Aircraft Crankshaft Oil Seal Mandrel

This thing is a mandrel I printed to assist in stretching a one piece crankshaft oil seal over the propeller flange of a Lycoming O-235-L2C aircraft engine. It helps prevent snags and damage by helping the seal slip over the prop lugs and flange edge.

I printed this cone-faced side up, with supports. The support is for a rabbeted outside edge on the flat side that makes room for the recommended seal stretcher tool that rides on the prop flange edge (see picture).

I printed and used the SAE-1 version (4 3/8" diameter prop lug spacing) in PETG for my engine and it fit the bolt pattern fine. I adjusted the model's prop lug spacing to 4 3/4" diameter and saved it as an SAE-2 version, but I haven't confirmed the dimensions on an actual engine for that type of prop flange.

NOTE: Please verify compatibility of the material used with whatever lubricant you use to grease the seal during its use.