How Do I Stop This

[Blackie]

https://db.tt/Gpyz1wk2

[Blackie]

I got wrinkles on the last bit of lacing, seat turned out great until the last ten holes! All holes were equal. What gives?

https://db.tt/8FrJpa16

https://db.tt/8FrJpa16

https://db.tt/xKHRq9Dx

[misha01]

I would guess that the circumference of the round panel is greater than the length of your side strip.

[Blackie]

I made both top and bottom the same, bottom came out smooth, but not top, I think it has to do with the added padding, but I'm not sure why. My side piece was cut to the exact measurement of the circumference.

[Nuttish]

Misha01 is correct.

This is a common problem in sewing scallops or convex curves in fabric. Unfortunately strategies for solving the problem in fabric don't apply to work using the weight of leather you are.

I'll leave you to puzzle out the high school geometry problem of calculating the outside diameter of your inside circle given the outside diameter of the outer circle. You will have the exact same number of holes on the top and side pieces, but (assuming you want your top piece flush with the edges) for any arbitrary arc length, the stitches per inch on the inside piece minus your stitching allowance (in other words, it's a circle from which you start your stitch that's perhaps 4mm smaller diameter) must take into account its diameter including the thickness of the outer piece. You'll also have to ensure that your stitching allowance is close enough to the inside edge of the outer piece so that it doesn't pucker on the inside instead of the outside.

Simply put, the inside circle of your truly creepy iron cross box is too large and the heavy tight lacing you're using is holding the piece down while it compresses and distorts it from the edge.

Sorry for the length of this post or any clarity problems. I'm happy to explain further and draw the solution.

[Blackie]

Please draw the solution, I'm lost!

Creepy? Ya think? Its a bar stool for a biker, so creepy works well!

[misha01]

I see what Nuttish is saying, but I'm not sure how to fix it exactly.

Let's say you want to make a pillow with a 10" diameter. For the side piece you would then need (10x3.14) 31.4" of material, right? But if your leather is 0.125" thick (1/8), and you make a circle out of the 31.4" strip, then the circle created on the flesh side of the leather would be of 9.75" (10"- 0.125 - 0.125) in diameter and only require 30.6" of material. So you are getting some compression when you make a circle out of your 31.4" strip.

I hope that makes sense, otherwise Nuttish can clear that up with his drawing. I'm not sure how to fix your problem because I haven't made one of those before. But my first thought was to bevel the inside edge of the side strip.