Originally Posted by suezquilts
This has happened with my Bernina, I was told this is a feed dog problem.
One thing I would check is if it is installed right. If you have a instructions, check them
If it works right for the other feet and not that one.. that is the only thing I can think of.
I have put mine on wrong before.
I agree. Make sure that it's all the way on the shank and that the fork thingy is correctly installed on the screw that holds your needle. If the fork is not in the right spot the feed dogs on the foot won't coordinate with the feed dogs on the sewing machine and will throw the stitch length off. Oh, you didn't drop your feed dogs, did you? they should be up with this foot.