How to Make Half Square Triangles (HSTs) :: A Finish-A-Long Tutorial

Hello and welcome if you have popped over as part of the 2017 Finish-A-Long tutorials.  I am up first and was a little bit daunted ...... but having worked a lot with half square triangles (HSTs) recently it made sense to write up my findings.  

I hope you enjoy the various methods of making these cute little blocks.  I love the size of 2 1/2" squares, they are kind of my go-to size for squares, so the following tutorial is based on that size.

2 AT A TIME HSTs

This method can be used if you want 2 HSTs in the same colourway

The general formula for this method is to add 7/8" to the finished size you require, therefore to obtain a 2" finished, ie 2 1/2" unfinished, you need to cut 2 7/8" squares

However, I find I always have problems with how wonky my HST turns out and it's nearly always undersized

To rectify that and achieve 2 1/2" unfinished squares cut a 3" square from your two fabrics

Draw a diagonal line, corner to corner, on one of the squares

Place fabrics right sides together as accurately as possible

Sew a line of stitching 1/4" away from the line on either side

I tend to move my needle position over one click so that it is a scant 1/4" seam

Place ruler on pencil diagonal line and cut

Below you will see the difference that extra 1/4" makes and also I pressed some seams open and some to the side:

Top left - this is using 3" squares and seam is pressed to the side

Top right - this is using 3" squares and seam is pressed open

Bottom left - this is using 2 7/8" squares and seam is pressed to the side

Bottom right - this is using 2 7/8" squares and seam is pressed open

Both the examples using the 3" squares result in enough fabric to trim to 2 1/2" and have good true squares, with the join in the middle

Both of the bottom examples are undersized and so I would need to do again (I know other people get good results with this method so please share your tips if you do!)

And trimmed!

4 AT A TIME HSTs

This method can be used if you want 4 HSTs in the same colourway

To achieve 2 1/2" unfinished squares cut a 4" square from your two fabrics

Place the squares right sides together, as accurately as possible, and sew a 1/4" seam around the outside

Cut from corner to corner one way, do not move them, and then cut corner to corner the other way

You end up with 4 HSTs measuring 2 1/2"

I press my seams open to minimise any movement of the fabric when pressing and hopefully achieve true squares

Trim the dog ears and you are ready to go!

If you like to press your seams to one side I would cut the initial squares to 4 1/4" to allow a little wriggle room and then trim to 2 1/2"

8 AT A TIME HSTs

This method can be used if you want 8 HSTs in the same colourway

To achieve 2 1/2" unfinished squares cut a 6" square from your two fabrics

Draw two diagonal lines, corner to corner on one of the squares

Place fabrics right sides together as accurately as possible

Sew a line of stitching a 1/4" away from the line on either side

Repeat for the other line

I tend to move my needle position over one click so that it is a scant 1/4" seam

I also tend to shorten my stitch length to 2 because the stitching is going to be cut (this is something new to me and I don't always remember as you may be able to see one stitch line is in my regular 2.5!) - I find this helps with keep the seams together when they are being handled and joined

Place ruler through the centre cross and align top and bottom squarely - cut

Rotate the ruler by 90 degrees and repeat

Place ruler on a diagonal pencil line and cut

Rotate the ruler onto the other diagonal pencil line and cut

You end up with 8 HSTs measuring slightly more than 2 1/2"

Trim HSTs to 2 1/2"

I use a smaller cutting ruler, this one is 4 1/2" square, and line up the 45 degree line with the join line in the fabric

Trim two sides and then rotate the block and trim the other two sides to 2 1/2"

I do own a 2 1/2" cutting square which would mean I would not have to pick up the ruler, rotate the fabric and replace the ruler, but then I am cutting at funny angles and, alas, I do not yet own a rotating cutting mat!

I also know Bloc-Loc rulers make this job easy but to use them you need to press your seams to the side

And there you have 8 HSTs ready for your block or project

Now what do you do if you don't necessarily want to double (quadruple or octuple - is that even a word?) up on your HSTs?  You sew on the bias.  Please don't look away it really is not scary!

1 AT A TIME HSTs - in different colourways!

Cut 3" squares from your fabric

Cut each square in half along the diagonal, from corner to corner

These cut edges are now on the bias, which is a much more unstable grain of the fabric - it will pull out of shape quite easily if manhandled

However, handled carefully it really is easy to sew - no matter what you have heard before!!

Place fabric in required colour pattern

Sew along the long bias edge with a 1/4" seam, taking care not to pull the fabric whilst sewing

You end up with HSTs that can be trimmed to the required 2 1/2"

The beauty of this method is you can see your design ahead of time and it is especially useful if you design and sew quilts ad hoc using a design wall

Phew this has turned into an epic post!!  I have some more I want to share with you but think that will have to be for another day.  It is actually my favourite way of making HSTs and flying geese units - be sure to pop back if you are interested!

The linky party for all your gorgeous finishes is now open - head over here to link up. Whilst there is a link page on each Host's blog they are all connected so just link up each project once and it doesn't matter where you do it.  Also if you haven't had time to blog about a finish you can always link up an Instagram post.  Looking forward to seeing all the finishes this quarter. x