thread your machine and LIFT the presser foot (this opens the tension disks). Pull your top thread straight back. If you feel no tension no mater how much thread you pull, your thread is good. If that your machine passes that test, then let me know, we can go to step 2. If not, try different spool of thread, same test until you get a smooth pull (tip: always check your thread this way when you thread your machine)
Step 2:
Pull on your threaded bobbin thread while it’s in the machine. Does it pull smooth and even? If so, go to step 3. If not, try a new bobbin (bobbins get bent or distorted if wound too tight).
Clean thoroughly in the hook and bobbin case area and oil 1-2 drop is all.
Thread knotting on the bobbin can be a lot of things but here's some guidance:
Tension:
If the thread is loose on the bottom of the fabric, it's actually the top thread is too loose. Think of 2 little elves playing tug of war in your machine, one on toip and one underneath. If you have loops on bottom, the top needs to pull harder (tighten top tension)
Jamming bobbin case:
If it is damaged from turning out of place once, it could have rough spots on it that makes the thread hang on it, and keeps making it turn over and over. Use a finger nail board (fine sanding) and smoothall rough spots. Then reset the bobbin case taking care to put the notch in the bobbin case in alignment with the proper spot in the machine (basically 5 o’clock) when looking at the round area where the bobbin case goes.