If you are only going to use a little for a embellishment then your standard #80 needle will work. But you can not use it for big projects

If your project is large and going to stitch heavily for hours in use a #100needle gives plenty of room for that thick thread to move with the least amount of friction

But you have to also be careful as these large needles if too sharp can leave small holes in your project.

But the suggested size is a 90 sharp. But on large projects have seen fraying from friction

Good luck on your project

I agree with genevacarroll . The superior Threads company has a really huge number of articles about many topics, including needle size, how to trouble shoot and tension, cleaning your machine, etc., etc., etc. When you first log in, on the right hand side of the frame, there is an icon labeled "Education Articles". Click on that and you will find MANY, many articles about everything you probably know about machines, thread and other articles. It will behoove you to read them anyway. I learned A LOT from them and admire a site that not only sells, but tries to educate their customers along the way.

I usually use at least a 90 needle, preferably the topstitch needle which has a bigger eye.

Check out Superior Threads. They have a great chart that explains needles and tension for all weights of threads.

geneva

what size needle for 30 wt thread?