# Thread: Making a Differential Cut UQ

1. ## Making a Differential Cut UQ

I'm going to make a 2/3 length radial quilt. Roughly 48"x54" with 2" or maybe 2.5" baffles. I understand the concept of differential cuts, but I'm not sure how much detail needs to go into the process in order to make a quality quilt.

The inside layer (touches the bottom of the hammock) will be 48"x54" (ignoring seam allowances). The outside layer will need to be bigger in both dimensions in order to accommodate both side-to-side and head-to-foot curvatures. The baffle height will be the primary factor in determining how much larger the outside layer will be. That I don't have issue with, besides it gives me a chance to use Trigonometry again**.

What about the baffles? Do I make the outer edge longer than the inner edge in order to compensate for the head-to-foot curvature? What about baffle spacing? If I put baffles every 6" on inside layer (7 baffles for 8 chambers), I think I'll have to compute the spacing I'll need to sew them to the outer layer since the outer layer will be wider than the inner layer, correct? This will result in slightly trapezoidal shaped chambers.

One more thing, which color should be the inside? When I made my top quilt I put black in the inside and a lighter color on the outside. Should I do the same with the UQ?

** I actually had to use the Laws of Sines/Cosines when I made my homemade 2# 3.5 person tarp-tent. Who said you don't need this stuff in real-life(tm)?

2. ## howdy Neighbor

I am also in the Columbus area. Set up your PM's so I can shoot you a message.

~Stormcrow

3. You don't need complicated formulas. I make my 'outside' covering 3" wider on all sides. That is the side material hanging under the hammock is 3" wider than the "up facing" or inner piece. So, when sewn together, the 'outer' covering is that 3" than the side towards the hammock, thus, 'differential'. When filled with down, it puffs up, and won't compress when tightened to the hammock to close up gaps. The baffels are also all 3". Even with darts aroung the sides and end, it's all cloth, and very forgiving. Of course, seam allowances are extra. Shock cord suspension channels can be added around the edges after the quilt is baffeled and sewn together.

4. Originally Posted by psyculman
You don't need complicated formulas. I make my 'outside' covering 3" wider on all sides. That is the side material hanging under the hammock is 3" wider than the "up facing" or inner piece.
You just sew the baffles to the outer layer "straight across" from the inner layer?
Shock cord suspension channels can be added around the edges after the quilt is baffeled and sewn together.
You sew on channels after making the quilt? Do you use side channels for the shock cord, or just tie it the the 4 corners?

3", I assume that is a winter UQ, right? What diameter of shock cord do you use?