Can someone explain to me how you judge a scant quarter inch. I'm fairly new to quilting and this phrase kinds scares me. How do you judge what scant is?

The best way that I can explain it is - sew just inside the quarter inch line. A quarter inch is 4/16 (on the ruler). Sew between 3/16 and 4/16 as marked on the ruler.

I have heard that it is one or two threads shy of a quarter, but I personally think it is hard to judge.

I judge it by 2 or 3 threads from ¼ in line. I place a piece of painters tape about 1½" long close to my needle to help me be consistent.

It's different for every sewer and every machine (and depends also on fabric and thread).

Basically what you have to do is test until you get it right. Cut 2.5" strips of fabric (maybe 6" long). Sew 3 of the pieces together with what you think is a scant 1/4" seam. Iron, then measure. With perfect 1/4" seams, the piece should measure 6.5". If it's less than that, then you need to reduce your seam width and try again.

Here's what I do to achieve perfection (ahem.....). I take one of my cutting rulers and place it under the presser foot of my machine. I lower the needle until it touches the 1/4" line, but then move the ruler slightly so the needle touches just a little to the side of the ruler's 1/4" line. I lower the presser foot to hold the ruler in place. I also check to make sure that the ruler is straight from front to back. Then I take a strip of moleskin (that I have already rotary cut), peel off the paper backing, then stick it to the base of machine right next to the ruler's edge. (Moleskin is sold in the foot section of a pharmacy. It is a thick adhesive-backed material used to protect feet blisters.) The moleskin provides me with a physical guide for feeding my strips into the machine so I don't have to stare at a mark.

At this point, you should test with the 2.5" strips to make sure the end result is accurate.

Instead of a ruler, you can use graph paper that has 4 squares to the inch.

The reason for the "scant" seam allowance is so the end result will be the correct measurement. Seams require some turn-of-the-cloth that uses up a little bit of the fabric. If the seam is an exact 1/4", then the end measurements after pressing and many seams will be short. Also if you are using thick fabric and/or thick thread, the turn-of-the-cloth will take up even more of the fabric. Better to take a little off each seam than to end up with a block that is 1/4" short from all the seams in it.

I personally think this scant business is just to make you crazy. I sew a quarter inch. One of my latest quilts had 159 seams along the length. When I measured for the border the overall length was off less than one sixteenth of an inch. This is were don't sweat the small stuff comes in.

Kat, you must live right!

I use a 1/4 inch foot and move my needle over one or two spots.

Well Said!!! I think as long as you're consistent it really doesn't matter. Or at least it hasn't in any of the projects I've done so far. :)

I agree with Kat and Rachel. I don't think it matters so much as long as your cosistent with the 1/4 inch it self.

Tutorial here:
http://www.quiltingboard.com/t-89997-1.htm
you really do need to figure out where on your machine this is. If your quilt is made up of all the exact same blocks, then just being consistent will be just fine. As soon as you try to piece one block with 3 seams next to a block with 2 (or 4 or 5) seams, you will start to have problems.

The quilt that was off by less than 1/16 inch would have been accurate regardless of how many different styles of blocks were in it. I did the math first to determine the correct size (13 8 inch blocks plus one 3 inch piece to balance the frame plus 2 unfinished edges equals 107.5 inches) and the measurement was within 1/16 inch. I like to enjoy quilting and am glad I don't have to stress over 2 threads.

That's just not true. All of the blocks will be the same size, no matter what blocks you make, if your seams are consistent. The seam width may, or may not, affect the final size of the blocks, but they will all be the same no matter how many seams are in them. Otherwise you'd never be able to make any quilt with more than one type of block in it.

I never use scant seams and it's never made any difference worth mentioning, in fact it makes for flatter, squarer tops and a much happier quilter when they're done.

It's true that the size of the seam will not matter as long as you are making a quilt out of all of the same block pattern, or all of the same block pattern alternating with plain blocks.

Problems arise quickly, however, when you want to make a quilt that uses multiple types of pieced block. The most obvious example would be a sampler quilt. Even if your seams are a consistent size, every block may end up a different size because their patterns are different.

I'm trying to think of two block patterns that would illustrate this clearly, but my mind is blank. I found this article that tries to illustrate the problem:
http://www.scrapquilts.com/accurate_seams.html

There isn't so much of a problem when you are dealing with squares. The problems start to become more obvious when making blocks with star points.

I'm thinking there would be problems even with a feathered star if you cut all the pieces out first. If the star strips are not sewn with the correct 1/4" seam, they will not fit the already-cut center squares. If you know this in advance, you can make the strips first and then cut the squares to fit the star points. However, again you may have the problem of the feathered star block not being the same size as another block featured in the quilt.

Those of you who have not had a problem probably are using scant 1/4" seams without realizing it. Since all block patterns are sized assuming an accurate finished 1/4" seam, all block patterns will come out the same size for you if you happen to be using a scant 1/4" already.

I am quite sure my Grandmother and Great-Grandmother never heard of a scant 1/4 inch. All of their quilts are beautiful. Grannie pieced and quilted 10 stitches to the inch. I do not think I will ever get there! LOL