Crazy Accuracy Freak Girl has broken out of her cage and is on the loose. I do try to keep her locked up, but she’s a wily one. If 1/16″ or 1/32″ of space that shouldn’t be there between two patchwork pieces that are supposed to match doesn’t bother you, that’s okay–then this post was not meant for you! You quilt your way, and I’ll quilt mine. 😉 However, if you are like Crazy Accuracy Freak Girl and you want to know the really nitty gritty details about how to make patchwork pieces fit together better, and maybe even perfectly on the first try (or you just want to have a good laugh at a quilter gone mad with the need to control literally everything) read on. Continue reading Pinning Patchwork for Perfect Points
Have you ever compared the markings on your rulers to the markings on your cutting mat to see if they are the same? Can you even imagine that they wouldn’t be? Are the markings on your rulers really accurate? Is that inch really 1″?
It never occurred to me that the markings on the rulers might not match up with the markings on the cutting mats, nor that the rulers that I’ve used all these years weren’t really accurate themselves. I mean, why on earth would I even think about that? These things are precision made and we trust them to be accurate, right? Well, I used to anyway.
I found out recently that my trust has been misplaced for many years. I’m having a ruler manufactured to go with my book (yay!), and the manufacturer sent me a prototype to approve. I needed to make some changes, and in doing so, I measured the ruler against one of my Omnigrid rulers, and guess what? One of them was off ever so slightly. I assumed it was the prototype; after all, it’s just that, a prototype, a sample. Maybe it just didn’t get cut right (which was going to be another whole can of worms anyway, but I digress). So I emailed the manufacturer and told him I thought that the prototype he sent me was not the right size.
Unfortunately, assuming did what it frequently does, and made an a** out of me. The manufacturer told me it was exactly the right size, and asked why I thought it wasn’t. I finally got out one of my grandfather’s old stainless steel drafting rulers (he was an engineer, and I figured that one of those rulers would probably be a good benchmark), and compared it to both the prototype and the Omnigrid rulers. The prototype proved to be exactly the size it needed to be to cut accurate fabric pieces, and the Omnigrid ruler was off! Not by much, but the inaccuracy was there as plain as day.
At that point, I went a little nuts, and started comparing the drafting ruler to all my rulers, which are all the Omnigrid brand. The worst of the bunch was the 6″ x 24″, and though the drafting ruler is only 18″, I could tell that the Omnigrid ruler was nearly a sixteenth of an inch longer down at the 18″ end, if the 0 ends were lined up. I truly believe that at some point, this can make a difference in whether your patchwork pieces will fit together as they are supposed to, or need easing and heavy steaming to make it all work out as planned.
When you’re piecing a simple block there probably won’t be any evidence of a problem, but when you’ve pieced 40 complex blocks with many pieces and are stetting them together the inaccuracies add up, and then things don’t go together properly. And maybe, with all of the other stuff going on like 1/4″ seams being accurate (or not), and fabric stretching (or not) and grainlines going every which way, this whole issue with the rulers is just one more bump in the road, but heck, who needs another bump?
In the midst of these maybe-not-so-scientific experiments, I laid the 6″ x 24″ ruler on my 24″ x 36″ Olfa cutting mat, and got another eye-opener. The mat wasn’t even the same as the Omnigrid ruler. For that matter, the mat wasn’t precisely accurate either when measured against the drafting ruler, but it was off in the other direction. 😯 The markings on the mat were actually smaller than they should have been at the 18″ mark.
Now, maybe it’s not quite clear why this was bugging me out so, but I’m getting to that. In general, I don’t use the lines on the mat for anything, and I almost never measure against them, unless I’m working on borders. Borders are soooo long, and cutting them to the right size for the quilt can take some creative measuring and ruler manipulation (I don’t sew them on and then trim!), and I do use the mat at that point to measure the quilt top if I can fit it on there by folding it in half or something. I’ve always figured it was a better bet to measure the quilt top against the mat, rather than with a measuring tape, since those can stretch over time.
So when I measure the quilt top on the mat which is shorter than it should be, but then cut the borders with the ruler which is really longer than it should be, what happens? The borders are too long. Sometimes as much as 1/4″ to 1/2″ too long, and even that small amount can cause waviness in the borders, especially when combined with other issues in the quilt interior that may be giving the whole thing a flyaway look before the borders are even attached. And yes, I’ve noticed this during construction, that the borders are too long when I’ve just cut them according to the measurements. I’ve even gone back and double and triple checked everything to make sure I wasn’t just having a blond moment, but if you use the same tools and method to check your work as you did to do the work, you still don’t get the right answer, obviously.
