The difference between a scant ¼" and a regular ¼" is only about a sixteenth of an inch and would not result in you losing a half inch off your unfinished block measurement. Test the width of your ¼" seams when you use your piecing foot. You could just need to adjust your needle position.

If I read your question correctly, you are looking for something that shows you how to sew an accurate 12½" unfinished block, is that correct? A book such a Malone's is simply a compilation of block designs, not a how-to book at all. There are many tutorials online on accurate seam allowances, try searching through some of those for help.

And stick with it...quilting IS fun and once you get the basics down pat, you'll have a ball!!

I often use the "It's OK if you sit on my Quilt" book because it has the blocks broken down into a grid pattern. For the 12" swaps I usually use the 6-patch blocks and double the size of each increment.

As for the 1/4" seam, I think it's important to KNOW where you need to align your fabrics with the foot to get a clean seam.

My favorite book is Carol Doaks "50 fabulous paper pieced stars". Its probably the only book I may actually wear out!

I have the Better Homes and Gardens book "501 Quilt Blocks" and I really love it.

But you have to make all your own templates from the block diagrams they show, so if that doesn't appeal to you, you might want to look for something else. I suggest going to your local library and trying out different books they have before buying one.

Thank you everyone for your advice.
I know that the problem is the way I'm sewing the blocks together, maybe even the cutting and pinning.
So, I'm slowing down and checking everything twice.
Ordered a few of your book suggestions from the library, to see which ones may be best for me.

Also if you have a Half-Price Books near you they often have some of the basic books.