Cutting Tips

well, felwyn, i measure from the left hand side of the ruler. that is to say, i trim the left side of the selvage from the fabric i'm using to make it even, then use the same side to put my measurement on, cutting on the right hand side of the ruler edge. it seems to come out more accurate for me. some people cut the right hand side of the selvage and move the ruler. i find this shifts the fabric too much and mistakes happen.

JMO amy in CNY

I would be willing to bet the it has more to do with your sewing than with your cutting. If your seams measure an exact 1/4" you have to remember that when you press that seam to one side that it takes up just a tiny little itty bit of fabric to make that turn under. It may seem negligeble but as you said it adds up. try sewing a scant 1/4" and once that turn is made for pressing it should be pretty darn close to bang on.

Be certain that you are holding the blade of the cutter exactly perpendicular to the ruler and not at an angle. Be certain you are standing directly over the ruler and not looking from one side or the other- squinting- or closing- one eye as you line up the ruler can make a difference, too And make sure the blade is snug in the cutter but still rolls freely- snug down the nut and then run it along your mat with light pressure to make sure it is turning then adjust as necessary.

But my first impulse was to say to adjust your seam allowance. For machine piecing your seam allowance should be a thread or two less than a true 1/4 in.- the so-called scant 1/4 in. Your stitch length and tension adjustments can make a difference in how much fabric your stitching 'eats up' into the seam allowance as well. Check how you press- pressing to one side can take up a tiny pleat in the fabric- pressing seams open usually doesn't do this, but it is possible to create a tiny pleat on *both* sides with pressing it open!

The fact that you are so very consistent in the amount you are off tells me you are doing everything right, so I'd blame the seam allowance. Congrats on the consistency- that's a biggie! If you were all over the place or only short in one direction there are a lot of different possibilities, but this will be much easier to correct!

Leslie & The Furbabies in MO.

You want the line on the ruler that you're measuring from lined up with the edge of the fabric, but the ruler line should be ON the fabric, not along the edge off the fabric. But, no further onto the fabric than the width of the line. Hope that makes sense. I was taught this at some class someplace and it works! If you consistently have the ruler line to the side of the fabric instead of ON the fabric it does make a difference. Also, as someone else said, be sure your blade is perpendicular to the edge of the ruler and not slanted in. Just having the ruler line off the fabric and having the blade slanted could make a 1/16th inch difference. The thickness of your thread can also make a difference which I never thought of until I read it someplace in piecing tips.

Donna in SW Idaho

Following on from what Donna said: have you thought of measuring the width of the lines on your ruler? Some rulers (and they vary enormously) have very thick lines - I bought a Nancy Crow one once and the lines were almost 1mm thick! So, you have to take each of your rulers (if you have more than one) and measure with an ordinary geometrical ruler to see just where your line has to be placed to give you the exact width you want. It doesn't take long, but is infinitely worth it. . In message , felwyn writes

You have all given me many points to consider. I think being certain the cutter is perpendicular is a big one. Making sure the ruler is on the cut edge, even a thread away is a good point too.

Felwyn, I'm another who suspects your seam allowance of being just a trifle off, rather than your cutting technique. As Leslie said, you are so consistent that it should be a simple matter to figure out how to adjust. Here's how I was taught to check my seam allowance:

Cut three strips of fabric at 3" x 1.5". Sew the three strips together along the 3" sides, pressing each seam, so that you now have one pieced "block". Now measure your block. It should measure exactly 3" square.

If it's a hair too small, you know that your 1/4" seam allowance is a trifle too wide. That's where we get the "scant 1/4" seam allowance" you'll hear about so often. We all have to adjust for the thickness of the seam itself in order to create precise blocks.

HTH! :)

I will try that, thanks. It's a good way to see where the problem might be. Actually adjusting the seam allowance to a scant 1/4 in. is probably the easiest way to correct the problem, and it might not be the cutting at all.

Another thing I should have mentioned - if you start out cutting with one brand of ruler, don't switch rulers in mid-stream (project)! I stick to Omnigrid rulers exclusively because I know they are all the same. Compare them to others and you'll see a difference, sometimes slight, sometimes not so slight.

Donna in SW Idaho

Nah, once you get the hang of 'scant' you won't need to continually test. And please do consider Patti's very good advice and measure your rulers. I have one here that is reserved for whacking naughty gators and cleaning under the refrigerator; it certainly is no good for cutting. The absolute worst are the free yardsticks that may or may not be anywhere close, and a tape measure that has stretched just any at all. If I'm going to get crazy about accuracy, my favorite is a very long metal ruler from DH's shop. That fine tool will let you play with the 64ths. Polly

"felwyn" I will try that, thanks. It's a good way to see where the problem might

Actually, if your seam allowance measure an exact quarter inch, they are probably a thread too large. A tiny amount is taken up when the seam allowance is pressed, the fold of the fabric is about a thread or two, so your blocks end up being a tiny bit off. To test, cut 3 strips of scrap fabric about 6 inches long and exactly one and a half inches wide. Sew together the long edges so you have a "3-rail" block. Press seams in one direction. Measure the center. It should measure exactly 1". Just for fun, press both seams to the center strip and remeasure, then press them both away from the center and check the measurement again. You may be surprised. The "thickness" of the fabric and the diameter of the thread all play a part in this.

Pati, > Does anyone have any rotary cutting tips? My finished blocks are always a

Oops! My math was a bit off. Your finished block should measure 3" (length) x 3.5" (width), since you haven't yet used the seam allowances on the outside. Sorry!

This makes my heart smile and sing, Pati! . In message , Pati C. writes

Do you use the measurement on the cutting mat instead of the ruler. I find the ruler is acurate and not the mat.

Right Polly, I carry a 10" or 12" metal tape measure with my sewing kit, it is accurate. Those cloth tapes that are pushed on us ladies stretch and are not accurate, yes you can measure your waist with a metal tape. Another tip for accuracy, never measure from the very end of a ruler, for example, when measuring 12" measure from the 1" mark to the 13" mark, ends of rulers get banged up. If you look at a draftsman's scale you will see that the measurements don't start at the end of the scale for that very reason. Our rotary cutting rulers don't get banged up on the edges because we are very careful with them, right? Bonnie, in Middletown, VA

Great advice from everyone, thanks! I use Omnigrid rulers, and sometimes resort to my husband's very heavy t-square for cutting, it never shifts. I almost ignore the grid on the cutting board, it doesn't seem that accurate to me. I think from what all you have been saying, that the seams and pressing are the culprit, need to adjust for that. When there are many pieces in the block, the problem really multiplies. . . .

I'm going to experiment, and practice new tricks and techniques. felwyn

I try to place the ruler so the fabric edge I'm measuring from falls right in the middle of the ruler line. Rulers differ, so check yours to see exactly where the measurement is correct.

Another problem might be the way you hold the cutter. It should be perfectly perpendicular to the mat. If you tend to angle in, that might account for a thread or 2 of inaccuracy. Also dulls the blades quicker. Roberta in D

Thank you....

Pati, > This makes my heart smile and sing, Pati!

That was my first reaction when I read the note too.