The S-shaped Curve – Oh, Geez
I woke up this morning knowing I had to write a blog post today on the topic of ogees. “Oh, geez,” was my first thought. “I don’t really know what an ogee is.” By noon, after looking at lots of pictures and write-ups, I had determined that an ogee is an S-shaped curve. Simple as that. Why didn’t anyone tell me – before it was already time for a lunch break?
With a healthy meal in me (salad), I realized I had been looking at an ogee in my Adirondack chair plans for several weeks. The arm brackets are little S-shaped curves. The reason I have been looking at these drawings for weeks is that, before today, I had no idea how I was going to draw and cut these curves efficiently, accurately and repeatedly. I figured by staring at the drawings long enough maybe some solution would occur to me.
There are a couple ways to draw an S-shaped curve. One method, of course, is freehand drawing. This is perfectly acceptable, and if you do it on a piece of scrap material you will then have a pattern with which to trace matching curves on each of your workpieces.
I want to limit the amount of pattern-making I have to do for this project, so I decided to go with the alternative method for drawing ogees. Christopher Schwarz wrote a post on this recently, but it’s hard to understand the process from a written series of steps. Megan Fitzpatrick then pointed me to a Roy Underhill video that is currently free on the PBS site. The video helped me understand the process better, and I am off and running on my arm brackets.
Oh Gee, the S-Shaped Curve is Everywhere in Woodworking
Now that my eyes and hands are trained for ogees, I am seeing these S-shaped curves in a lot of places. You’ll find them not only on board faces in woodworking, but also as profile cuts on mouldings or edges. Most woodworkers make these profile cuts on a router table, with a specialty router bit. But there are other ways. “Exercises in Woodworking” recommends that you teach yourself to cut an ogee profile with a gouge and chisel. And our latest DVD, “Make a Custom Ogee Moulding Plane,” is all about cutting the profile in repeatable fashion with a specialty handplane. Check it out!
The S-shaped curve is also used to depict growth over time on a line graph. It is fair to say that my knowledge of ogees, over the course of the day, has followed that trajectory!
How do you draw and cut curves in your woodworking?