I had this problem when I was overly focused on lining up my selvedges. Now when I make my first fold, I do not focus so much on the selvedges. After my second fold, I make sure that the second fold is the one that I line up on my cutting mat closest to me. Here are cutting directions from Quilt University. About half way down they talk about cutting strips. I hope this helps.

Here is a link that might be useful: Quilt University cutting tips

This is going to stand some of your hair on end. When I am working with lots of strips for anything, I don't cut them. I rip them. This is what separates better quality fabric from stuff you should shy away from working with. So many cheap fabrics do not have a "true" grain. The bolts are almost cut on a bias. This throws certain patterns off as well and is what makes tailored items look not quite right but you can't put your finger on it. We also know since dress patterns get specific about laying out the pieces in respect to grain lines, that if pieces aren't cut along a true grain, then they have more give or less in certain directions. The more seams and pieces, the more evident it is, because if you sew together a quilt with the grains of some pieces running on a bias, sooner or later, they'll stretch differently and the end product gets some poofiness or pucker to it, or needs blocked each time it's washed.

So.....I find the true grain line by doing a few rips and then start my measuring from the line the fabric wants to rip on. I just nip an half inch or so into the fabric after I mark the spot with a ruler and then rip. The edges when properly done do not ravel any faster than cut material, often less.

I take my length of fabric and hold it up by my fingertips with the selvedges at the top. I carefully move the to layers in opposite directions until the folded edge no longer 'wobbles' back & forth. Then I carefully lay it down & press it.

When I make my first cut to even up the edge, I carefully fold it open and see if that strip is straight. If not, I redo the above procedure. I line up my ruler with the fold before cutting.

Then as I cut a few strips I recheck the raw edge using the ruler on the fold and re-straighten the edge as needed.

Clear as mud?

I pretty much do what Jennifer in va does. However, if I'm cutting long wide strips for borders - I tear, and tear parallel to the selvege edge - strips are straight and true!

I've tried the tearing and was never happy with the results. I never fold more than once and my strips come out ok most of the time.

Vic

I think tearing distorts the edges of the fabric and makes them "tighter" than the center. And tearing on the unstable crosswise grain can especially stretch the edges out of whack.

Wobbly cutting is usually due to one or more of the following:
~a dull rotary blade
~the blade needs lubrication
~incorrect fabric fold
~the blade is not tightened enough
~not enough pressure on the ruler
~not enough pressure on the cutter
~not moving your hand along the ruler to follow the blade

Like all skills, it takes practice, and is a great use for some of the ugly fabric wasting space in your stash!

I've never had a problem but then I only fold once (what would be pretty close to the original fold, which doesn't show anymore after being washed and ironed) to cut...I think I do what Jennifer does by holding the fabric up along the selvages and letting it drape, wiggling it along until it hangs without any "folds".... and a real key is letting that (for me, left) hand that holds the ruler walk up the ruler to hold all steady...

think tearing distorts the edges of the fabric and makes them "tighter" than the center.

I think it surely can. When I do tear a strip, I whip it tight pulling at both ends at once and it usually flattens it nicely and all the weave looks even. Most all stitching does require at least an eighth or quarter inch seam allowance, and if there is any distortion at all, it's in that allowance. I absolutely agree with you that fabric should not be ripped cross grain. You can tell by the "feel" of it, that it's struggling.

You might want to look at a pic I put in the gallery where I posted a picture of my first quilt, a puff quilt........concerning how to use ugly material. I am LOL. How do we come on collecting ugly stuff? I have a lot of it as well. I use less perfect scraps, ugly scraps and scraps of stuff with minor stains or tears for rag rugs. Done with some care, and an eye for design in the braid, they can be attractive and also useful and thrifty. They take a lot less effort than a quilt, and if you are into crafting for $$ (I don't) sell well at shows. A vendor at our local farmer's market, who was certainly old enough to have been an adult during the depression made them and had a steady clientele.

I do both, tear and cut. I like to tear when the strips are sewen togeather. When I tear I press the strips before they are put togeather straightening them as I do. I agree the the grain is much more accurate that way. I have seen on evidence of distortion.
When I cut I follow the suggestions as to selvages tog. sliding until the fabric hangs straight, then I lay the selvage edges at the top, smooth to the fold and the bring the fold to the selvage edge (4 layers). The I slip the rule in the fold making sure all layers are smooth then I trim edge to be cut. I have had V's but only when I have failed to make sure everything had been smoothed out properly.\
Jayne

hmmm...now I know what I've been doing wrong!!