Dealing with the elusive 1/4" seam...
 

I'm relatively new to quilting (and sewing for that matter). I enjoy the process of designing, cutting, piecing etc, but I have a dickens of a time keeping things matched up as my blocks grow. I am certain that most of my problems have to do with my inconsistent 1/4 seams. I've bought and tried various 1/4" presser feet, used diagonal seam tape, tried the magnetic guides etc, and still haven't zeroed in on the "perfect" seam allowance.

I'm sure I just need tons more practice to get it right, but in the meantime I am dealing with blocks that are less than perfect. I've recently read https://www.kimberlyeinmo.com/the-el...-and-conquered and sounds like maybe I should shoot for the scant 1/4" instead of the perfect 1/4".

I do my HSTs by the 2-at-a-time method (over-sized), then use a ruler to cut them to the exact size. Maybe I should make everthing oversized and cut to size? What tricks can I use to make my 12.5" blocks be 12.5" blocks when I'm done?

Good day to you! I had some problems with my 1/4 inch seam allowance and like you tried all the same tricks. I finally had an aha moment and realized that my 1/4 inch seam became wonky at the end of the seam and when going over seams putting blocks together. My machine is a zig zag, decorative stitch, and embroidery model. When I put a 1/4 inch foot on it, the foot would only cover the left feed dog and did not cover the right feed dog. I put my straight stitch foot back on (the one that covers both feed dogs), moved my needle to the right, and fixed the wonky seam problem. Hope this helps.

Yes, I discovered the feed dog problem when I put a 1/4" foot on mine (I tried several different ones). Unfortunately, I have an older machine that doesn't allow me to adjust my needle side-to-side. So far, I've found the diagonal seam tape with my regular zigzag foot gives the most consistent result for me. But my blocks still come out too small.

If you measure the seam allowance and it seems ok, maybe you're not pressing correctly. That can affect the size of the block. Are your seams lying nice and flat?

hugs,
charlotte

If your unit is ending up the size you want it to be, that is what matters.

Fabric prep before cutting is another discussion. Some unwashed fabrics will shrink when being steam pressed.

Back to seam allowances..

Try cutting four strips of fabric 8.5 x 2.5 inches.

Sew the strips together using "your" 0.25 inch seam allowance.

Press the unit however you prefer. Pressing seams to the side or pressing them open is another discussion

Now measure the size of what you have.

If it ends up being 8.5 x 8.5 - your seam allowance is "perfect"

If it ends up being 8.5 x 8.75 - uou need to make your seam allowances deeper/wider

If you end up with it being 8.5 x 8.25- then you need to made the seam allowance narrower/ shallower.

This testing/practice is a bit of a bother, but can minimize frustration down the road.

Where variations can occur besides the seam allowance width:

Some threads take up more space

A heftier fabric takes up more space where the fabric turns at the seams

overly entusiastic ironing/pressing can distort the piece

Even measure the actual size of your cut pieces!

"My" 2.5 x 8.5 piece is actually a tiny bit larger than 2.5 x 8.5 inches because of the small space between the ruler and rotary cutter and how I place my ruler.

The more pieces involved, the more chances for differences to accumulate

I have taken index cards with 0.25 line ( or graph paper with quarter inch grids) and sewn on that to figure out where to line up the presser foot with the edge of the fabric.

It might be helpful when cutting to keep the ruler line inside the fabric rather than outside. Sometimes that gives you that tiny bit extra.
Hope that makes sense from my pre-coffee brain!

Another thing to consider is that some of the newer modern machines with very wide feed dogs can mean the fabric is only going over one of them which can make things wonky. Some machines don't have a changeable stitch plate or a way to adjust the needle to the left or right. Agree with the method bearisgray posted about measuring the finished piece. May have to make practice piece for each project if the fabric/thread combo is different. If I am making something with no points and perfect accuracy won't affect the finished project, I just roll with "close enough", and make sure everything is the same amount of "close enough". A nine patch or similar for example is very forgiving.

Most of us have had to go through a learning curve for what works with our machine(s).

A reminder - if you change your machine or use a different ruler - and you are in the middle of a project - to verify that things are matching up to the previous work.

The current project I'm working on uses blocks of 9.5" x 9.5" ((churn-dash). On the square units (HSTs and half-squares), I'm pressing seams open and I think they are lying nice and flat. I tried a couple of blocks pressing the row seams to the side, but I think I prefer pressing open.

The blocks end up being about 9.25" and the edges are not quite even. Great suggestions bearisgray! I will try those.

