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Crotch Piece: What now?

Darryl Fective

Darryl Fective

Joined
Jan 20, 2011
Messages
713
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788
Location
Traverse City, MI
A local park did some tree trimming and removal last weekmultiple l, yielding multiple log piles. Another club member had stopped and talked to the crew and they said an excavation contrator would be loading (and probably disposing) the logs on Monday. (yesterday) It was a mix of red and white oak, so I went and loaded a couple truckloads over the weekend.

I split a white oak crotch thru the piths and put it on the lathe. The bark side was pretty ripped up so a natural edge wasn't possible, so I thought trying this style (not sure what it's called) of keeping a large rim and the chainsaw cuts might be cool. I wanted to maximize the feather grain and pictured a small bowl in the center. As I was cutting the backside, the grain of a larger bowl was sort of nice looking too, lending the option of a larger bowl.

It was getting close to dinner time (I do the cooking at home) so I slapped on some walnut oil (excited to see what it looked like) and bagged it up. I can't decide on bowl size proportion-wise and best grain. I'm also a littel stumped as to how to take thickness measurements on the bowl when I get to that point. It's sort of cool looking, but it's sort of making me feel like a beginner again. 😵‍💫


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My wife said I should try to finish the front with just a small, very shallow bowl on the front, then part off the bowl from the backside. Then we'd have an artsy hanging wall piece plus a usable bowl with cool grain.
 
Hi, as far as calipers, I know some of the folks on here use wire coat hangers. I suspect that would get you as far in as you need. I would also consider making a platter out of that piece. The feathering up in the sap wood webbing is really nice but generally pretty thin. The only way to capture it, often, is in a platter.
Actually as I look at it, it already has a bit of a slope to it, I think. So a very wide gentle slope bowl might work. Something like this but shallower. I couldn't find much on google
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I have small and large calipers, one arm straight and the other with a significant semicircle curve, meeting at the ends. A small nut is adjusted to take up the slack, then the caliper removed and the resulting gap between the ends shows the bowl thickness. A whole lot faster and easier than my poor description. I believe they are Veritas brand, sold by Lee Valley.
 
Can you think outside the box? Instead of thinking calipers and all that...it looks like you might have a known true center point on the tenon there. Can you measure the diameter of the outside of the bowl on the bottom, then use the radius from that, a pin in that hole, and a piece of string to help you draw a couple of circles? One at the outer edge of the bowl from the bottom, and then maybe knock off some X distance off that radius and draw another circle, for where you want your inside cut to be? At least, that whould give you a starting point. From there...you may just have to finger-feel it until you are satisfied with the thickness you can feel? I suspect using a scraper to deal with final wood removal down to the desired thickness would probably be a safer bet than using a gouge, too...
 
I wouldn't bother with calipers.
Drill a depth hole for the bottom, measure the radius you want for the rim - and make a nice curve from the rim to the bottom. Your body has muscle memory for the interior curve of one of your bowls.
Feel the wall thickness - one hand outside the other inside. Your body is fairly good at knowing where your fingers are relative to each other (proprioception) and you'll be able to tell if the wall feels too thick. More importantly (and easier) is if the wall feels an even thickness. You can play with that feeling and develop confidence in it with other bowls - close your eyes and feel, then compare with what the calipers say.
Nobody that sees or uses this bowl will have any better means of critiquing it than that.
 
I can probably figure out the measurement part. I'm still undecided about how the final piece should look. I Like the face of it that I have and cutting a small bowl seems like it could work well. When I flip it over, I also like the backside and the grain/proportion of the bowl shape I have. (although it would need a little modification/reshaping to not be too flat on the bottom) Going with that would lose some of the front face.

An ideal solution would be to get a coring knife in behind to save the larger bowl, but that's not happening. Maybe I will have some shop time today to just compromise between the 2 options.
 
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