Thursday, March 23, 2017

turned sphere part 3.

I am preparing for my classes at Woodworkers Showcase at the end of next week and for the arrival Monday of a small film crew doing a video on Kindergarten in which my students will demonstrate "self activity"in the wood shop and in which I will explain the important relationship between the rise of Kindergarten and the rise of manual arts training in schools.

My mind/hand therapy has been to turn a hinged sphere from wood. In order to do so, I made 8 2-in. cube blocks, routed them to form hinge mortises in just the right places, and then glued the blocks together with brown paper between so that they could be turned on the lathe as shown.

The cuts in the side of the sphere are where the various hinges will fit between the segments when the ball is broken apart and rejoined.

Today I will install the hinges and see what I get. The objective is to make a segmented sphere as shown at the bottom of the second illustration.

 Make, fix, and create...


  1. Hi Doug,

    Out of interest, how are you turning the sphere? Are you freehanding it? How are you ensuring it's uniform?
    I don't do any turning myself, but wonder if its possible to turn a perfect sphere freehand, or are jigs involved.

  2. Matt, The turning was freehand with the shape judged at various points by eye and with caliper. What I turned is not a perfect sphere, but I followed some basic constraints. First it started as a cube So the outer edges (both ends and center) were left relatively untouched but for sanding. I turned 45 degree angle flats at both ends with the flats being roughly in proportion to the part at the center and at the ends. Then I began rounding, to make a smooth transition between the surfaces at the ends and at the center. I went by eye, but when I got close, I checked at various points with the caliper to see whether the dimensions were uniform.

    You can also make a simple template to check roundness as I demonstrate in my book, Making Classic Toys that Teach, where I show making a simple Kindergarten wooden ball on the lathe. I could have made a similar template in this case, but I was looking for proof of concept, not a perfect sphere.