Consistently 1/16th of an inch off!
 

Hiya!
I just finished the Quiltworx Dresden blade 18" square. My first paper piecing project (Craftsy unlimited).
The first two blades joind perfectly. Every blade afterwards was a consistent 1/16th of an inch off.
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I checked my seam allowances - I sewed perfectly on the line, and had a perfect 1/4" seam allowance. I measured Multiple times during the process. I used my purple thang and a ruler to check 1/4" from stitching to the edge of the fabric. Disgruntled with the lack of perfection, I decided I'd not do the other three blocks (more fabric for my stash <sigh>) and moved on to the Pat Sloan pineapple quilt for my daughter. Instead of making a bazillion 2.5" squared, I joined multiple 2.5" fabric strips to give the pineapples a scrappy look. (DD has requested a gray background)
Each section of the 4 2.5" squares sewn together are exactly 1/4 inch shy (totaling 1/16th off on each seam!). After calculating the 1/16" per seam loss across the entire width/length of the quilt, this means, upon completion, I'll need to add a 4.25" border to have the quilt come out to the expected size.

Has anyone experienced something like this before? I mean, at least I'm consistent... I've taken great care w/my cuts, I measured the wazoo out of all my seam allowances on the pineapple stuff - and I'm still facing that 1/16th of an inch issue.

Your wisdom is Much appreciated!

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Are you measuring the actual seam allowance, or are you measuring the block itself after you sew it, to see if you are getting the correct block size? There is a difference, and the more accurate way to measure your seam allowance is to sew 2 blocks together and measure the finished size, which should equal the sum of the two blocks minus half an inch.

In other words, if you sew together two 2" blocks, your finished patch, measured across the right side of the fabric, should measure 3.5". 2" + 2" = 4", minus half an inch, is 3.5".

Also the thickness of your thread will make a difference, especially if you're "using up" some 40 wt.

I did have an Olfa ruler that was 1/16th inch too wide. Fortunately I had been using it to draw and spotted the flaw before I used it for quilting.

You may need to make your seam allowances "a thread or two" narrower.

Or you may need to cut your pieces "a thread or two" larger.

Or - if you printed off patterns, the printer may be "off" a bit and distorting the pattern. A lot of patterns have a "verification square" to see if it is printing "true."


A "test sample" that I have found effective:

Cut three strips "your" 2 x 5 inches.

Sew them together using "your" 1/4 inch seam

Press like you usually do.

The center strip should "show" 1.5 x 5 inches and the unit "should" measure 5 x 5 inches.

If it does not, then you need to figure out where you need to make adjustments.

Sometimes a "thick" thread will also cause the unit/block to end up small.

Did your needle move over a bit? Is your presser foot tight? When you copied the paper piecing sheets, was it off a little? They usually give a 1” box to check for accuracy in copying? It doesn’t sound like you used rulers but if you did, where you rotary cut on the line can matter, especially if it is not a fine line.

As Peckish said, we talk about a 1/4" seam, but you don't measure the seam, you measure the resultant patch. Keep moving your needle or tape or whatever you use for a guide until the patch measures the correct finished width. Also, this can be a moving target. Your fabric and thread choices can affect it. It's best to double check at the beginning of a project and make any adjustments. One other thing to check is that you are not pressing a tiny pleat into the seam with your iron.

Personally I would not be worried as all the blocks are the same - even though 1/16" smaller than the desired size. The problem to me would be non consistency with some the desired size and others smaller. As you say add a bigger border and no one would be any the wiser.


Good luck on getting it finished and don't forget to show us.

Your blocks are beautiful! What machine are you using for piecing? Make sure the needle is set to center. Some stitches are left or right of center oriented.

As mentioned above, thread takes us space too.

nope, not using up 40wt, Every time I turn the machine on, I re-measure the seam allowance. Just because I'd never paper pieced before, I measured the "2 inch" gauge on the paper after printing - spot on @ 2". However, reading Paper Princess' & Peckish's comments: I always thought the 1/4" seam meant 1/4" from the stitching to the edge... argh! :)

Well, I measured the blocks. They should be 2" (2.5" - .25 per seam *2). Nope. They are 1 and 15/16ths of an inch... not TWO inches. This is driving me insane! LOL But, I'll accept this and continue on w/the Pineapples. LOL
I'll probably crank out some mug rugs and see if moving my needle one click to the left would make the difference - if so, I'll know fo' sho' when I start my next project. LOL

Rhonda K -The machine I'm using for piecing is a Brother CXLA155 - a 199.00 Laura Ashley edition. It's been pretty solid for such an inexpensive machine - but I have noticed the presser foot is a bit "wiggly" when the foot is lifted. The screw where it joins the shank is tight as can be, that part doesn't 'wiggle' - just the foot wiggles - not much, just enough to notice you can wiggle it (if that makes any sense...). I wonder if that wiggle might be my culprit? I bought a nice set of universal feet (28 in a box) when I got my machine. I have duplicates of every foot that came with the machine. When I do a mug rug, i'll try that other foot (the no-name brand foot) - and keep the settings the same/measure, blah blah blah - and if it solves the problem I'll let y'all know. Never even considered the foot being a possible issue... The other issue I have, is if that needle is set to center, to sew a proper 1/4" seam (or what I measure as 1/4") - my fabric edge would be under the foot, not at the edge. :(

Thank you, Busy Fingers, for the encouragement to move forward. I've made one quilt and a lap quilt, so this is my third-ish, and I couldn't see why the shortage would hurt anything, as long as I were consistent. I appreciate the confirmation from someone experienced!

Now my question - is a 1/4" seam allowance from the edge of the stitching to the fabric edge, OR, is it from the stitching to the edge of the fabric?
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A quarter-inch seam is where ever you have to place the fabric to get a true quarter-inch seam.

That's not very helpful, I know.

You're going to need to sew some scraps, then measure the finished patch to get the correct finished size before you can know where to place the edge of the fabric with regards to your foot.

I agree with Peckish. Don't mess with measuring the seam, measure the finished blocks on your sample to see how accurate you are. I used to measure the seam and it was never accurate. Once I started making a couple sample blocks and measuring those instead, my blocks were much more accurate