Hello Peter,
you have not said what model you have, make sure the needle is in the correct way round, make sure it is the corect size for the thread, make sure you use a good thread, make sure the needle is not slightly bent, if you do not have a numbered tension dial then you will have to adjust it very slightly each time to get it right, check the needle plate and make sure there are no sharp edges cause by a breaking needle.
drivewithken
May 2010