I'm pretty confident that my cuts are acurate, And since my HSTs are cut to 3.5 x 3.5 after sewing (and my center block is 3.5 x 3.5), I suspect I'm off on my half-squares The suggestion on the strips will probably help me. I might try a narrow seam on those and then cut them to size.

1/64 of an inch seam allowance variation may not seem like much - but on 8 seams that is 16/64 - 1/ 4 inch variation.

If all the units are the same size squares - the finished product might be smaller or larger than expected - but will go together without many problems.

if all your blocks are the same size - and the same block - you can probably " safely" proceed. But if you are using sashings , they would need to be adjusted for length.

and NEVER switch machines midproject. Ask me how I know.

Ha, I solved my problem with trying to get a great seam on my higher end wide feed dog does fancy stitches and embroidery machine....by...wait for it...getting a lower end smaller 5mm narrower feed dog machine! Love it, no more fiddling trying to figure it out with the wide feeddog machine. And as a bonus, my smaller machine is easier to take to retreats and classes where I don't need all the features on my other machine. A straight stitch machine would work as well and that could also work for a free motion machine too. I still love my does everything machine but it is a pain for piecing. So, my smaller machine sits in my cabinet for piecing and the larger machine can go in the cabinet if needed but....it sits on top of the cabinet anyway when I am doing embroidery. Win, win.

Another work-around is to make the blocks a little bit bigger than you want and trim them down. It adds steps but gives you wiggle room, which I need, myself.

And use a clapper. They're easy to make. If you don't have one, put a cloth on top of one of your blocks after pressing and put a heavy book on top. It can make a huge difference. (real clappers are better if you're going to add them to your process.)

My clappers are made with scrap wood and are adjustable in terms of weight (using ankle weights.)
hugs,
charlotte

I sold my first, very expensive, sewing machine because the feed dogs would always grab the fabric at the end of the seam and cause wobbles. I noticed in classes that Bernina machines and Juki machines did not do that, and switched my machine!!

Past that a consistent 1/4" seam is a product of practice. If you want to do accurate piecing and have your intersections and points come out perfectly, you must master accurate seam width.

Note that you must also be cutting accurately. If your pieces are not cut accurately, you are not going to be able to save the block with 1/4" seams!

That said, fabric is forgiving, and you can pin it into submission if you are close to the 1/4" seam. Use Clover Extra Fine pins to make intersections meet.

I hate the term "scant 1/4"...because what is THAT??!! Use the edge of your 1/4" foot but be sure your needle is indeed positioned 1/4" from the side of the foot.

If you practice a simple Ohio Star quilt block, photo below, and master getting those seams consistent and matching, you will have mastered 99% of quilting blocks!

https://sewcanshe.com/how-to-make-an...step-tutorial/

To keep your seam from veering at the end, put your left index finger on the side of the foot as it finishes sewing. Your seam will stay straight. I use a Juki straight stitch machine for piecing. I have an older machine that has the decorative stitches that I seldom if ever use. Juki has two 1/4 feet one is for a scant 1/4" and one has a guide for a full 1/4". Another thing to check on your machine. Most line markings on the face plate are measured in metric from the center of the needle hole. Even if it has the 1/4 and so forth markings. Measure the seam from the needle before trusting the marked line.

As bearisgray wrote, you want to focus on what size your units are ending up. There are two possible causes of problems: cutting that is slightly off, or seams that are slightly off. (A person can have problems with one or both.) I suspect a lot of starting quilters have problems with being slightly off in their cutting, and one piece of evidence that supports my theory is that many people who switch to cutting out their pieces with dies (such as by the Go! Fabric Cutter) report that their piecing becomes more accurate. It is very important to get the measuring line of your ruler *all* the way onto the fabric, not next to the edge or part way on.

bearisgray wrote a good test to do with sewing four strips together. I highly recommend doing that test and then pay particular attention to the width of inner two strips. Each of them should be exactly two inches wide, the whole length of the strip. If they are not, either your cutting or seam width needs adjusting. If you've *thoroughly* checked, your cutting results, then you can work on fine tuning your seam width.

For avoiding problems with the tendency of many machines to want to swerve at the end of seams, I have found using a walking foot to be very helpful.

Thank you all for the suggestions. I had some strips cut for double sashing that I hadn't yet sewn together and used those as a quick test (part of the current projejct so not four wide like suggested). I double checked the cut measurement and they were right on. However, after sewing and pressing (seams open), I lost about 1/16 inch. So i need to adjust my 1/4" marks and try again. At least I know where to look.

I'm almost done with this project (place mats and table runner), so before my next project (full size quilt), I will do more extensive testing and practice.

