Thursday, August 18, 2022

Nutshell Pram EXCUSE ME 18 Aug 22 Thwart Patterns

18 Aug 22:

We're a week or two behind on the blog, so we'll jump forward to a few days ago and fill in blanks later. We are making patterns for the thwarts in the Nutshell Pram using a technique from the Wooden Boat School video series, so why not start with the hardest one, the middle thwart? It has a frame that we have to trim around, but, if we chowder it up, it is also the widest thwart, so we can try again with the butchered piece on the narrower bow or stern thwart.

First we needed to decide how wide fore and aft our seat will be. Plans call for 8 inches, but that was 40 years ago, so we are bumping it out to 9 1/2 inches. This will let us know how wide to make the pattern piece.


We use a calibrated Tips From a Shipwright carpenter's pencil to set the slat width, happens to be 1/4 inch.


We cut two pattern bits of the same thickness stock and to the same width...




...and attached them to crosswise braces.You may note where the frames intrude, we have to scribe around that, find the plank bevel and also scribe the fore an aft plank curve.


We used a small scrap od wood to bring the fore and aft plank curve over to the pattern piece. And a straight edge to extend the side markings for the frame.


Side plank bevel scribed fore and aft to the pattern piece.


Here we marked out how far the frame intrudes into the thwart.


We placed the bevel under the pattern piece and against the side plank. This will show us the top to bottom bevel on the end of the thwart. I used a different pocket bevel on each side to see if the bevels matched, and they did, so the boat is not twisted.


Next we'll cut those bevels and scribe lines, then we can slide the pattern pieces all the wat outboard to check the fit against planks and frames.

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