Articulated sanding arm

[Reed Gray]

Another invention, but I can't figure it out...

https://www.youtube.com/watch?v=dnhd...#gpluscomments

robo hippy

[John K Jordan]

Another invention, but I can't figure it out...

https://www.youtube.com/watch?v=dnhd...#gpluscomments
robo hippy

I like the large bearing surface of the pivot on the lower arm, especially since it's made out of wood. Is the problem too much friction, or do you want smoother pivoting? Is so, a thin washer made from HDPE or something might help. Or are you looking for engineering ideas to produce these to sell? Want less play? Something else?

I can imagine that bearings that allow the arm to move too freely could be a hazard to the guy who turned the lathe on then let the arm swing into the work. A positive lock could help with this, saw with the type of locking lever typically used to lock the tool rest in place, tightened from below.

That's a great idea - I need one when using a rotary carver for long stretches. I've been resting my arm on a tool rest which is not ideal. I may make one, probably welded steel.

Do you find yourself adjusting the height often when sanding? If not, a collar locked to the tool post with a set screw could set the height. The sphere jig I have uses this method.

JKJ

[Reed Gray]

This is some thing I am not going to make. I do want the arm to swing more freely, kind of like the articulated hollowing set ups, but they are not heavy duty enough. I do have some thin plastic from milk jugs in between the surfaces which helps, but just can't see how to make it better. If some one else can make a better one, I would buy it.

I never adjust the height, and I based it on where I hold the drill when I sand. I do change where the disc hits the wood to get different scratch patterns, like 3 o'clock and 9 o'clock on the outside. I never have the lathe speed over about 50 rpm when sanding, in part because my bowls are warped.

It really does make a difference in production sanding...

robo hippy

[Eugene Dixon]

Maybe I can make an engineering senior design capstone project out of it. Not sure there is enough design hours in it, but I can get some opinions. Would you release the IP? You can PM me at dixone@ecu.edu

[Reed Gray]

Eugene, I have no idea what an IP is.... I don't want to make it, I just want a better one. If some one makes a better one, I may buy one. My current inventions take too much of my play time in the shop away from me....

robo hippy

[Eugene Dixon]

Intellectual Property. I can't put students on it without an IP understanding. You can keep it or you can give it to the university. We can work that out. We ask for a small donation for capstone projects unless IP is released to the university. PM if you want to pursue this.

Gene Dixon, PhD, MBA, PEM
ASEE Industrial Engineering Division Program Chair
Associate Professor
East Carolina University
College of Engineering and Technology
Department of Engineering
Slay 205
Greenville NC 27858-4353

[John K Jordan]

Then for a one-off, I would probably think about machining a long shaft for the tool rest and short shaft with a bearing for the lower arm, and use bearings at both pivots as described elsewhere. I would personally like a way to adjust the tension between free and lock. I might build part of it from steel for the ease of welding and part from aluminum for the weight. Maybe, all steel would be easier for me to make since I haven't welded any aluminum. I also have large sheets of 1" thick HDPE that might make nice arms. Have to think about that too.

I don't do much power sanding (occasionally use the Grex pneumatic ROS) but I could use one of these myself for sanding, carving, and perhaps other embellishment such as burning. Arm support for air brushing? I need to make one (after the planting season!)

If you don't plan to make these for sale please follow up for your fan base (which includes me!) with other ideas and modifications you try. I'll do the same, but it probably won't be before July/Aug. If you need some parts machined or welded then I'd be glad to help.

JKJ

This is some thing I am not going to make. I do want the arm to swing more freely, kind of like the articulated hollowing set ups, but they are not heavy duty enough. I do have some thin plastic from milk jugs in between the surfaces which helps, but just can't see how to make it better. If some one else can make a better one, I would buy it.
I never adjust the height, and I based it on where I hold the drill when I sand. I do change where the disc hits the wood to get different scratch patterns, like 3 o'clock and 9 o'clock on the outside. I never have the lathe speed over about 50 rpm when sanding, in part because my bowls are warped.

[Reed Gray]

Eugene, you can help yourself to the arm, I am not going to do anything with it. Considering the number of turners out there, some one should be able to new and improve what I have done...

John, some interesting ideas. I have 1 inch post material, and a few friends who can weld. I would like to maybe make it a DIY project for any one to do that is fairly simple...

robo hippy

[Marvin Hasenak]

I made one similar to that but I used a thrust bearing at the bottom of the hold that the arm's shaft sits on. The shaft was 1/2" and at the top of the shaft hole I inset a 1/2" bearing. It was over kill, the arm would spin like a propeller when hit. I used mine to set my forearm on to do stippling on duck calls.

[Eugene Dixon]

Thanks. I'll noodle on it and see what happens. I always need projects for senior engineering students.
Best,
Gene

[Hayes Rutherford]

Reed, why not just hang a platform from the ceiling with a cable you could adjust? Some turners already have pulley systems for living heavy blanks.