Re shifting the fence — I’m glad you’ve mentioned that because 诲辞苍’迟 have a way here to send a sketch, and I neglected to emphasize that if you do what I’m attempting to describe (as I think you’re describing too), you are slicing off a LOWER edge of your square pole. ?(With your pole sitting in a lopsided vee between fence and blade.)

I hope so because I 诲辞苍’迟 think you want to set up the fence and blade to slice off an upper edge. Some experts might possibly know of exceptions, but i 诲辞苍’迟 think you ever want to trap a workpiece under a sloping blade, between the blade and the fence, because if the stick ever goes out of line and the blade gets too good a hold of it, that will set up a classic kickback event. ?Such as have been known to impale people.

Octagons not good enough? ?Oy. ?Not this week, I’m supposed to be loading a truck with our belongings and they’re not even all boxed yet. ?Misjudged how soon my big strong son would be done with his (now online) schoolwork and could help me.

There does have to be some theoretical plane of the blade that would let you use the same trick — i.e., tilt up the corner of the stick to define the desired fence distance. ?(And then having set the fence, reset the blade to 30 degrees off vertical and make your cuts.) ?What’s less clear to me is whether that desired initial blade plane is within the 45-degree range the blade can actually go to. ?I did sketch at it for a little while (can you tell I’m avoiding something?) but I didn’t see a clear way to define the angle without plowing into equations with a calculator. ?Many angles in the sketch are 30’s and 60’s, but then the angle of the desired edge below the middle of the side is 15, and that makes the angle I want to find look messy. ? When I allow myself to come back to it, I think I’ll punt the math and draw it up in Onshape, and just let the software tell me what the angle is. ?(Do you know about Onshape? It’s a cloud-based full-blown 3D solid-modeling CAD app by the same guy who launched Solidworks. ?if you’re willing for your work to be accessible to others, the subscription is free.) ?(But then there’s also FreeCad, which lives on your own machine and is as private as you like, but it’s less debugged because it’s designed and coded entirely by volunteers. ?So it’s still beta, but very impressive that it even works.)

Disclaimer: ?the octagon trick is not my discovery, I only verified it (so as to believe it). ?I thought it was pretty slick too. ?I was told it by my friend Dennis Goodrum — a guy who pulled off transferring into MIT at 38 from a Wisconsin junior college and was formerly a carpenter — so this is presumably carpenter lore, from such guys as know what all the engravings on a rafter square are about.

At the time, by the way, I was doing a research project on how MIT kids who are such whippersnappers on paper can very often be so clueless in the shop. ?(I suspect it’s just because being rewarded for bookwormery means you may not be very motivated to get your nose out of your books. ?But it was interesting to find an inverse correlation between the mechanical comprehension I was assessing and the MIT GPAs of those same students.) ?

Dennis signed up for one of my research interviews. ?I had two topics, one on structure and one on power transmission (ways to gear down a wimpy motor), and I normally interviewed each volunteer on either one or the other. ?Dennis blew away the first topic in half the normal time, so I also gave him the other one, and he did the same on that one too.

More next week some time, if you haven’t done the trig yourself by then —

Crispin

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