Usually, 3D filament rolls come with the one size in the middle. It's about a 4cm hole. However, after buying filament from another source, I notice the LARGE hole in the middle. When I put this on to the holder I made (see my previous instructable) the hole is too large for it to sit on the holder, instead sitting on the printer top and not rolling. What I needed was an adaptor. Do I 3D print one? Oh I couldn't as it won't roll. So a trip to the local hardware store (Bunnings in Australia) eventually provided me with an answer. I had one idea, and the wife found an easier way to do it. This is a simple 5 minute job.
Step 1: Get the Parts and Modify
In the irrigation aisle, there are 40mm couplers. In the plumbing section, we found a 40mm sewer floor connection with a flange.
These parts fit together nicely with a small bit of pipe glue. Cut most of the 40mm floor connection as shown, leaving a small collar.
You will need 1 coupler and 2 of the sewer connections. Sand back the edges so they can roll without catching.
Step 2: Glue Together
Glue the large end to the coupler as shown. Once both sides are done, paint.
Step 3: Finish
As you can see, the adaptor raises the height of the reel enough to clear the printer and roll nicely. Also, the flange on the sewer adaptor stops the roll from moving and falling off. This is a great companion for my 3D holder project.