Sunday, July 17, 2016

Ohio Star Block and Hourglass Units

Some quilting friends of mine are doing an Ohio Star swap, and they asked if I could make a tutorial on how to make them. Sure! I love to teach, and it gives me a goad to get the blog going again. A two-fer!

Ohio Star is one of those great, traditional blocks that keeps popping up over and over again. It looks great in a wide range of fabrics, from Civil War to solids, and can also be used to showcase a focus fabric. It can look just as at home in traditional, contemporary, and modern quilts. And it’s pretty easy to make, too, even if those hourglass units, and their quarter-square triangles, might give some people pause.

Built on a 9-patch grid, Ohio Star is made from 5 plain squares and four hourglass units. I’ll be making blocks that finish at 6” in this tutorial, so my units will need to finish at 2”. For a 9” finished block, I’d need units finishing at 3”, for a 12” block I’d need 4” units, and so on.

But before I start cutting, however, I have to iron my fabric with a good dose of starch. Do you remember that old Devo song, Whip It? Well, replace “whip” with “starch” and just keep that song on repeat in your heat every time you start a new quilt. Starch can be a quilter’s best friend! (Well, maybe second best. I think all that pretty fabric comes first!) A good starching will go a long way towards taming any bias stretch that might creep up in our quarter-square triangle hourglass units, and it won’t hurt the plain squares either.

Once the fabric has been starched, cutting the plain squares is pretty easy. I just add 1/2" to my finished size and cut four squares from my light blue background fabric and one square from my dark blue star fabric. In this case, I’m cutting four, 2-1/2” light blue squares and one, 2-1/2” dark blue square.

The hourglass units can be made using two different techniques, and which technique you use will determine how to cut your fabric.

Hourglass Method I: Whole squares

With this method, two large squares are cut and used to make two hourglass units. The size of the cut squares is determined by adding 1-1/4” to the finished size of the hourglass unit. In my case, 2” + 1-1/4” = 3-1/4”. Since I’m making four hourglass units, I need to cut two, 3-1/4” squares of light blue and two, 3-1/4” squares of dark blue.

Next, layer one light square on one dark square, right sides together. On the back of the light square, draw two lines 1/2" apart using a Quick Quarter tool and a chalk pencil (or the marking tool of your choice). Then sew just inside* each line. (Instead, you could draw a single diagonal line, and then sew a scant* 1/4" on each side of the line.)
*It is very important that you sew inside the double lines or use a scant 1/4" seam from the single line! Your hourglass block will be too small if you sew on the double line or use a full 1/4" seam.

Once both lines are sewn, put the sewn squares on the ironing board dark fabric facing up. Set the seams with the iron, gently finger press each seam open, and then use the iron to press the seams all the way before finally cutting the two halves apart. From my four starting squares, I now have four half-square triangle (HST) units.
Next, take two HST units and layer them right-sides together, butting the seams. You can make sure that they’re in the correct orientation if you peel back the top HST and see that the facing sides make the hourglass.

Now mark my double, diagonal lines again and sew just inside the lines. (Or you can mark a single diagonal line and sew a scant inch on each side of the line.) I placed pins outside my lines to make sure that my seams stayed butted together as I sewed.

Then it’s back to the ironing board to set the seams, finger press them open, press with the iron, and then cut the two halves apart. And, voila! Hourglass units! Now all that’s left is to square them up, and I’ll be ready to put the block together!

This hourglass unit will finish at 2”, which means that it has to be squared up to 2-1/2”. To do that, lay the ruler over the unit with the diagonal line over one of the diagonal seams. Half of 2-1/2” is 1-1/4’, so make sure that the 1-1/4” vertical and horizontal ruler markings are bulls-eyed right over the intersection of the unit’s diagonal seams. Next, make sure that each diagonal seam ends at either the 0” or a 2-1/2” marking at each corner. Once those are all lined up, trim away any excess slivers and the dog ears.

Hourglass Method II: Quarter-Square Triangles

With this method, we start with four QSTs to make each hourglass unit. There are two ways you can make your starting QSTs:
  1. Cut squares the same as we did in Method I, but, rather than layering and sewing them, cut on both diagonals on each square. This will give you four QSTs from each square. With one light square and one dark square, you’ll have enough QSTs to make two hourglass units.
  2.  If you have the Companion Angle ruler or the Fons & Porter Half and Quarter ruler, you can cut your QSTs from strips. To determine the width of the strip you’ll need, you have to know the height of your finished QST. Since my hourglass units will finish at 2”, and my QSTs (measured from the long, triangle base to the top of the center point) are half the height of the finished hourglass units, my QSTs will need to finish at 1”. Add a 1/2" seam allowance to the finished size, and I end up with 1” + 1/2" = 1-1/2”. I need strips that are 1-1/2” wide. Follow the instructions that came with your ruler to cut the triangles from the strip. This is a great way to use up those last bits of fabric that aren’t large enough to make the squares needed in Method I.

