-
The circumference of the bottom disc also has to be 28"
Once you have set the size of the tube it can't grow.
If you make the disc bigger you will just end up with excess fabric around the edge when you sew to the quarters.
Ideally you need to set the size of the disc as you want it to end up after completion. Then add your seam allowance to the outside of it, then measure the circumference. The tube is then that size, plus whatever seam allowance you want to close the tube on each end. Because you have a closed tube already, the disc can't have a bigger circumference than the tube.
Black_Rainbow_Project-
Fuck me, I’ve struggled with this for ages and just kept messing up. This makes so much sense, thanks. Hopefully my next attempt at a round bag will finally be round.
-
I found an online converter that gives me a diameter of 9.2" including seam. Will see how that goes tomorrow. Starting from the base makes more sense, I'll try that next time.
Tijmen
moocher
I'm sewing up a round bottomed bag. So far done the side, so an open tube in effect. If I lay this flat then it measures 14inches across giving me a circumference of 28 inches.
Say I want a seam of half an inch all round, then is the circumference of my bottom circle going to be 29 inches? Right? Surely.