rschoenm

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The largest regular hexagon (six equal sides) you can get out of a 4 by 4 has sides that are 1.75 inches long; see attached image, right side.If you don’t mind stretching the hexagon you can get four sides that are about 2 inches long, and two sides that are just short of 1.5 inches; see image, left side. Other six-sided polygons are possible if you don’t need 120 degree angles all around.To make a regular hexagon from the 4 by 4, the diameter D = 3.5 inches. Start with the blank milled to 3.5 inches by 3.03 inches, then follow the Instructable.

Hello, for a 4 by 4 I would rather cut it into an octagon like this:https://www.instructables.com/id/Easiest-way-to-make-octagons-for-wood-turning-NO-/This leaves you with a little more wood than a hexagonal cross section.

Yes, cork pads/sticks would work, and so would short pieces of vinyl/rubber tubing. As with any clamp, you want to protect your work piece with pads or scrap pieces of wood to prevent it from marring or denting.

Yes, it would be complicated.

That might work somewhat, but the tube would be cut by the blade along with the dowel. You would still have support on the uncut portion of the dowel.

Very nice project and great write-up. I especially like your paragraph on making these things for people you love and how you would go broke if you tried to make them for profit - well put and my sentiment exactly! It certainly applies to my last project as well: https://www.instructables.com/id/Nested-Helix/Now I need to make an ‘Impossible Keychain’! Keep up the good work!

That is so cool, thanks for sharing. Looks like you cut a pretty nice first spiral! Please keep us posted on your further progress.I use the same DeWalt scroll saw and I tension the blade according to their recommendation. I listen to the ‘note’ when you plug the blade; typically the tensioning dial is around 3. Make sure the blade deflection isn’t so much that it cuts into the scroll saw table. Blades will break, especially when they exit the wood; so for good measure I leave about 3/4” at the end of the cut and trim that off later. When you get to the end of a spiral cut, make another slow cut while rotating the dowel 360 degrees without advancing it; this will cut the spiral loose. Some of my pictures show the ends still attached. If the blade gets pinched fro...see more »That is so cool, thanks for sharing. Looks like you cut a pretty nice first spiral! Please keep us posted on your further progress.I use the same DeWalt scroll saw and I tension the blade according to their recommendation. I listen to the ‘note’ when you plug the blade; typically the tensioning dial is around 3. Make sure the blade deflection isn’t so much that it cuts into the scroll saw table. Blades will break, especially when they exit the wood; so for good measure I leave about 3/4” at the end of the cut and trim that off later. When you get to the end of a spiral cut, make another slow cut while rotating the dowel 360 degrees without advancing it; this will cut the spiral loose. Some of my pictures show the ends still attached. If the blade gets pinched from vibration/deflection it will probably break; so try to avoid that.The saw speed that works for me is from 6 to 7.5 on the dial; higher is better if it doesn’t cause resonance.My advance speed is somewhere around 10” per 30 minutes, or 1/3” per minute for a pitch of 1.5” per revolution. Slow down or speed up depending on how much wood you cut - i.e. offset, tilt angle, pitch. Looks like your 1/4” per minute advance speed gave you a very nice/smooth cut surface.Blades will break, keep a bunch on hand. I use a blade for two to three cuts of 10” dowels.Other than that, experiment with different settings, and share what you learn!

