Scant quarter of an inch
 

I hear and read about this all the time. We are also told to do 1/4" seams.

What is the difference and why do we need to do scant 1/4" ? How scant do we do 3/16 or 2/16 so confusing.

will a pattern size be affected by always doing 1/4" rather than a scant?

where did the scant 1/4" come from?

help I'm so confused.

Scant 1/4" is confusing to me also. I have heard so many discussing the difference, but what difference does it make? If all seams are the same size, the blocks will all be the same, right?

I agree with the consistency of seam measurement vs making yourself nuts about trying to achieve a 'scant' anything. Scant is (at least my understanding) a couple threads shy of 1/4". Why??? If your pattern needs to be that precise - use paper piecing (mariner's compass type comes to mind). Otherwise, for me, as long as my seams are consistent and things fit together correctly, I'm good with it!

I have done scat 1/4" seams when doing very small minature quilts. It just leaves a tiny bit less bulk on the seam allowances.

Well, I get an error this morning on the search function but I'm pretty sure we have had several recent discussions on this - there are some methods for getting this, and some folks don't worry about it. I don't but then again I rarely make anything that isn't strips or squares or half square triangles. They all seem to work with a 1/4 inch seam.

I also hear talk about this a lot - and apparently if a pattern calls for it, you are in trouble if you don't do it right. For me.....life is just way too short for this kind of stress. Just MHO.

I believe, as i have done it for many years, that as long as you use the SAME seam allowance for the entire piecing process, that's what matters. I have never used a purchased pattern - just make my own from blocks i like - and I use the edge of my presser foot as my seam guide - it gives me a 3/8" seam.

There is one caveat to this......Dresden plate....or any of the patterns that form a "circle" out of wedges - because you have to keep the 360 degrees correct or it will fail.....in those cases i mark the 1/4" seam line with a light pencil and stitch on the line...goes quickly and accurately.

Rather than drawing a seam line on the fabric to get your 1/4" why not put a strip of masking tape or something on the machine bed 1/4"away from your needle to give you the right measurement, then you could do all of your piecing with the recommended seam allowance.....

Being consistent is sometimes enough, but not always. If you're doing a quilt consisting entirely of 9-patch blocks, for instance, you will be fine with any size seam allowance. However once you start mixing in angles or blocks that have different numbers of seams, you need to patches that measure correctly in order to have the whole thing come together accurately. Quilt patterns are designed with a 1/4" seam in mind, but the theory underlying this is that you're living in a 2-dimensional world. However, fabric and thread are not 2-dimensional; they have some thickness. When you take two patches that are 2" square and sew them together with a seam that is exactly 1/4" you hope to wind up with a rectangle that is exactly 2" x 3.5" (losing 1/4" of each 2" square in the seam). However you are going to wind up instead with a rectangle that is 2" x something less than 3.5". How much less will depend on the thickness of your fabric and thread, because these things cause some of the fabric to be "lost" in the seam. This is why the "scant" 1/4" is important, and how scant depends on the thickness of your fabric and thread and how well you can press the seam flat (which again depends on the fabric and thread).

Even if there were no need for a "scant" 1/4", being consistent is not enough when you are dealing with more complicated blocks. Suppose you decide to sew 1/2" seams instead of 1/4". If you make a 9-patch it looks fine. If you make a 4-patch it also looks fine. But now take a 9-patch and a 4-patch that were supposed to be the same finished size and try to put them together. It won't work, because there are 2 seams going down the 9-patch and only one seam going down the 2-patch! This is an exaggeration, but the theory holds even if your seams are only 1/16" too large or too small.

The lesson to take from this is that you need to measure your block as it is formed to be sure your units are measuring correctly. The seam size needs to be adjusted so that the *finished* patch is the right size.

Block pattern measurements are given for 1/4" seams. It's the standard size for quilt seams. If your seam is bigger or smaller the block will not measure the size as the pattern states. A scant won't make that much difference but each seam has to be the same either a scant or 1/4". Thread weight plays a big part of the scant and full 1/4" seam.