Question about size
 

I am doing a quilt off the Sunlight and Shadows ..It calls for squares cut 3 1/2 and 3 7/8 s..U then have to cut the 3 7/8's on the diagonal to mix 2 colors .Then u connect the smaller square to it..They then say u will have to trim the bigger one..Which u do on 2 sides..This messes u up in more than one way..Unless u really watch every thing...Why can't I just cut it smaller by 2/8's ..Which is what I usually have to cut off on 2 sides..I know it has to be larger to cut the diagonal..But I think ..If I cut it 3 7/7 or 3 6/8's ..Would that work?..There are many points and seams to this pattern .That have to be matched.And this extra can throw it off .. I could do the diagonal pieces then trim them to 3 1/2...But again this just makes more cutting and slows the sewing down...Thanks for any help

It sounds like they are having you make half square triangle units (HST's). When I make HST's, I cut them 1 inch larger than the finished size required instead of the 7/8" they are having you do. I then place 2 of those size different colors, right sides of fabric together. Draw a diagonal line, sew 1/4" on each side of that line. Then slice on the line to get 2 sub units of the different colors. After pressing, I trim them down to the proper finished size. Yes, this makes extra trimming/cutting, but it ends in more accurate units for me.

In theory, if you cut the 3 7/8" units accurately and sew them accurately you would have no need to trim. I'm not that accurate in either case, so I up size accordingly.

Check your directions to make sure these are the units they are actually having you make. I find it helps me to read through the entire set of directions first before tackling any cutting. You could also do a test with paper first if you have no extra/scrap fabric to make a test block.

for the HST - half square triangle units - made of two triangles - the general formula is to cut the squares 7/8 inches larger than the finished size of the unit.

If you want a 3 inch "finished size" unit made of HSTs - then you cut your square 3-7/8 inches.

Many people have learned to add ONE WHOLE INCH to the finished size - for a "finished size" 3 inch unit -to cut the squares four inches and then trim down. Most of us trim off about 1/32 of an inch.

You can try what you want to do and see what happens. Some of us have to TRY whatever to believe/trust the advice we have been given.

Exactly what they said.

Now ... when you trim the HST's down, make sure that you place the diagonal line of your ruler on the diagonal line of the HST where the two fabrics meet. I typically trim ALL FOUR sides of the HST.

I agree that this is the formula for making HST and I add 1" and trim. Before I trim however I sew 1/4" on both sides of the diagonal line. I don't see where you are making HST but it seems rather you are adding the cut triangle to the square. I'm also confused about your comment that you trim two sides. If you are making HST using the mentioned formula you trim 4 sides unless you have the Quilt in a Day ruler which you trim a folded HST on two sides.

A picture would really help of the quilt and the pieces in question. There are too many unknowns in your description to be able to answer. I'd like to help but I'm confused.

If this is the block that she is asking about:

http://www.quilterscache.com/S/Sunli...dowsBlock.html

It is made with squares and HST units.

The 7/8 measurement assumes that you will sew a perfect seam, so if you cut your squares at 3 7/8 you should not have to trim anything. The pattern says: "Trim to measure 3-1/2" if needed..." Cutting your starting squares at 4" will give you a bit of wiggle room, because often you will sew the seam too large and your square ends up smaller than 3 1/2. You can't trim it & make it bigger :). Most folks find it preferable to cut the starting squares at 4", then trim just a tiny bit. If you haven't cut your fabric yet, I would cut a pair at 3 7/8" & a pair at 4", make your HST and see which one you prefer.

Yes..Bearisgray that is the block..Thanks for the answers..I was just looking for a faster way of doing the block without the extra trimming.I guess if it is worth making it is worth the extra time ..It is for my Grdaughters wedding quilt..The colors are deep purple and turquoise with a muilt color print of both colors for the 3rd color ..The colors are not mine taste ..but I did find the perfect multi material to match and it is pretty..I have only a few blocks done so far..when finish I will post it..again thank u for the advise.

For me, it is well worth the extra time to trim so that it's perfect for assembly. Sometimes they aren't perfect otherwise (seam off, fabric stretchy, etc.) I'd cut them 4" and trim down. :)

When making HST's I also cut the squares an inch larger instead of 7/8, but there are several different ways of making HST's, so I would suggest Goggling various ways of making them.