Weekend Skill Building: Half RectangleTriangle (HRT's) Units and the Clearview 60 Degree Ruler

Here's where I split my prior post....

On to HRT's.  Another way to repurpose my ugly fabric (and frankly not so ugly in other forms than the 4 x 7 blocks that I cut it into). This size does not meet the Heighth being 2 x Width.  But the principles still apply with respect to getting the right headspace so that when the block is nestled to another at the points, the block yields a perfect point at the seam allowance (which is....1/4").

 I used these blocks in this repurposed way to figure out how to use my Clearview 60 ruler to ensure that my pointy tips at the top and the bottom of the block were appropriately blunted.  In fact, you can see the top right edge of this block shows the bluntness (1/8") that you are tryint to achieve.  (I sewed two halves exactly on the diagonal).

Note the points on the join of the two split rectangles on the left top and the bottom right.  That 'offset' looks off, but if you measure 1/4" in (e.g. the seam line when it gets pieced) it will be a perfect point.

Here's how I went about doing this experimentation.

Overall:   Now there is a big nuance and some smaller nuances  about these split rectangle units (or half rectangle triangles ("HRT") that I did not immediately appreciate, which makes them tricky buggers to be sure.  Surprisingly, there's not alot on the internet about half rectangles units...and there is some diversity about how to make them (as it is with its kissing cousin the HST).  As with most things, find the method that works best for you.  THIS method works well for me, but I already had the ruler.  Further, I did not see any expositions about using this ruler for this job.

1. First and foremost, don't go about it as you would half square triangle units (HST's).  You get a kite shape if you do.  And you may want that as a block component along the way...but not for an HRT.  Though admittedly it SEEMS so logical.  And for any of you who have had some oopsies' with paper pieceing triangles, you'll know that those angles don't always fold back the way you think!
2. Nuance 1:  Typical ratio is height = 2 x width. (My blocks were different).  You can make these two at a time--any many espouse this method.  Personally, I think that one at a time is more straightforward for me.  And I don't think that the 2 at a time method saves any more time. Find and stick to YOUR preference.
3. Nuance 2:  In piecing these together, you have a bias edge with an exceptional long taper.  Also, you have to have some overhang on either end (top overhangs bottom and bottom underhangs top).  That takes into consideration the 1/4" seam.  Basically the "v" notch that forms at the join of the bottom and top fabrics should be exactly 1/4" wide at where your needle starts to your right edge.
4. Nuance 3 (the Big One!):  When you piece these together, you will have a beautiful HRT, with the diagonal going directly through each corner except that....... you need to have about 1/8" width flat top on each point in order to have 1/4" head space above the join (just as you would any other point). This headspace is necessary or you will lose your point.  I call this a nuance, because it was not immediately clear to me of this necessity (and it is not a necessity in HST's).  You can achieve this a number of ways with a regular ruler, trim down template or a specialty ruler--anything that allows you to measure and trim to this perfect 1/4" sweetspot ( from top and from side).  I found many of the proposed methods difficult or too time consuming.  Further, none of the rulers that I put my hands on allowed me to both measure and trim in a way that I felt that the block was properly aligned with regular rulers.

I was disheartened.

I briefly considered (and still may do so)  getting a trim down ruler specifically for HRT. As I awoke this morning, it occured to me that my Clearview 60 degree ruler might be just what I need.  It was!  It worked beautifully with no awkward measuring.  Because the ruler has the 60 degree lines (whether using pointy tip or or long base) you can snuggle that line right up to your 60 degree diagonal seam.  By using the line markings, you can easily see where the sweet spot is to give you the necessary intersection (1/4" in and 1/4" down).  I bought this ruler on Ebay, used.  It looked brand new, and it was an exceptional value ($12 v. the $29 on Amazon.).  I also call that a win.

Below is a graphic that I hope show my explanation better.  This method works for taking a rectangular block and cutting it directly on the diagonal.  This is not for the 2 at a time trimming or other methods.  Frankly, this method seams easiest for me.

Click image to make bigger. The beauty of this method is it uses better anchor points (e.g. the diagonal and side) to measure your 1/4" down and over--the sweetspot which will give you a 1/8" flat top on your point and a perfect 1/4" join when you sew two blocks together using a 1/4" seam allowance.

Hopefully, the following is clear.  The light green rectangle is your sewn block. (Ideally it would be two different colors.

Notice the diagonal line.  That is your sewn line after you have pressed your rectangular block open (though it also happens to align with the ruler line as the two should be the same if you have sewn correctly.)

By working with the flat base of the ruler, you can take advantage of the top center section to perform these easy steps.  The way that the ruler is marked, you will have not problems in knowing if you are right because the diagonal lines (guidepost 1) , center line (guidepost 2) are both squaring guides.  Now if you have lined the diagonal and the cut edge up on the right, but your top edge that you are cutting is materially skewed, you may have a block construction problem (errors in cutting, sewing, pressing).  

1. Ensure the the point of your HRT is just right left of the center line of the ruler.
2. The cut edge of your block should be aligned with the center line.
3. The diagonal of your block should align exactly with the line on the ruler.  
4. The goal is to trim the top so that the sweet spot is exactly aligned against the diagonal and the right edge of the fabric (1/4" from top and 1/4" from the right).  
5. Once you have aligned the diagonal, the center edge and know that you have a point where you have a 1/4 measurement from the right, cut the top.  You have found the 1/4" width and the ruler is going to give you the 1/4" headspace.  
6.  Rinse and repeat with the other end of the block.Simply turn the block so that the pointy end is nestled against the left edge of the ruler. You will be working on the markings on the mirror (right) side of the ruler.  The other diagonals will be going in the way that you need to perform the same steps.