I need advice on trimming a block with a 60* slope. Pics included to help!
 

Some of you may have seen the blocks I've made for the Back to Nature quilt. All was going well until block #6 which requires four two-part rectangle sections. Out of the 10 or so rulers I have, only one had that 60* line and it wasn't big enough, so I estimated and the block didn't come out perfectly--but acceptable. It's posted here: http://www.quiltingboard.com/picture...e-t174150.html

So--since there's another block coming up with the same section, I bought a ruler today--6 by 12--that has the 60* line. I cut some scraps out to play and practice. The directions say to keep rotating the block until it's the desired size and to keep that line through the middle. First rectangles were cut at 4.5 by 6.5 and once cut on the diagonal and sewn back are to be trimmed to 2.5 by 4.5! This is trickier than I thought and the one I did still isn't perfect. Good thing I'm practicing!

So--here are illustrations. Theses are cut the same size as the ones for that block. I can't believe how much is supposed to be trimmed off! But--you can see the piece isn't square to begin with, I guess since it's not 60* as it's made. But--for those who have done this sort of thing before--do you have any hints on how to trim it perfectly? This is the first time I'm been stumped in a long time! A learning curve!!

Karla, you have me stumped with all that math...I would suggest walking away from it and coming back with a fresh mind.
I was going to pay my quarterly sales tax today and the website and I are not seeing eye to eye...I've done it several times before, but not today. So, tomorrow is another day.

Oh but I have walked away--for several days to work on a ragged flannel--and this is my fresh start! LOL

I don't understand why you must have the 60 degree ruler since you have a rectangle that is cut in half diagonally. Seems that is the important part and not that it is 60 degrees.

They stress the 60* thing... really stress it.

When they are sewn together, you place the 60 degree line of your ruler on the stichline and make sure that you have 2.5 inches on top going to the right and the 60 degree line should be 4.5 inches down where it meets the stiching. (You forget about the squarness of the block. That's why they are so large in the first place. There has to be enough material for you to cut the 2.5x4.5, with the 60 degree angle on the stitching line. Then you turn it around and do the same thing again. It looks to me that's what you did. Just make sure you line it up perfectly and you are good to go. Happy quilting!

Especially since that lower right corner on the ruler does NOT fit right at the corner of the block because of the way the 60* line is drawn on the ruler.
A 60* line will work IF the 60* line goes right to the point of the corner of the ruler so that you can cut straight up the side of the block you've sewn.
The Olipfa 12.5" square ruler has such markings. Shown here in example, both 60° lines are on the ruler and 1 is placed on the block's diagonal seam.

Jan in VA

A rectangle measuring 2.5 x 4.5 won't give you a 60º diagonal...ever. The side measurements of a 30-60-90 triangle are always in the ratio of 1:√3:2 (iow, side opposite 30º is 1, 60º is √3, 90º is 2). Your rectangle would have to be either 2.5 x 4.3 or 2.6 x 4.5.

ditto ^^^^^:thumbup:

Added thoughts that might, or might not, help you. It would seem to me that the finished HRT size is more important than the angle since you have to choose one over the other. If you agree, here's some valuable info on how to work with HRT's and the somewhat unique problems they pose. And, as luck would have it, the example is an unfinished size of...drum roll please...2.5" x 4.5". http://www.quiltdesignnw.com/PDF/HRT_2x4.pdf

make it larger by a half inch or so (see the math in the above posts) and then 'square up', which in this case means to trim to the size you want with the 60 deg angle... you must start out with more than you need or it will never work... just like the HST...we cut larger on purpose so there is something that allows us to trim up WITH the seam rather than the outside edge...

Jan--you nailed it--none of my rulers--even the new one--have the 60 line at the corner! That is why this is a struggle for me! I have about five square rulers or various sizes--it wouldn't have taken much to put one on! Sigh. I've made many HST with this trim method with perfect results... but at least now I know WHY I'm stuggling. Thanks you!

ghostrider--thank you for that link! I feel better I'm not the only one. lol

Joanne's has a 6.5" one on-line for $5, but I'll check the store first. It takes them a long time to get a package to its destination and the shipoping is more than the ruler.

Karla...a ruler isn't going to make it work with both the angles and side lengths you have given, finished or unfinished. It's just plain impossible. Save your money. The math doesn't work...just ask Pythagoras. See for yourself with this interactive triangle.
http://www.mathopenref.com/triangle306090.html
Or draw your 2.5 x 4.5 rectangle on graph paper, add the diagonal and use a protractor to measure the angles. None of them will be 60º...it's 90º, a bit more than 61º and a bit less than 29º. Those bits make a difference. Forget the angle and go with the side measurements so the HRT fits with the rest of the block. The instructions are just plain wrong.

I'm just going go draw a line on that will work. ;-)

I wonder if the Tri-Rec ruler would be helpful for this? I bought the ruler but
haven't used it yet. You can make Half Rectangle Triangles with it.

Hey EasyPeezy--I asked if the Tri-Rec would help when I posted the block--but no one answered. I have them, but haven't used them yet... I wonder too and will take a closer look. Thanks.

Let us know how the Tri-rec worked.