There is a quick easy solution to the veering off. Put your index finger of your left hand against the left edge of the machine foot while sewing the seam or coming to the end, just a light touch and your seam will not veer. I do this automatically now.

The easiest way for me to make fast, consistent, accurate 1/4" seams is to use an adhesive physical barrier, not a quarter-inch foot. I like these Dritz strips the best: http://www.amazon.com/gp/product/B0085L2Y2I/ and have found them on the quilting notions wall at JoAnn's but, if they are not available, I cut my own strips out of mole skin (found in the foot section of any drugstore) and pile the moleskin two-high. When sewing, I simply butt the fabric up to the adhesive guide. I can sew very fast this way and still maintain accuracy. One of the reasons I think this method is superior to a quarter-inch foot with a guide is that the adhesive guide can extend a couple of inches in front of the presser foot (which helps a lot to keep the fabric lined up properly) and also can extend a little behind the foot.

Be sure you understand the "scant" quarter-inch that most of us use for piecing. Even the Dritz ruler (red ruler sold with the adhesive strips) that is supposed to be used to position the adhesive guide is wrong; I measured it, and it creates a full 1/4" seam (too big for quilters). A good way to test your seam is to sew three 2.5" strips together, iron, then measure. If the seams are an accurate scant 1/4", the width of the strips will measure exactly 6.5". If it measures less, the seam is too wide.

I agree with this. If you are loosing the seam at the end of the sewing then your fabric is wondering and it is an easy fix. By either doing the above or getting a chop stick to or some pointy thing to hold your fabric at the end so the feed dogs don't pull the fabric away from whatever guide you are using. Just a light touch to keep the fabric pushed close to the guide is enough to solve this problem. And SLOW DOWN!:D

Let us know if it works!
peace

It is, maybe your needle is not centered to make the stitch equal a quarter inch seam? On one of my machines, I gave to remember to reset that needle hen I turn it. On as default is not what I want.......as far as the tail ends veering off, buy a stiletto or buy shishkabob sticks, cut in half and use the pointed end as a stiletto...better than metal stiletto --- if needle hits wood not as damaging as metal..by holding the edge as it is sewed it will keep it straight. Also, slow down your speed, maybe you are racing, slow and easy is more accurate.

Good idea, must try that, thanks Bella

Fabric and thread affect your 1/4" measurement. If you use thicker or thinner thread, different fabric, like homespun or flannel, this all affects your measurement. If you get a 1/4" foot and it makes the perfect seam for you without having to move the needle, you lucked out! Normally, you also have to adjust your needle position.
I usually use the same weight fabric and the same weight thread for all my projects but if I change something, I recheck my seam and move the needle if necessary. Here's a good tutorial on checking your seam:
http://www.quiltingboard.com/tutoria...ce-t89997.html

I also use a stiletto to guide the seam at the end.

It might be where you needle sits. I have one machine that every time I turn her off, it automatically goes to some weird setting all on its own and I have to play with the (Curvy) to get the needle exactly 1/4" from the little metal bar on the foot of my 1/4"quilting foot. I have a piece of cardboard 3" by 6" that I have one marked the one side exactly 1/4" and every time I sit down at that machine, I put the cardboard with the 1/4' measure next to the foot bar and gently lower the needle to make sure it is exactly at the 1/4" mark, if it does not, I gently click the button that moves the needle till it is exactly 1/4" and also, make sure that I hold the fabric gently so that it maintains its 1/4" all the way past the needle. That works for me, hope it helps

Yes, every machine is different as Rodney said.
I struggled with the 1/4 inch for years. I finally wrote down where I had to put the needle to get a 1/4 inch. Then I finally got better at my "art" and realized that it all wasn't me. My machine was finally sent back to the factory for and "overhaul." I got new feed dogs, new needle threader, you-name-it, I got it new. Can't tell you what a difference it made.
If you think you are crazy for not being able to get the 1/4 inch (and in my case a straight line; mine was straight but diagonal), consider that it just may be your machine.

It is a manufactured product with 10000' s stamped out. It is like any product. It must be checked to be sure. Don't assume it is accurate.

On my brother I finally put out for a 1/4 inch foot. It works when I pay attention. When I get a bit lazy it doesn't. Why? you have to push the fabric slightly up against the foot, if you don't it slips away a bit then you get a line that veers or you get too far off the foot you have a lot of trimming. if you push too hard it goes UNDER the foot then you once again do not have a quarter inch and your short. so I use nothing faster than the medium speed, and usually not quiet that fast, and watch what I am doing. Watching sure is easier than ripping a seam or going back and fixing a seam that goes off on its own path. I tried tape not enough but I think maybe tape AND a 1/4 inch foot are not a bad idea at all. that area in front would be lovely to have the fabric simply coming in at that angle and in line. going to go check out bonnie hunters trick.. worth a look for sure. I spent all of last year struggling with my 1/4 seam now is a non issue. ALSO: you can cut your block pieces out a bit larger sew them to the next piece and trim to size perfectly a bit of an extra effort, and a bit more fabric wasted but not much in the large picture. you do get even blocks then with correct seams so you don't lose all the points when sewn together.