Can I use a twin needle on a Singer Trafition? It seems to only sew one line of stitches.

Interesting. I looked through the manual and didn't find anything about the twin needle selector. You might try it anyway. Just set the needle to the center position and the stitch width to zero. Leaving it this way should prevent the needle from hitting anything and breaking. Otherwise, contact Singer support.

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 this link out.
Stitching Odyssey How to use your twin needle
or this one.
https://www.google.co.uk/webhp?sourceid=chrome-instant&rlz=1C1CHBD_en-GBGB719GB719&ion=1&espv=2&ie=UTF-8#q=How+do+I+use+a+twin+needle+on+a+Singer+4411.+I+would+like+to+know+how+to+thread+a+twin+needle+on+the+Singer+4411.

I just took a look at your user's manual, and boy--you're right, and I've been a computer systems engineer for about 30 years!

Actually, it's easier to figure out by DOING rather than looking at the description on page 35. Basically, selection is divided into two categories--utility, that is, stitches you would use for ordinary sewing, like stretch stitches, zigzag stitches, straight stitch, buttonholes, etc. That is located on the left column, with the arrow keys used for navigation in the middle. The display only shows 5 patterns at a time, so to see all of them, you have to keep pressing the down arrow. Once you have selected the stitch itself, you can then select the stitches width and length, and if it's available for that particular stitch, you can mirror (flip) the stitch, and use a twin needle (if it's available for that design)

The decorative and letter stitches are selected on the right column, and work he same way--they are displayed 5 at a time, etc, and selecting stitch width and length, mirror, and twin needle. However, additionally, you can choose to have the pattern sewn once (the default) or continuously.

I hope that helps!

singer has a free manual in pdf form for the machine, which can tell you if the machine is capable of using the twin needles

Go to the singer website
Go to the home page
Go to customer service--click on it--it will show a small menu--click on instruction manual
In the box put the model number (example w616 ) & click search

Is your bobbin thread actually under tension? check that it is fully into the tension spring, it sounds like its not tensioned fully.

Normally with a twin needle you'll get a little zigzag showing on the underside but the stitches should be secure.

firstly are you using a regular twin needle on a knit fabric? this could cause skipped stitches.
is the twin needle quite old and possibly blunt?

Is the Hobbymatic a model that requires a slanted twin needle, there are two types of twin needles as the computerised machines need the offset style. You can distinguish between them by the plastic block on the needle shaft where the twin needle points are set, either red or a deep brown colour.

If none of the above apply, then it is possible that the timing sequence is slightly off so that one of the needle's thread is not getting caught during the stitching.

Timing is an adjustment that I leave to the technician to address. But if you want to have a go yourself there may be some videos on you-tube for your model and how to make this adjustment to it.

now that is strange. check your thread, now take that twin needle and try this, shove it very hard up into the the needle holder. my thought is that it is not up enough. because your problem is exactly what would happen should the twin needle be sitting too low. try shoving it up higher and test again.

If the needle plate and presser foot are wide enough to accommodate the double needle, then you can use it.

Make sure the needle position is center and the stitch type is straight stitch.

Hand walk the needle at couple of stitches to be absolutely sure all is clear.

It sounds like it needs lubrication on the needle bar frame and linkage.