Help with HST size
 

I've misplaced my HST cheat sheet for sizes. Wanting to make the two at a time HST that will finish off at the size of a charm square or 5". Making them little larger and having to cut down is not a problem for me as I have a Loc-Bloc for that...just not wanting to waste too much fabric. Thank You!

Ok, doing this by brain power with very little coffee. I usually cut large and trim down. If I understand, you want to take a square, divide it along the diagonal and make two HST units.

Although our usual 1/4" seam allowance works great with right angles, the math for the point is to add 7/8th -- which I just round up to 1".

5" (finished) + 1" seam makes the diagonal seam a little tight for a 6" square. I personally would cut at 6.25 as having a slight trim down. Try it and maybe do 6.5" with more trim.

I use a "quilter's foot" on my machine that is 1/4" left and right and also has marks front and back. I do typically draw the line down the middle and then use my foot to offset the correct seam allowance, and then cut the diagonal after sewing.

Theoretcal formula:

Cut squares 7/8 " larger than you want the finished HSTunits to be.
Example: two 5-7/8 squares would yield two 5 inch Hst unis. ( 4.5 finished size)
this ALWAYS results in my HSTs being too small - even when I use super scant 1/4 inch sean allowances

If I cut my squares 1-1/8 larger, this gives me a bit of wiggle room.

Example: two 6-1/8 squares would probably give me two 5 - inch HST units if i use my " regular" quarter inch seam.

I think this something you might need to experiment with to find out what works for you. There are variations in rulers and cutting methods, seam allowances, and even pressing.

Unwashed fabric may shrink if it is pressed with steam.

Here's the cheat sheet for Bloc Loc two at a time HST's.
https://onl.ae6.myftpupload.com/wp-c...TAAT-CHART.pdf

And if you need other Bloc Loc cheat sheets, here's the link.
https://blocloc.com/pdf-files/

The rule is add 7/8 to finished size you want it to be.

I have a Creative Grids ruler that has only markings every 7/8 inch. It is such a saver of brain power and time for me.

I add 1" to the desired finished size and use my Bloc-Loc to cut down.

That said, if you want to mix in your charm squares, remember that they will finish at 4.5", not 5". So you probably want to make your HST's finish at 4.5". For me, that would mean cutting them at 5.5".