Brother has a few '6000' models. I have the cs6000i. Are you talking about how there seems to be a very slight 'twist' to each stitch when using the first straight stitch selection (01)?
Try setting the stitch to 37 or 38 for piecing. Those look 'straighter' to me.
(Course, check your manual for correct stitch # as it may be different if your machine is a different 6000 model.)
I am really enjoying my machine also. I've been looking for new-to-me projects just so I can try out all the different stitches and presser feet that came with it. :)
Hope that helps!
Cathy

My model is the cs6000b. Yes, the stitches have a twist to them. When you select #37, what number do you use for stitch length & width & also the upper tension control dial? I know a set number will not work for all fabrics but I need a place to start. Thank you for taking the time to answer my post!
Janet

I see that's the same machine, just different package features. :0
I've just used the preset stitch length and width (1.6, 5.5) and had the tension on 3.
You are so right that it won't work with all fabrics, so it's always a good idea to test it out on scrap pieces of the fabric you will be sewing. And I've found it very helpful to test the machine on scrap any time I've cleaned it or changed bobbins.
Hope that helps.
Happy Sewing!
Cathy

I had the tension on 7 so I will try lowering it. Thank you so much for all the great info!!
Janet