When using twin needles only one line of stitching is stitching normally, the other line is jumping stitches. I have tried rethreading & changed the twin needle. With the first twin needle the left hand line was the problem, with the change of needles it is now the right side. I have frequently used twin needles before without a problem.

Generally, you would use a straight stitch. Trying a decorative stitch or zig-zag with a twin needle is tricky because the twin needles will hit the presser foot or needle plate if the stitch width is set too wide. Be sure you are using a presser foot with a wide opening.

Stitching Odyssey How to use your twin needle

How to Use Twin Needle on Your Sewing Machine

A twin needle makes neat pintucks if you have a pintucking foot.

try increasing/decreasing the needle thread tension for the added material thickness
use scrap material until you get it right

sounds like the timing is off and will need a service call to get it reset. your local fabric store should know who you can call.

try changing the needle
try rethreading the top thread
do you have a manual for the sewing machine ?

try these suggestions and see if they help
Skipped stitches
1. The needle is not inserted correctly
Remove needle & reinsert needle( flat side towards the back of machine)
2. The needle is damaged
replace with new needle
3. The wrong size needle is being used
Choose a needle to suit the thread & fabric
4. The foot not attached correctly
Check & attach correctly

try changing the needle--make sure it the right needle for the fabic
being sewed
also try rethreading the sewing machine top & bobbin
make sure to use every thread guide
make sure the bobbin is turned the right way in the bobbin case
it's also possible that the sewing machines timing needs to be
checked at a sewing machine shop

try rethreading the machine top & bobbin make sure to get ever thread guide
try chaning to needle, make sure the needle goes all the way into the needle holder-normally flat side goes to the back of the machine
check to make the thread is moving smoothly around the tension dial
if these suggestion don't help, then the machine probably could use a servicing

have you tried changing the needle
try rethreading the machine top & bottom
also clean under needle plate area & bobbin area for loose threads & lint

you can just use the straight stitch.If you want to use a fancy stitch you have to be careful that the throw, as I call it is not too wide as you could break the needles and put the timing out. Also use a longer stitch than normal.Also use the stretch twin needle.

The machine is skipping stitches and is probably out of time. Change the needle, rethread the machine and try it again. If it still skips stitches, try lowering the needle by about 1/16 inch and see if it works better. If the timing is off you should take it to a technician for a complete service.
sewman7