Introduction: Easiest Way to Make Octagons for Wood Turning. NO MATH OR MARKING! YAYY!
To turn a long piece of square wood into a shapely cylinder on the wood lathe, first your going to have to chop off the corners and turn it into an OCTAGON.
Now, I remember most of my high school trig and know a few ways of marking off corners and measuring to get that perfect octagon from a square, but oh the cosines and tangents and finding a pencil and ruler is such a bore!
Here's the absolute easiest way to do it on a table saw with an angle adjustment, like the one at San Jose Techshop.
Firstly, before you do anything, MAKE SURE THE SAW IS OFF! Unplug it, take out the key, do whatever you have to to ensure it cannot go off while you are laying things out.
Go ahead and tilt the saw to a 45 degree angle. All the way over!
Now is the "tricky" part where you really should have made sure the saw is absolutely de-powered.
Lie your square blank up against the blade so it lies flush against it. Don't push or lean on it, just set it up flush against the blade up on one corner.
Then, slide the fence in so its flush against the corner of the square. Lock it down.
Wallah! That's all the measuring done. Now you're set to cut the blank. Remove your block and re-establish all safeguards and power to the saw.
Now time to cut! Observing all safety steps, go ahead and slide your blank through one corner at a time until all four corners have been chopped, and you will have a perfect octagon, no measuring involved.
I used a feather board, helped keeping that stray chunk of corner from skipping around and kept the blank nice and tight against the fence. Just be careful where you put your hands, as that blade does come out the left side of the block when cutting the corner. Use the push stick if you want to.
Congrats, now turn some wood!
I made it at Techshop!