The right sewing machine needle
 

My Juki 600 has been sounding awful, clunk clunk. I've taken the throat plate & cleaned several times this past week, changed the needle every day (I have the organ 100 pkg.) I convinced myself it was helping (grin). I also have the Juki 2010 on a frame ,it also has a Organ 100 pkg. of needles. You guessed it, I've been using the wrong needles. I'm so amazed the 600 sewed as well as it did, except for the clunking sound. I've just finished marking each pkg. of needles with 600 on them. The other needles were not even supposed to be on that side of my sewing room. The sad part is I have no one to blame.LOL.

I am so sorry that you had to go thru all you did. It is difficult now a days to chose a needle that will work best with you DSM with so many needles to chose from. May happy days of quilting be just down the road. Good Luck.