Is it a zigzag machine? I just went through this with my GD. She needs a guide of some sort for a 1/4". Moleskin or a screw on metal one are her favorites, but on the ZZ machines, the guides covered too much of the feed dogs and the seam wouldn't stay straight. After trying three machines, I pulled up a 1940s Necchi and the problem was solved.

Some machines have the feed dogs spaced further apart than others and this makes it hard to get the "perfect" 1/4" seam. I find I need to adjust the needle placement to the right or left so that the fabric is over both feed dogs.. I then re-measure and mark the location. I have the Janome 7700 and I use the accufeed for most of my pressing and I have found that the presser foot that is wide enough that I can simply align the needle so the outside of the presser foot is my scant 1/4". I use a ruled 3x5 note card to measure my 1/4" -- the lines are 1/4" apart.

I used to have the same problem until I read Sally Collins "Mastering Precision Piecing". My problem was two fold ... one was in starting the seam, the other was in continuing the seam.

When I started a seam I would put my foot down, put the fabric up to the edge of the foot and start to sew. Sally taught me to always start with the needle in the down position, lower the presser foot, raise the foot ever so slightly (enough to get fabric under but not enough to disengage the tension) and butt the fabric all the way up to the needle then slide it over to the right until it's at the correct 1/4" position, THEN start sewing.

When sewing a seam, especially strips - guide the fabric with your left hand (splayed hand - thumb in front of needle/foot - little finger in back of needle/foot), and feed the fabric with your right hand with the fabric slightly raised off the bed of the machine in front of the foot.

Also ... I too use a 1/4" guide but I always adjust my needle position to get the right seam allowance.

Finally ... I use a 1/4" walking foot almost exclusively when I piece. I have a Janome 6600 with the built in walking foot, which was one of the biggest reasons I purchased that machine. I absolutely love it. The walking foot helped, but I still had some issues with uniformity of my seam allowance until I employed Sally's techniques.

It helps me if I always grab the top and bottom thread and hold it with my right hand so the needle doesn't "eat" the fabric and it seems to keep the 1/4" that I want, instead of wandering off.

I will check the feed dog position. I had overlooked that as being an issue. Yes the needle is positionable so I will see if moving the needle position helps first. I can get the seam, it just takes forever to sew because I am having to focus on each stitch. Especially since I was taught to adjust the fabric before it gets to the needle instead of at the needle. It really messes with my "mojo" :)

Thanks for all the advice and tips! I have been using the graph paper but the lines are a bit wide so I will give the index card a try, especially since it is stiffer card stock.

Machine is computerized so I have lots of stitches, but only using my basic straight stitch for piecing.

I will give it all a try next time I scrape away some sewing time. Thanks again!

ahhhh that makes sense....

Do you have or can you get a straight stitch sole plate for your machine? You don't mention the brand. A single hole for the needle to go through when straight stitching instead of the ZZ slot made all the difference for me. Just don't forget to switch back to slotted plate before zigzagging. I solved all my problems when we started collecting and sewing on vintage straight stitch only machines.

Take a couple of large pieces of scrap fabric (muslin is fine), get the stitching started so the threads don't bunch up, then let your machine sew without you guiding the fabric at all. See if it sews in a straight line. What I suspect is that your machine will stitch a curved line (in really bad cases, it can sew a circle!). If your machine does this, take it back to the shop and explain that the feed dogs are out of alignment. This is something they should have checked and fixed at the annual check-up/cleaning, so they should not charge anything additional for fixing this. It seems to be common for techs not to check out *everything* on a machine during an annual check-up.

Edit: Just caught up with the other posts. Wanted to add that you really do want the feed dogs covered with fabric, even if it means re-positioning the needle.

I agree--I had this happen once, and it was because the pressure of the foot was too great. Once I loosened the pressure on the foot a bit, no more twisting. Try it.

I use a stiletto to hold the fabric in place as it goes under the presser foot.