Originally Posted by QuiltE
It's not just the height of the table ... also the height your machine sits at. Eg. most portable machines sit on top of the table, so that raises it higher still. Also, the chair height you are using
So for the ergonomics of things ... think right angles and you've got it sorted out.
Chair ... sit with your legs/hips at a little more than 90°; also feet flat on the floor, knees 90°. I bought a drafting chair, which let me get higher than a normal office chair.
Sewing surface ... elbows again bent about 90° will determine where your sewing surface should be.
Table height ... the above determines the table height. And remember, if your sewing machine sits on top, instead of into the table, the table height is different.
That's the ergonomics that I've been told ... though you need to see what works best for you and adapt from there.
The same right angles spill over to your cutting surface ... stand at the table, and be able to stand straight and tall, as you cut. So 90° for your elbows bent and touching the cutting surface determines the height.
Thank you for this, QuiltE! Ever since I began piecing quilts in earnest about 8 months ago, I've had trouble with both my median and ulnar nerves (symptoms: both sides of both my hands go numb when I sleep with my arms in a flexed position). I finally realized that sewing and these symptoms were correlated.
But I didn't know how to fix the problem. Your 90 degree suggestion sounds right to me. I'll give it a try!