All these years, I’ve been soooo careful to cut and sew accurately so that my quilts are flat and straight, but I’m still ending up with wavy borders at times, and wondering why. So now I know that I’ve been defeated by the ruler/mat combo. I’d already purchased a new Olfa mat for my cutting table when I discovered all of this, I just hadn’t put it on yet. I decided to measure the new mat and see where it fit in, and it doesn’t measure the same as the Omnigrid rulers either, but it is better (meaning more accurate overall, and closer to the Omnigrid ruler measurements) than the old one.
So what does all of this mean? Well, Crazy Accuracy Freak Girl is blubbering in the corner and will probably be there a while, but as for me, I just need to remember to use either the mat or the ruler to measure for borders or whatever it is at the time, but not both. So check your rulers people, and think about how you’re doing things that might be causing a problem without you knowing. An inch isn’t always 1″.
Have you ever wondered why points are so difficult to match up when you’re making a block with half-square or quarter-square triangles? It’s not so bad if the entire block is HST’s or QST’s by themselves (except that the block will most likely not finish to exactly the expected size), but pair either one with squares or rectangles and expect the corners and points to match up and everything to be sized right in the end, and you’re likely to be disappointed, no matter how carefully you’ve sewn or how accurate your 1/4″ seam allowance is.
Well, I’ve got a news flash for you: it’s not you or your sewing skills, it’s the math. And I don’t mean that you or the pattern designer have miscalculated the cutting sizes either. What I mean is that mathematically, when you calculate the size of square to cut for a certain finished size of half-square or quarter-square triangle, you won’t get a size that’s rotary cutter friendly. It’s some algebraic formula like Asquared+Bsquared=Csquaredyaddayadda, and I did actually do the math a couple of years back though I don’t remember the formula at the moment.
This whole issue can be proven with graph paper as well. Try this: draw HST#1 with 2″ straight sides on graph paper, and then add 1/4″ seam allowances all the way around. Then draw HST#2 at the universally accepted cut size, with 2 7/8″ straight sides (the formula to determine the cut size for a HST is finished size + 7/8″). Measure the straight sides on the HST#1, which should be 2 7/8″, but they’re not. Sure, it’s not THAT far off, but when a block contains 8 or 16 HST’s, or when those HST’s are supposed to fit together with a 2 1/2″ square patch, this can cause issues down the road.
The bias edge across the middle of the HST adds its own measure of instability and inaccuracy, and it all equals wonkyness that’s not likely to be the right size in the end. What to do? I’ve gotten to the point where I cut large and trim down after the HST’s or QST’s are sewn, so that I know I’m getting the right size and everything is really square. I use the formula, then add 1/2″ or 3/4″ to the squares when I cut them. I dislike doing this for two reasons: one, it’s an extra step, and in multiples no less, since how many quilts need just one or two HST’s or QST’s, and two, it’s a fabric waster which is really not okay. There is a silver lining though (see, I can find one in this morass!): when you trim the HST’s or QST’s down to size, you’re trimming away the “dog ears” at the same time, so that’s a bonus.
Some patterns these days may just tell you to do that from the beginning, cut large and trim to the right size after piecing, but I’m basing all this on my personal experience with patterns and books, which is probably old since I don’t generally buy patterns or make quilts out of books anymore, preferring to tumble over the cliff of my own creativity into the scrappy mess of UFO’s and failed fabric experiments at the bottom. When I was buying books and patterns a few years ago, patterns were written based on cutting the “exact” size you need, and expecting the HST’s and QST’s to be the right size in the end and they never were, and the edges were curvy and wonky in the bargain.
So what’s your solution to the HST and QST finished size/cutting size quandary? Do you have these issues with patterns these days? Do you cut bigger and trim, or just deal with the fallout on the fly when piecing blocks?
Edit: Crazy Accuracy Freak Girl wrote this while I was having breakfast. 😉 I try to keep her penned up and away from the blog, but sometimes she sneaks out and adds her two cents…or two dollars, as the case may be. Thanks for putting up with her.—Nadine