This is a tool for aligning wooden rings made by a "Ring Master Lathe" to make sure that they are centered when you glue the rings together. The Ring Master Lathe allows you to create a bowl from a 1" thick board that is a 12" circle.
As you turn the two pieces of 1/4" MDF, the acrylic washers / bolts move in and out from the center of the device.
To see it work, click here: https://www.youtube.com/watch?v=y1Si49jzygg
You could also use this to make an iris if you wanted to do so.
Step 1: Laser Cut Two Pieces of 1/4" MDF
Start by cutting two of the attached DXF out of a sheet of 1/4" MDF -- I used a TroTech Laser at Tech Shop.
Step 2: Cut Washers Out of 1/4" Acrylic
Take a scrap piece of 1/4" acrylic and cut out 24 washers with 3/8" holes in the center (I.D.) and 3/4" (O.D.) This was also cut using the TroTech Laser.
I bought eight (8) 1 1/4" bolts and nuts from Home Depot.
Step 3: Bolt the Two MDF Rings Together
Insert the bolts with one acrylic washer on bolt side and two on the nut side. Once you are sure it works, replace the nuts with nuts that contain nylon inserts.
You need to have a nut that will lock at a specific point and not prevent the two disks from rotating.
I made it at Tech Shop.