Download Free 3D Model Pi-Pilot 3D Print Model

Summary
When you need mythological salvation, look for a “sky pilot.”
When you need salvation from a slightly-too-small inside diameter, look for a pi-pilot! (Pipe-pilot. Get it? Anyone?)
This is a guide to keep a spade bit from wandering and chattering while reaming a PVC pipe or fitting (or other soft material with an existing hole) to a larger size.
The included STL files may or may not work for you without adjustment. Your best bet would be to edit the .scad file and generate your own. If you need to fit something other than a 7/8-inch bit, you have no choice at the moment.
Print Settings
Printer Brand:
Prusa Printer:
i3 MK2S Rafts:
Doesn’t Matter Supports:
No Notes:
You would be well-advised to take exact measurements of the spade bit you intend to use, as they vary in dimensions between manufacturers.
I was able to print this without supports so required cleanup was minimal. I did have to do some sanding due to poor printer calibration.
I included a “slop factor” of 1.25 since my Prusa i3 is long overdue for recalibration. If your printer is spot-on, you might be able to set the slop_factor value to 1.
Post-Printing
Assembly is straightforward: Insert the bit into the guide body; snap the pilot section over the top, and start reaming!
When using this I found that a brand-new spade bit still tends to “grab” a bit, so be prepared for it. You might even try running the drill in reverse, although I have not. Drilling generates heat, and the PVC pipe will tend to soften. Lubricating with water while in use may be helpful though messy. The “results” photo is with an earlier iteration, but the principal is the same.