Have you ever been in a situation where you want to draw a nice curve but don't have the proper tools? This happens to me all the time when drawing up a project. Usually I look around the house to find large bowls or anything that I can use as a tracing utensil and this actually works most of the time, but not always. The other day I was working on designing a bar stool and it required a long arc. Simple I thought I would just use a flexible straight edge and pencil it in. The trouble I ran into is that I needed either A, a shop buddy or B, two more hands. Again scrounging around in the shop I got it figured. A Ratchet strap!
I use these 1/8" thick straight edges all the time because they are flexible and spring back fairly well. Combined with a ratchet strap along its length you can turn the straight edge into a drawing bow. Tension it more or less depending on the desired arc that you want and when you let go, it stays in place. Since my straight edges from end to end are accurate to whatever length it is all you have to do is line up your center line with 18" say on a 36" straight edge, or 24" on a 48" and so on. If you are looking for an oblong arc then you can line up anywhere but the center line and it will be repeatable each time. Hope you found this useful. Below is a few amazon affiliate links to the items I use. If you decide to purchase these items please use these links to help support my little tips. Enjoy!