I started out quilting, years ago, on a Bernina Artista with my older elna as backup. That's when I discovered 1/4" on one isn't necessarily a 1/4" on all. Unfortunately . . .even using two different brands of quilting rulers can throw off a project as well. I think the problem could be the measurement system. In the US, we use imperial measurements while the rest of the world uses metrics. So when making feet, the imperial measurements can be off.

There is a difference just slightly between my two Berninas even tho they are both from the same series. The difference is the width of a thread so I always make sure I start and finish the blocks from a quilt top on the same machine. Doesn't matter with borders and binding.

i use my feather wt to take w to quilt group meets etc. the needle is not moveable. been using scant 1/4" foot on it for years. the fixed needle position on it using 1/4" foot results in a <3/8" seam instead scant 1/4" ..so i have carefully placed a small strip of red electric tape at correct scant 1/4" mark (i don't want any tape on the enamal of this vintage beauty). the scant 3/8" is nice for my miniature quilt block piecing tho, so i continue to use the 1/4" foot instead of the regular fw foot that came w the machine. may sound complicated, but it works for me. i have a nice older pfaff at home w moveable needle, & have a scant 1/4" foot that i use on it also. i use a drafting ruler, set needle on 1/4" line to verify what my seam allowance truely is on any machine i am using, instead of relying on what the foot is.

I never switch machines when making a quilt. One thread or two can make a heck of a difference. I use my featherweight. I think it is the best straight stitch around.

When I start a new quilt or change machines, I run the 1/4" test: sew three 1.5" or 2.5" strips of the fabric together. Then measure to insure that the middle strip measures either 1" or 2" and that the block is 3.5" or 6.5" wide. This is necessary because the thickness of the fabric and the thread may vary depending on the materials you're using. It took me a few times of making unequal blocks and ripping out before I realized that the 1/4" mark is not always in the same place. So I think I've got this skill working for me, but I'm still not as accurate with my cutting as I need to be. I try so hard and think I've got it licked, then I'm off just a smidgen. Good luck with you progress.

yes. I've had a width difference on 2 different machines of the same brand. My inexpert analysis came up with two possible causes:

1) One or both of the 1/4" feet are not 1/4".
2) The needle adjusting settings are not identical on machines. Even with the little opening for the needle, I find I have room to move the needle to the left of center, right of center or center on one machine, another machine doesn't really give me a choice - it's a simple mechanical that i use on vacation, and my third machine is, theoretically, calibrated to work like the first one described, but it doesn't.

Make several sample blocks or seams from each of your machines and compare them using a 1/4" seam measure. Make a note of which needle settings are most compatible on each machine and tape them to the machine where you can easily see them and they won't interfere with sewing.