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Plumb bob foundry

by on 10 Jun 2011

The synagogue frame is a scribe rule job. Without going into a full blown academic seminar on the history and technology of layout systems, this means that the various sections in the frame – walls, bents and plans in North American lingo – are first laid down in level establishments with all the pieces stacked in layers plumb above one another and the joinery lines transferred up and down between the layers. In the oldest and most sophisticated scribe rule traditions, the instrument used to locate these lines is a special plumb bob made for the purpose.

The plummet is cast in the shape of a doughnut, suspended from a wire crosshair centered in the doughnut hole, allowing the layout man or woman to sight through the hole and align the string over layout lines on the floor. Since one cannot buy these items in the local hardware store, we had to make our own. The following photo essay tells that story, with tooling courtesy of Guild member Tim Whitehouse.

The leveling plate

receives a mold made from the bottom of an aerosol can.

A pin hole in the center of the mold…

…engages the center plug which makes the hole.

But first the wire bale,

wound into trefoil shape,

must be engaged in the plug.

The wires are pulled tight and straight using a hook in a variable speed drill, and enagage in slots milled in the bottom of the plug.

Once the assembly is complete

Pewter is heated and poured.  The mold is filled,allowed to cool

Et voilà!

Appreciation and thanks to foundrywomen Clare, Jackie

and Sara.

Look for a demonstration of the tool in use in a future post.

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One Comment
  1. Dennis Marcom permalink

    Dzien dobry Pan Whitehouse. Splendid work spreading the gospel of the plomb!

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