Full Chisel Blog

November 7, 2011

Patternmaking is not that easy.

Filed under: Documentation,Finishing,Historical Material,Of Interest,Proper Tools,Techniques — Stephen Shepherd @ 10:02 am

I have made a couple of small patterns for casting in silver and one in brass but this is my first patterns for casting steel.  Steel shrinks 1/4″ per foot when it is cast, these are built to the exact size of the drawings, and because they are small there will be little shrinkage.

The pattern on the right is a leaf forming tool and the tang fits in the hardy hole of a blacksmith’s anvil and was a straight forward job of just copying the original and the full size drawing.  The top part is pine and the tang is aspen, because it was the right thickness.

The one on the left is a German style pattern to fit in a hardy hole of an anvil, however it would also be a very handy anvil for any woodworker and a square hole in the bench like a bench dog hole could accommodate.  I am getting one of the first ones.  It is made with basswood for the top and pine the base and aspen for the square tang.

I had a problem with the anvil, well I had two problems; first the round horn, I copied the drawing [my mistake, it was drawn incorrectly], so I had to add to the bottom of the round horn to make it round.  The second problem was mine, in that the square horn was off by several degrees on the angles.

My solution was to cut it most of the way through, clamp it, cut it again and again until I could bend it so the angles matched.  I then glued it with Fish Glue, clamped it and allowed it to dry overnight.  Then a bit of filling, a coat of Moses T’s St. John’s Oil and a couple of coats of shellac.

I then gave them several coats of white oil based paint, lightly sanding between coats.

When taken to the foundry it was determined that the anvil needed to be cut in half, so I did.

To compensate for the saw kerf, I glued a piece of Spanish Cedar veneer to each side of the pattern and allowed to dry.  I cut off the excess, repeated the finish schedule and they are ready for the foundry this afternoon.

Fun project, now I have to make a pattern for a bridging tool.

Stephen

 

2 Comments »

  1. Years ago I worked for one summer with a patternmaker who was between jobs. Hands down, he was the most highly skilled craftsman I’ve ever known.

    Comment by Gary Roberts — November 7, 2011 @ 6:48 pm

  2. I’m eager to see this process to the end. Kudos!

    Comment by Gounthar Frankfurt (France) — November 8, 2011 @ 4:43 am

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