By Duane Sellman of Sellman Log Structures
Reprinted from Spring 2012 Newsletter
The timber frame (my first) I have been working on has an octagon shape in one corner. It is 16’ across and the 8 sided king post is 14” in diameter. To get a 14” diameter up the log, I cut the butt section off a 50’ log with a 24” diameter butt cut. After positioning and tracing the octagon template on both ends of the log, I cut the first 4 sides on my Woodmiser sawmill after shimming the tip up appropriately. After the first 4 sides were cut, I used a 45º block to cut the 5th side at the proper angle and so on.
I decided to dress up the bottom end of the king post with an “onion” carving. Granted, I have not seen an 8 sided pointed onion either, but that is what it came to be called. It also reminds me of the Greek Orthodox church steeples I have seen in Canada.
Anyway, I made a plywood jig to get the proper curves. I used Ed Miller’s “tracer” guides on the chainsaw to slide along the jig. If you are not familiar with these, they keep the cutting teeth the same distance from the jig whether the bar is plumb or vertical. So I rough cut this shape and then laid the bar on its side to brush the wood down to the jig.
The jig prevents me from ever cutting too deep – sort of! I positioned the jig on all 8 sides and cut the proper shape. Then a little sanding and presto!!! I have a decorative wood onion.
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