Thanks for your comment.I am working on an Instructable for the Spiral Cutting Jig but it will take me a while. I want to rebuild my jig and document the build. For the programming I am using the Arduino IDE, and the examples that come with the Big Easy Stepper Motor Driver get you 95% to your final program. It does not involve gcode, you basically tell the stepper motors: turn some steps on the spindle motor, wait, turn the dowel motor one step, wait, repeat! LinuxCNC and gcode should work fine as well.I build the ‘gear box’ - i.e. the motor/pulley mounts from 3mm clear acrylic cut on a laser cutter. The jig uses several brass bushings, stainless steel couplings, timing belt(10”) and pulleys, and 1/4” nuts and bolts. The jig header is 3/4” baltic birch pl...see more »Thanks for your comment.I am working on an Instructable for the Spiral Cutting Jig but it will take me a while. I want to rebuild my jig and document the build. For the programming I am using the Arduino IDE, and the examples that come with the Big Easy Stepper Motor Driver get you 95% to your final program. It does not involve gcode, you basically tell the stepper motors: turn some steps on the spindle motor, wait, turn the dowel motor one step, wait, repeat! LinuxCNC and gcode should work fine as well.I build the ‘gear box’ - i.e. the motor/pulley mounts from 3mm clear acrylic cut on a laser cutter. The jig uses several brass bushings, stainless steel couplings, timing belt(10”) and pulleys, and 1/4” nuts and bolts. The jig header is 3/4” baltic birch plywood, the body is particle board and MDF(because I had some - baltic birch would be better throughout), and maple cross pieces. It would be great if you could share your Mathematica program as a stand-alone app; don’t know if that’s possible.Here is a link to a movie clip showing the vibration/flexing, both in real time and slo-mo. https://youtu.be/TZGwNO5fTgAIt’s hard to avoid vibration, and it becomes worse for longer cuts and smaller (tighter) pitch. The dowel in the movie is 22mm by 30mm with a pitch of 1.5 inches (Yes, I know, I’m mixing units!), being cut along its center axis. It turned out ok despite the flexing. If you try to dampen the vibration with you fingers you probably make things worse by deviating the cut, and the pieces will not unscrew. So I ignore the vibration. Some cuts have very little vibration, it depends on the wood and wood grain, the lamination, the pitch, and the diameter and offset from center. And sometimes things fail.

You could apply all the suggestions you made in the design of the cutting jig. Cutting a 2 inch diameter dowel may be beyond the scroll saw capability; on the other hand if you had a hollow core like you are suggesting that might work. You would have to think about how to mount the two ends securely. You will still run into problems with vibration/flexing. Essentially you are cutting a ‘spring’ that likes to flex.The best support for a round dowel is a long board with a v-groove. Mount that board between the scroll saw table and the dowel. Obviously, that will not work for square dowels.If you construct a table leg with a metal rod in the center you can stack a bunch of 5” to 10” spiral sections around it to achieve the length you want; the joints would be pretty...see more »You could apply all the suggestions you made in the design of the cutting jig. Cutting a 2 inch diameter dowel may be beyond the scroll saw capability; on the other hand if you had a hollow core like you are suggesting that might work. You would have to think about how to mount the two ends securely. You will still run into problems with vibration/flexing. Essentially you are cutting a ‘spring’ that likes to flex.The best support for a round dowel is a long board with a v-groove. Mount that board between the scroll saw table and the dowel. Obviously, that will not work for square dowels.If you construct a table leg with a metal rod in the center you can stack a bunch of 5” to 10” spiral sections around it to achieve the length you want; the joints would be pretty much invisible. Let me know if you make any and how they turn out.

The motors are:Stepper Motor - 125 oz.in (200 steps/rev, 600mm Wire)Motor Drivers:Big Easy DriverArduino Uno Compatible:SparkFun RedBoard - Programmed with ArduinoAll from Sparkfun.

No, I have not tried that but I will. I have thought about using foam pipe insulation (tubes) to wrap around a square dowel to dampen vibrations while cutting. Will try that later.

Thanks Steve, your original work inspired me.

If you do that, would you get an inner and outer spiral, or just the inner one? Could you cut more than one spiral from the same dowel?

Unfortunately I don’t. It takes a bit of time to make each of these, from laminating the blank dowels, to cutting the spiral, to finishing. If I charged for my time at a reasonable hourly rate the finished spirals would be too expensive. Maybe I try to sell some on ETSY; I’ll let you know if I do.