(Salsa Table set design below)

I've been quilting for 10+ years and that 1/4" is one of my biggest problems. I always overcut - I have to, if I don't many of my blocks will be under size (and many will be oversize). I also dislike the "scant" 1/4". My feeling about that is that if they want us to stitch a seam a scant 1/4" they should make a presser foot that measures a scant 1/4". One thing that I recently discovered and that has helped is that my machine has an adjustable needle. I can move it a tiny bit to the left or right. If I adjust it to the right spot and use my 1/4" foot I end up with seams that are a scant 1/4". So if you haven't yet, check to see if your machine has this feature. I've had my machine for 10 years and can't believe I never knew this existed until a couple of months ago.

My machine doesn't have that feature (unfortunately). It is a recently-resuscitated, 70's Montgomery Wards machine that sews like a dream. It is a real work horse and I love it, but am still learning how to get the best 1/4 seam for piecing. (I think I'm zeroing in on it.)

On the other hand, I am learning how to "square-up" stuff as I go - which is valuable in itself. Below is an example of how far off i've been (the block should have been 9.5" - like the pieces I'm trimming).

I've always maintained that sewing is a physical activity, maybe small muscle but still there is hand/eye coordination and other things at play. You can't just get up and play professional sports, and (most of us!) can't do professional sewing results unless we practice practice practice. I just took about 18 months off after daily sewing for years, and it has taken me some time to get back to where I want to be. When I first switched from garment construction to quilting, the 1/4" seam seemed so impossibly small... but after time it starts seeming rather large and accommodating and you can tell if you are right on or big or small.

You said you've tried some of the seam guides, what I had on my vintage machine was an adhesive bandage, several inches from the needle near the edge. I took a piece of graph paper and put the needle through it and used that for placing the bandage. The visible guide of the plastic helped, as did the little hump of fabric. Nowadays I'm a big fan of the 1/4" foot and use it many ways.

It didn't occur to me for years (decades even) to square up my sub-units, I'd just fit them in as they were. When I decided to start checking them anyway, I slowly made the shift away from trying to be very precise with my cutting and my sewing to doing the cut large and trim down. Might as well make it worth my time to check by doing some trims, and it is happier and easier for me not so tense. While trimming can be boring and it feels like it takes a lot of time, I feel it evens out in the next step, no fitting in just nice straight cuts to deal with. If it is just a couple of threads I don't bother but often there is more, especially since I tend to sew scant anyway.

For those that know me, I was not very appreciative of what I originally called "fabric wasteful techniques" but I did a few tests and found that I really don't waste much fabric. Typically whatever I was cutting had a couple inches left from the row that now accommodates the slightly larger pieces. Even on very busy queen sized quilts, I don't think I've ever needed more than one extra row of fabric.

Any time you are doing modern strip piecing techniques or trimming down, you should use a rather small stitch, at least 12 per inch. I think I'm usually in the 16 range -- it makes it really hard with my vision issues to take out stitches so I still try and be precise but know I can be a speed demon when I want to be.

Sadly there is no one "right" way to cut large, we each have our own techniques. Square units are easy for most of us. Pieced triangles are often easiest to have one cut as normal and others cut larger. To help with the trimming I use tape to mark the lines on my rulers. There are many brands of 1/4" tape and I always have a roll in my sewing kit.

I like to use presser feet that match what the seam size I want, by using presser feet with a guild or compensating presser feet.

I have been using presser feet with a seam guild on them and have a good selection of different seam widths for both the left and right sides, depending on which way I am sewing the seam. I recently found that one of my sewing supply places Cutex Sewing Supplies, carries a set of 8 different sizes of compensating presser feet in a set, one set of 8 or right side and one set of 8 for the left side, for a good price and I liked the sizes.

I'm finding that I prefer the compensating presser feet better than those with the attached seam guide as it fits closer to the base of my sewing machine and it keeps the fabric from dipping under the 'guide' better. I like the different sizes for doing applique, edge sewing on my binding, and regular piecing of blocks. I don't have any problem with getting the seam size sewn that I want, no matter what width I'm using.

I also square up each process of piecing my blocks, and between the two, presser feet and squaring up, I don't have any issue with matching up my blocks, or losing points on design features.

I wonder if it's not the seam allowance, but pressing with steam. Is it possible that your fabric is shrinking?

Just a note about the set of 8 is for high shank machines. https://www.cutexsewingsupplies.com/...32221481828405
https://www.cutexsewingsupplies.com/...32221481697333

This is one of the reasons I love having a high shank machine. There are so many presser feet that you can find for the high shank machines, that aren't made or sold for the low shank, and/or clip-on presser feet machines. And others like the Bernina Machines, their presser feet are really neither high or low shank, so you have to get the Bernina brand if you buy presser feet.