Saturday, 4 February 2012

Challenge Accepted

For the second year in a row the Saskatchewan Woodworkers Guild, of which I am a member, has issued a challenge to its members known as the two by four challenge.  The criteria is simple.  You can build whatever you want, as long as you build it from a standard 2" x 4" by 8' spruce board.  The idea is to take something that is not normally associated with fine woodworking and do some fine woodworking.  I didn't take part last year, but this year I'm going to use it to do a test run for an idea that I have been kicking around for a few years.

Before I can actually start the piece itself however I need to make a form that I can use to do some bending.  The form is going to be a cylinder 30" tall and 8" in diameter.  I originally thought of using a cardboard form for making concrete footings, but the ones I could find were too flimsy and were out of round.  Instead, I decided to make my own out of wood.

The form is made out of the same spruce two by fours that my project will be made from.  after cutting the boards to length, I sliced them in half by running them through the table saw.  Then I used a bird's mouth bit in my router table to cut a notch along one edge of each board.  Here is a couple of shots of the setup.

Here is how the boards go together;

And this is the complete glue up.

There is a piece of plywood at both ends so I can put it in the lathe and turn it round.  Here's the problem.  It's too big to fit.

I didn't actually know that when I built it.  My lathe is an old craftsman that has a 36" bed and  12" swing.  The form is 30" long and about 8 1/2" in diameter.  This sounds like it should go on with no problem, doesn't it?

The reality is that with the tool rest on my lathe struggles to clear bowl blanks that are much larger than 8".  I had never actually pushed it quite this far with a spindle turning before.

When I tried to mount the form between centres that little bolt that keeps the wrench on got in the way.  After some trial and error I found that I could remove it, as long as I kept track of my wrench. With the bolt and the wrench off there was just enough clearance over the tool rest mount to get the form between centres.  There was not enough room, however, to get the tool rest into position and have the washer clamp down on the holder.  Vise grips to the rescue.

Once I had knocked the corners off, and with the clamp bolt tightened down past the base, I was able to replace the wrench and bolt.  I was worried that the vise grips would not hold well, but they were actually more secure than the regular system which has a tendency to pivot under heavy load.

Here is a shot of the form rough turned:

And finished.

Now I can actually start the project.  It has to be done for the Feb. 16th meeting, which means I better get cracking.

1 comment:

  1. Good luck with the project.
    We do something similar, but with a 4' piece of 1x8 pine.

    It's always interesting what people come up with.