Seems funny that the lovely Pioneer ladies didn't have "scant" problems. Seems like it is a modern problem.

I have had the same problem and just couldn't win the battle. I finally pruchased the stripes that adhere to your machine I did test strips and when I got it right I stuck one on. The quilt I'm working on now is the first I've used them on and it is coming out better than any I've made so far. The plastic strip is kind of raised so you ride the fabric next to it. One of my problems was I didn't have the fabric running stright all the time. this helps with that also. Good luck!

The very first quilt I made, I marked every square and made lines. I have a table sewing machine. Now I use the pressure foot as a guide. I don't make quilts for shows. I of course had at the beginning of my quilt journey wanted to be PERFECT and got upset when my squares weren't lining up properly. Instead of enjoying the process, I was getting stressed. The wonderful quilters here gave me some very good advice.
If you can't see any mistakes while riding on a galloping horse, I would not be worried about it. Relax and enjoy yourself. That is not word for word, but, I did get the meaning and I am more relaxed and enjoy what I am doing

Wish I'd seen this before we worked together stiching a project together . 3 of us matched and one was different . Threw whole piece out. Not sure who was correct ,but next time will do tut first . Thanks

If your machine allows you to move the needle, move it until your seam is measured out to be a ¼" on whatever foot you want to use. I did-do this and works out perfectly.

Betty, I have a question for you. Is your machine set into a table top, or do you have to sew on the machine sitting on a table where the only flat surface is when your fabric comes across the bed of the machine? I can't sew anything straight unless my machine is dropped into a set in area.

I feel that as long as I am close (within a thread or so) of 1/4"...and I am using the exact same thread and machine throughout the quilt...I am fine. Yes, my finished quilt may be a bit larger/smaller than the pattern states...but it's my quilt and I'm fine with that.

Not all measuring tapes/rulers have the exact same marks...so if you are real close...like within a thread width..just keep that seam allowance consistant...that's the main goal...don't be right on for one block and a stitch width off for the next...that's where the trouble happens.
Actually...I stitch a bit smaller than 1/4" (made a red mark on my clear foot)...and when I have all the blocks done...I check the size and trim to equal the size needed or if there is more than 1/16" difference...I trim to the size of my smallest block...so all blocks are the same size.

One quilting teacher told me that sewing on the line created a 1/4" seam and sewing just to the outside on the right gives you a scant 1/4" seam. It works for me and hope this helps.

When I first started years a go my 1/4 was not a quarter in. They were ever so slightly off. It will make a difference if you want points to match properly. This was on my 100 brother sewing machine; although, it came with a quarter inch foot it was hard to keep the fabric guided in straight and even. Some of this behavior was learning to sew straight.

Then I up graded to a Singer quilting machine which had an adjustable needle position, big help with the quarter inch foot. The I saw this quarter inch foot with a guide. The guide with the moveable needle position greatly improved my accuracy!

I would recommend the investment in foot with the guide, it's worth it.

I took a 2-day class with Harriet Hargrave a while ago, and one of the things I learned changed how I quilt.... the goal is NOT so much to get 1/4" seam allowance as it is to get the right sized block! No one will ever see your seam allowance after the quilt is made. If you have to make your seam allowance a bit more or less to get the correct size finished block, then do it. I taught a class yesterday and put these tips on the board for students to try when making their 3-strip test patch (sew 3 strips of 1 1/2" wide fabric together, press and measure to see if center strip is exactly 1" wide):

1. Cut accurately, use tape to mark the line on your ruler if you are not confident with rulers yet. Use the lines on the ruler, not the grid lines on your mat for better accuracy. Creative Grids makes great non-slip rulers.
2. use a 1/4" piecing foot, making the seam a scant 1/4" by not shoving the fabric too far to the right
3. move the needle one tick to the left or right to help achieve the desired seam
3. use a single-hole throat plate
4. use Bottom Line or So Fine bobbin thread TOP and bobbin (50 or 60 wt. thread creates less bulk in the seam and is just as strong as heavier wt. thread according to Bob Purcell, owner of Superior Threads)
5. use a smaller needle such as #70/11
6. use thread catchers and chain-piece your assembly
7. press (not iron) your blocks, setting the seam first, and be very sure NOT to have an tiny pleats of fabric in your seam. Use a light spray of starch or Best Press
8. square-up carefully
9. when doing cross-sewing on pieced blocks where you are going to be sewing over seams, use your walking foot instead of 1/4" foot
10. always nest and pin seam intersections
11. once your accuracy improves a bit, make your stitch length 1.9 or 2.0 instead of the default. This prevents the end of seams from opening up as you work with a block.

I hope these tips work for you. Keep trying! Let us know how you do.