SketchUp Drawing Of Seatboard With Dimensions One of the more important components in a clock case is the seatboard. The seatboard is the board on which the clockworks is mounted and secured. Its placement determines the vertical and horizontal centering of the hour and minute shaft relative to the clock face. It also determines the clearance, or depth of the shaft relative to the clock face.

Drilling Large Chain Holes With Forstner BitThe seatboard consists of a number of holes that must be accurately placed. Two small holes are for threaded pins that secure the works to the seatboard. When installed in the clock the seatboard itself is fixed (no mechanism for adjustment). The positioning of the works on the seatboard directly affects all positioning mentioned in the previous paragraph. So these holes too must be accurate.

Roughing Out The Pendulum Rectangle With A Sabre Saw Since this is a chain driven clock there are four larger holes that allow the chains to move freely and hang in the pendulum cabinet (lower section of the clock). These holes need to be large enough to permit “pulling” the weights once a week for winding and to ensure no interference as the weights slowly drop while driving the clock.

Scrap Wood And Double Sided Sticky Tape Form A Template One rectangular hole is needed to allow the pendulum to pass through and swing. This hole does not require critical dimensions, simply enough room for clearance.

If you have been following this project on my blog, you know that the clock works for this project came with no documentation. I had to reverse engineer the seatboard design by taking very careful and difficult measurements of small, and deeply imbedded parts in the clockworks. I am sure you are asking yourself, “How can this be difficult? After all, there are only four holes we are talking about”. Well, let me assure you that positioning a 6” steel pocket rule inside the delicate works of a chain driven clock to make accurate measurements is all but impossible.

The Finished SeatboardI meticulously took measurements and used them to create shop drawings. After milling my first seatboard and mounting the works, I made further measurements to test whether alignment in the final clock would be correct. This resulted in changing the position of three out of six holes.

A Test Mount Of The Clockworks On The Seatboard I corrected the shop drawings, milled another seatboard and tested again. This time everything worked out perfectly.

Milling this component provided the first opportunity for me to use my new Supreme Drill Press Table purchase from Peachtree Woodworking Supply, Inc. It worked like a charm, allowing me to quickly, accurately and repeatedly drill the holes. For the larger holes I used a Forstner bit with a backing board to ensure no tear out of the opposite side.

The rectangular hole was a three step process. First I drilled two holes, near each end and inside the rectangle, and large enough to accommodate a sabre saw. Second, I used the sabre saw to rough out the rectangle. Lastly I used scrap wood pieces and double sided tape to form a a template for a template router bit to follow. The completed seatboard is shown above.

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One Response to “A Seatboard For A Tall Shaker Wall Clock”

  1. Summer says:

    Looking good, Dad! I can’t wait to see it finished!