My sewing machine wouldn't use 40 wt. thread. It kept breaking after 10 seconds. Time after time. I had to change to 50 wt. cones. I wrote about it here. I wrote about it on the Bernina board. It went on for 2 1/2 years. I kept asking about it and complaining about my machine for 2 1/2 years. I quit using spools and used only 50 wt. cones.
Yesterday I took my machine to my dealer because it was clacking and the screen said to take it to the dealer. Well, I had not used it in 3 weeks! I told him, "Watch, it will work fine for you." He plugged it in and it worked fine for him. Why do things do that?
I told him about the thread. He asked what size needle I had in. I said 80. He said "no, no. You need 100 for 40 wt." He put in a 100 needle and put in some 40 wt. thread and it SEWED on my machine like nobody's business!!
It was because I was using the wrong size needle and I never knew that! Boy, do I feel like a dummy! I've been on this board a long time, but I don't recall reading about the bigger needle for the smaller wt. thread. I'm sure it's been written, but I must have overlooked it!
Anyway, today I am setting up my trusty machine and starting on Jenny Doan's Big Block Star Quilt. I am making 2 King quilts. I ordered 4 of her layer cakes she used in her YouTube video. And I bought 3 yards of cream for the background. I have been ready to go forever!!!
I'm sure everyone else knew about putting a bigger needle (100) in a smaller wt (40) thread. But, in case you don't, know you do, just like me. It has changed my life!!!! Truly!