Triangles Baffle Me
 

I'm currently wishing I'd paid more attention in Geometry class in high school... :hunf:
I can't figure out where I went wrong in the math on a design I attempted to create... I either did the math wrong or I cut incorrectly. This is the first time I've worked with triangles, and because they're kind of bordering a strip, I cut them with the straight grain (is that the right terminology?) on the diagonal and the bias on the other two sides.

Would someone give me some feedback on why this block isn't working? It's either bad cutting/measuring, bad seams (I think I'm doing good on straight 1/4" seams...), or a bad plan to start with. I'm making 3 of these, so if I fix it now, the other two kid's quilts will go easier.
https://www.quiltingboard.com/member...964-591778.png

Here's what the overall plan is:
https://www.quiltingboard.com/member...964-591233.jpg

I, too, have a triangle phobia. Lately, I've been participating in a block lotto.

You make 1 to 3 blocks from the pattern of the month. You send it in and each block you send give you a chance to win all the blocks of the month. The value is that all the ladies who post there are helpful and will help you if you get stuck making the block. Most of the posters have been posting there for years. You learn a lot and only have to make between 1 and 3 blocks, not a whole quilt. It seems as if all the chosen patterns have triangles.

I only participated a couple of times last year. I decided to do this each month this year to improve my skills. The ladies are wonderful and helpful.

bkay

I use this method. Always get perfect HST. I bookmarked it and downloaded to my "tutorial charts" file on my computer.

http://blocloc.com/wp-content/upload...rt-for-HST.pdf

I switched from using thangles paper piecing or just plain cutting 2 squares RST and cutting them diagonally in half per the formula for making HST's. [I added 1 inch to the size of HST needed so I had to trim up the HST's.]
I now use The Folded Corner Clipper ruler. MY HST'S come out perfect with no trimming. It is good for up to 5".
Eventually I'll experiment with larger rulers and the add a quarter ruler but trim either with this ruler of with the Fons & Porter trimmer ruler.

I thought the photo worked this time... Let me try again. [ATTACH=CONFIG]591781[/ATTACH]

The HST link looks like a great way to do HSTs! But I'm struggling with the set-in triangles, especially since (assuming pictures work this time and you can see what I'm talking about), my 'blocks' are set at an angle, so the solid colors make me think of a braid. [ATTACH=CONFIG]591782[/ATTACH]

I do appreciate all the help! You ladies/guys are awesome!

On point settings can be challenging, even when you have done them before. But you have done very well so far in figuring out what sizes to cut. Assuming those are unfinished sizes, so your block size is 6” square finished, you have the theoretically correct size setting triangles cut. And you cut them the correct way—to have the straight grain of the fabric on the outside. So that is all good.

So...what is going wrong? The blocks in the runner may not be coming out at 6.5” unfinished. Did you square them up before you put them together?

Those pesky double diagonal cuts can be harder than they seem. If you measure one of the short sides, it should be a tiny bit over 6 7/8”. The dog ears extend past the edge of the block to which you are attaching the triangle, and your seam, if perfect which mine never are, intersects right at the raw edge.

Mine never do. I just start with slightly bigger triangles, like 10”, slice them twice diagonally, attach them, and trim the edge to make sure there is a 1/4” seam allowance past the points.

The four corner triangles are cut from 5 1/8” triangles sliced once diagonally; I would probably use 5 1/4”. Again, you can always trim later.

You are on the right track making quarter square triangles to sew on either end of your square blocks to make your braid columns. That way the long ends of your triangles will be stable on the long edges of your columns that you will sew together to make the ribbon columns for the quilt. You can make the square that you cut for the quarter square triangles a little oversize by cutting a 10 inch square two times diagonally to give you a little extra wiggle room and trim the triangles after you sew them to the pieced square blocks. Instead of 9.75 use 10 inches. Good luck!

Look on quiltville.com. Bonnie Hunter has a chart with dimensions to cut setting triangles

Bonnie Hunter has great info on setting triangles. She provides the math and a chart:
https://quiltville.com/onpointmath.shtml

This is why I love my EZ angle ruler. If you need the setting trangle to line up with a block that is 6.5" unfinished, you cut a strip at 6.5" wide. Then you use the angle to subcut it. Since it has the "dog ear" at the top already gone, you're cutting a larger HST than you'd get if you went point to point.

Yes, doing this way you will end up with the bias on the outer edge, but to date, that has never caused me a bit of problems.