[ATTACH=CONFIG]425036[/ATTACH]It is #37 and I think it is called the Patchwork foot. That foot has a 1/8 inch seam allowance at the front edge as well as the notch lets you know when you are exactly 1/4 inch from the end of the seam. I find this very handy for stopping an exact 1/4 inch from the end when sewing my binding corners.

Most of the time having a consistent seam works fine for me. But a lot depends on the block. If you are making a very detailed block-many pieces, angles, etc.- you do need to have a very accurate seam to get everything to fit right. 9 patch vs mariners compass for example, one you are fine if you are consistant the other, not so much

Technically, the seam allowance doesn't matter at all. What matters is the measurement BETWEEN the seams. In my studio, it is either accurate or it is not, there is no 'accurate enough'. I could care less about perfection, but I'm committed to excellence.

How? there's no reference to which post you're replying to.........

The Bernina foot, right? Can't quite tell in the pic but would it fit on other machines or does Bernina use a different type of attachment?

I try for a perfect 1/4" seam allowance all the time simply because it prevents problems down the line. It is worth taking the time to perfect that seam allowance -- saves so much aggravation!

Having experimented with many methods, the one that *always* works for me is to create a physical guide for the seam. I used to cut adhesive moleskin (available in foot section of pharmacies), but now my preferred physical guide is this one: http://www.amazon.com/Dritz-Quilting...dp/B0085L2Y2I/ . With this in place my eyes are given relief (because they do not need to be glued to a mark on the bed of the machine) and I can sew very fast and still get perfectly even seam allowances.

Also, I have found that using fine thread helps a lot with my seam allowances. My favored thread is Aurifil 50wt 2-ply on top and in the bobbin (or 60wt bobbin thread in the bobbin). I think this helps because the turn-of-the-cloth is able to be ironed with more precision.

Recently I started piecing a kit and forgot to move my needle over one notch for the seam (necessary on my Bernina because of the relationship between the needle and the feed dogs). I did not realize it for a long time, when I went to match up seams and they didn't match. This was because every seam allowance was double a single needle-notch larger than they should have been. I should have ripped all my stitching out and started over! Instead, I decided to "adjust" the pattern as I went. It has been doubling my time at the machine; wish I had started over with the correct seam allowance. The pattern has lots of cornerstones, so it is tedious to adjust a seam every few inches!

In general, if blocks can fit together without ripples, I don't worry too much about exact size. I would guess I can adjust up to 1/4" difference in most 12-inch blocks without a problem. With 6-inch blocks, the tolerance would be closer to 1/8".

Edit: My experience with this quilt kit is proof that having a consistent seam allowance is not enough. It works for specific patterns, but definitely not for patterns that combine blocks with sashing and cornerstones!!!

As ghostrider mentioned:

The important measurement is the one BETWEEN the seams!

After making over 115 or more quilts, 10-15 comforters, and 10 or 15 biscuit quilts. I still can't make a perfect quilt. I keep trying but still can't do it. Lots are close but, no cigar.

all I know if it is cut correctly , sewing is a whole lot easier and it also looks better when finished