This a super easy, quick build of a Polargraph (hanging drawing robot) gondola. I built myself a polargraph and quickly realized, if one wanted to build one at home, they would need a 3D printer to build one. I saw a similar version on the net and decided to scratch build one and write an Instructable about it.

Step 1: Gather and Prepare Parts

A quick trip to you local parts store and a few toonies should get you going. Heck, if your dad has a well stocked garage, he might have the parts you need right at home!

You will need:

2 x 6203 bearings
1 x 3/8" hex brass nipple
Compact disc
2 x 3/8" x 15" tie wraps
A few large nuts for weights (as required)

To get these parts ready is a simple task. You want the bearings to have the least amount of friction possible. If they come with shields, like these ones did, you simply pry them off with a screwdriver. Then you can rinse out factory grease with varsol or brake clean (ask Dad for help if you need).

Step 2: Build

Here goes, you take the nipple insert it in the center of the two bearings. You can squeeze them in a vise, or tap them with a hammer to lock them together. Then you wrap the tie wraps around the bearing faces. Here you can trim them to about 6" long from the face of the bearing. Then you will need to get a hot glue gun and stick this whole assembly on a compact disc. Make sure when you do this, you don't press down on bearings too much. You need a tiny gap between the bearing face and CD. If your gondola has a servo for pen lifting, like mine, glue it on to bottom of CD while the glue gun is out.

And you're done!

My PG build uses GT2 timing belts, So I just glued the tie wraps to the belt ends. I ended up needing a few weights to keep it vertical on the drawing board. I glued on some bearing collars I had in my tool trunk, but you can use some large nuts.

A Sharpie marker fits snugly in center brass bushing. If you have too, shim with a small piece of cardboard. You could always get the nipple drilled and tapped on one of the nut faces and install a set screw if you wanted to get all fancy! I prefer the cardboard shim method.

Step 3: Test

I use this gondola on the Polargraph printer I built. It basically draws JPG, SVG and DXF files via CNC and gcode, on a large surface. People have these mounted on walls and windows and print as large as the belt length will allow. Here is the first print off the PG with the new gondola.