It's nice to use commonly available materials like SCH40 pipe, but finding bushings that fit is very hard. If you have access to a lathe, then making your own out of acetal plastic stock like Delrin is easy. Plastic bushings are actually superior to the old fashioned oilite bronze bushings for many low rpm applications. The sintered bronze actually requires a minimum rpm to cause the inherent capillary function to lubricate the bushing for long life.
The bushings pictured fit 1/2" SC40 pipe and have a 1" O.D. I started with nominal 1.25" O.D.rod (which was actually 1.255-1.258")
Here's the breakdown of tools and steps needed:
1. Bore your stock as deep as needed with a Forstner bit just below your intended ID.
2. Use a boring tool to get the desired ID. This is an odd little tool that will reach in and cut the side as it turns.
3. Turn down the outside to the desired OD. I left room for a little flange on mine when doing the second pass.
4. Use a cut-off tool to remove your new bushing from the stock.
With quick change bit holders, the process takes about 20 minutes for a small flange. Zeroing out the CNC axis with each tool change really helps take the guesswork out and speeds up the cuts, but does take some time and skill. A sharp tool is really important with the thin plastic walls, and chucking the material with the minimum amount necessary sticking out is important too.
I made it at TechShop!
Teachers! Did you use this instructable in your classroom?
Add a Teacher Note to share how you incorporated it into your lesson.