Sew the left leg or the right leg,
but make sure you sew the same leg on each unit!
Layer one light triangle on one dark triangle, right sides together. Sew going down one of the short legs of the triangles. It doesn’t matter whether you sew the left leg or the right leg, just make sure that you sew the same leg on both triangle pairs! Feed the triangles through your sewing machine flat edge first, and sew the seam with a scant 1/4" seam allowance. Also, I find it very helpful to use the tip of my seam ripper, a skewer, or an awl to steer my tringle tips as the last 1" or so of my fabric goes under my needle.

Set the closed seams with an iron. Very carefully finger press the units towards the darker fabric, and then very carefully press with an iron. This is a bias seam, so be gentle!

Layer the sewn triangle squares together, nesting the seams. I like to add a fine pin to hold the seams together. Again, sew with a scant 1/4" seam, press, finger press, and press again.

Now take that hourglass unit and square it up in the same manner that was shown in Method I.

Sewing the Units Together

This last step looks easy-peasy, I mean, you’re just sewing units into rows, and then sewing rows together, right? But, if you want your unit to come out to the correct size without losing any of your points, this is where sewing with the correct seam allowance, that scant 1/4", becomes critical.

When you’re finished sewing your block, it should measure 6-1/2” square, and the star points should all end 1/4" inside the edge of the block (i.e. – the points end at the edge of the block’s seam allowance).

  • If your blocks is smaller than 6-1/2”, then your seams when you sewed together your units was too large. Take the block apart and re-sew the units with a narrower seam.
  • If your Block is larger than 6-1/2” and the star points extend into the 1/4" seam allowance, then your seams were too narrow when you sewed the units together. If you just trim down your block to 6-1/2” at this point, you won’t leave yourself enough of a seam allowance, and you’ll end up cutting off all your points when you sew this block into your quilt. Instead, I highly recommend that you take the time to take apart the block, then sew the units back together with a slightly wider seam. Remember: “slightly wider” usually means only 1 or 2 threads wider. No, it doesn’t sound like much, but it will make a big difference!

Spice It Up!

Sometimes it can be fun to jazz up your Ohio Star by adding an accent color. The accent color replaces one QST in each hourglass block, and the blocks are turned so the accent color is adjacent to the center square.

These hourglass units can be sewn by cutting one QST of background fabric, one QST of the accent color, and two QSTs of your main star color, then sewing the triangles together as in Hourglass Method II above. However, contrast hourglass units can also be sewn using squares, as in Method I, and here’s how to do that…

Here are all the patches needed for one 6-1/2” block:
  • Background fabric ─ four 2-1/2” squares, plus one 3-1/4” square
  • Star fabric ─ one 2-1/2” square, plus two 3-1/4” squares
  • Accent fabric ─ one 3-1/4” square

Using the 3-1/4” squares, layer the background square right sides together on one star square, and layer the accent square right sides together on the second star square. Draw your line(s) as above, and sew.

Press as described above, and then cut the HST units apart. Make sure that the seams are pressed in the same direction on all four HST units. (i.e. ─ all seams pressed towards the star fabric, OR all seams pressed away from the star fabric.)

Layer one background HST and one accent HST together with the seams nesting together. This should orient the background fabric in the one HST over the star fabric in the HST it’s been layered with. Draw your line(s) and sew two seams as described earlier.

Sewn together in this orientation, those yellow QSTs
will form a pinwheel. The resulting block is known by many
names, including Big Dipper, Bow Ties, Whirling Blade,
and Yankee Puzzle!
Once these units are pressed and cut apart, you will have four hourglass units. Square them up, then sew them into your block!

Now that you’ve learned how to make hourglass units and Ohio Star blocks, go check out all the great quilts you can make with them! Here are a couple of links to Pinterest to get you started:

Happy sewing!


  1. Thank you! Great tutorial — I have the companion angle and was looking for extra info!

  2. I wanted to ask a question about this pattern I need to make the block 12 1/2 finished but I'm having a very hard time with the sizing. I cut my squares 5 1/2 and the came out to 4 1/2 hour glass but I'm not getting a 12 1/2 block can you tell me what size I need to cut my squares to get the 12 1/2 finished block. I have to make 12 blocks for a swap. Any advise would be very helpful. Thank you quilter in need!