I have been using a rotary cutter and mat for 15-20 years without any training. I recently took my first machine piecing class, and one of the first things we learned was to turn over the mat so the grids can't be seen, so it's taken some getting used to, but that's how I've been doing it for the last few months.

all the time...that`s how i learned it

I was taught to use the lines on the mat and ruler, but I am more accurate when I only use the lines on the ruler. I think "the right way" is whatever way gets you the best result.

I only use the mat lines when I cut large pieces like 18" x 28"

I know it is probably slightly less accurate, but I do use the lines on my mat as well as the ones on my ruler.

I do if I have the rulers from the same manufacturer as the mat. I have noticed that if I do, the cuts are more accurate. I have some rulers from a different manufacturer than the mat, so I am careful to use only the 'correct' rulers when I'm cutting things that are critical to get exact.

I always line my ruler with my mat lines, top, bottom and side.

I line up my fabric to be straight along the grid lines of my mat but I use the ruler to imeasure the width before I cut along it.

PS I always use the same mat and ruler for cutting out each project as they all differ somewhat.

I always cut fabric,using mat lines and ruler lines. It works for me. After cutting several strips using only ruler, sometimes the fabric is no longer straight.

Ditto - and they are especially useful when making patchwork jackets and clothing.

I alwaysw use them when I cut strips and then squares and sew half triangles. I make sure the mat and rulers are the same company.

I always use the same mat and ruler to keep measuring consistent

When the first mats came out, they didn't have the lines, so that is how I started cutting, and how I still cut. I was told that the lines on the board aren't 100% accurate.

I have never used the lines on my mat.

I always do it that way, possibly because I am self taught? I was reading some older threads earlier today (when I should have been working <g>) and I saw that lots of folks hee don't use the lines on the mat at all. Not sure how they do that.

The issue of accuracy aside, my main objection to teaching someone how to cut using the lines is one of fundamentals.
If you are in a situation where you don't have a mat with lines
(workshop, class, retreat, at a friend's, etc.) can you cut without the lines? I have a friend who can't, and sometimes it's a problem when we get together and she has to use a mat without lines...she just can't do it. But then, I'm a dinosaur and I think beginners should at least have a rudimentary knowledge of drafting patterns and making templates. Okay, you can get your guns out to shoot me...

I agree with crashnquilt. You can use one or the other but not both. Same with sewing machines.

That's my way of cutting too.

I use the lines on the mat and have had no problems, thought that was what they were for.

You can butt two rulers up against each other. Say, you need a 16&1/2" square to cut in quarters for setting triangles. Use the 12&1/2" ruler combined with (butted up against) a 6" ruler. With the even edge of the fabric to your left, lay the 6" ruler so that 2" is to the left of the cut edge and 4" is to the right (as if you were going to cut a 4" strip) then butt the 12&1/2" ruler up against the 6" ruler. So now you have 4" + 12&1/2" or 16&1/2". Make your cut against the right hand side of the bigger ruler. Is this clear as mud? utt

I do use the lines on the mat all the time.

I just use the bottom line to make sure the fabric is even, and i use the side lines to gauge how straight i am holding the ruler

I use the two rulers, also, and love to just use my ruler to line up the fabric for a cut.

I use the mat lines when I true up a fabric, but rely only on the lines of my rulers when actually cutting.

This is how I was shown to cut fabric too - now I'm looking to buy a little bit larger cutting mat. So yes, I use my mat all the time for cutting with the rotary cutter.

I always do it that way, lining up the ruler with the mat. It is the easiest way for me.

i use the mat but if i do that i dont combine it with any other way of measuring, either mat or ruler all the way never both i heard the two could be differant

Before I read the other posts I will put in my 2 cents :lol:
Only when I don't have a large enough ruler, not very oftern and not if I don't have to.

I do on rare occasions. I was told mats aren't always true

I do use the lines on the mat and on the ruler. :D

matt lines aligned with the ruler lines to cut
how else can one be on the LINE and straight?

I use the vertical lines on the cutting mat if I'm cutting strips. I use an O-lip-fa ruler that firmly hits the bottom edge of the mat to stay straight, and I make sure the lines on the ruler match up with lines on the mat. I usually have to move the fabric slightly to keep the edge right on the line before my next cut. If I'm cutting or trimming small squares, I prefer to use a square grid ruler so that I can easily line up a horizontal and vertical edge at the same time, and in that case, I ignore the lines on the mat.

I use the lines on my mat just as guidelines...I trust my rulers a lot more!

I do often enough to say I do. I think you get a more accurate cut that way, but sometimes I don't have to use the cutting mat's lines.

I, too, use both methods at times, but mats are not always accurate, so I teach my students to use a ruler and not rely on the mat markings. Also be aware that you CAN indeed use a ruler when the cut is wider that your ruler...just put 2 rulers side-by-side! I do that all the time for wide borders, especially if your mat is well worn or not terribly accurate.

I do both!

I never used to use the lines on my cutting mat; always thought the rulers were more precise. Until I made my bow tucks bag, then it dawned on me "why and I struggling so hard with this" butting up one ruler to another to get the width/length I needed. Now I use the lines in conjunction with my rulers but use the rulers more than the mat. :-)

I do this all the time.

exactly what she said. They don't always match and it doesn't make a difference which one you use as long as it's the same through out your project.