T-Nut Milling Tool
Using T-Nuts to secure the propeller to the hub is Miniplane's solution to persistent false reports and rumors that the OEM supplied propeller mounting bolts are so weak that they might shear on some occasion. It is a ridiculous assertion unless the original bolts were exchanged for Wal-Mart grade kitchen fasteners – or something similar.
If needed, what follows are the instructions for those who chose to use these fasteners.
This is a short video on how to use the tool and a drawing with the milling specifications.
This tool is used to enlarge the stock holes in the hub and propeller so that 8mm T-nuts and bolts can be inserted. A T-Nut with a bolt is more resistant to shear failure than a simple nut and bolt.
You must have a drill press, depth gauge, and caliper to do this modification. For a modest charge, we can do the work, if desired. If so, please send all of the parts and the propeller and follow these instructions.
Incorrectly attaching the propeller, excessive run-out and/or out-of-track, damaged propellers, and propellers with incorrect mounting dimensions cause excessive vibration and may lead to bearing or engine mount failure. The center hole on the propeller must FIRMLY fit onto the hub projection. If it is not a tight fit, either the hub or the propeller is damaged, usually the latter. Upgrading to the super-strong T-Nuts is no substitute for not fixing existing problems with the propeller..
All parts and the T-Nut milling tool can be ordered from Miniplane-USA.