Divide and conquer. Break it up into 15, 30 or 1 hour per day intervals. My friend did. She marked her squares at night and sewed in the morning then trimed at night, etc. She made 11 half square triangle quilts in a year.

This is brilliant!, Thank you. It looks like it'll end my dread of drawing all those lines!

Thank you, thank you for the helpful suggestions. Time is of the essence here and if I only had 20 or 30 of these triangles to make I wouldn't mind drawing the lines but 1000+ is quite a lot. I only have time to quilt on weekends so I need to get moving. When I started quilting I told myself I will finish one quilt before starting the next and I've been able to stick to that and I don't want to put this one aside.

I'm going to try one of the masking tape methods as that will eliminate the long drawn out task of drawing lines over and over. Or if that doesn't work I may try a few by cutting first and then, yes, sewing on the bias as mom-6 does. at 3" will they really get that distorted?

As for the trimming after the sewing is done, I like Eleanor Burns' way of doing it. She trims them down before opening them up and also trims the dog ears. It's nice if you have her ruler (I do), but it's not necessary. You just have to figure out where on your square ruler to place on the hst to be able to trim to the size you want. Trial and error. Gina

Since you are oversizing your HSTs and then trimming down to size, I recommend that you get the Quilt In A Day Triangle Square Up Ruler. It comes in 6-1/2" and 9" sizes, and you can find it t JoAnn's. The basic advantage to it for me is that after you have sewn and cut your squares in half, you trim BEFORE pressing open, so you only have to trim two sides.
https://www.quiltinaday.com/shoponline/rulers

Yes. If you are that invested in cutting them in half first and sewing them second, then I highly recommend starching the snot out of the fabric first. I speak gently and kindly from experience. :thumbup:

So many HST!!!!! I draw the line as I go. I draw corner to corner and then sew on either side, as a chain. Turn cut apart and repeat. Yes it is tedious. But if you cut first then you are sewing on the bias and triangle may stretch making quit a mess. I just made 102(204) and thought that was a pain. Take your time and divide squares into piles, sew all in the pile, do complete process on that pile and then on to the next. Should take same amount of time but is not as intimidating.

Rather than mark diagonal center line I press square in half diagonally then stitch 1/4 on each side of pressed line. If you have allowed a larger square set the trim is a piece of cake.

that's what I do. I typically will chain down one side for a bit then go back and stitch down the other side. just faster for me. But, if you're good a stitching along bias edges, it might be faster to cut them apart then stitch. As mentioned, time it out for yourself and see which works best for you.

Good Luck !!