If I remember correctly I think the keyway was tapered. On james car we pulled it off with a wheel puller. we put back by aligning keyway and tapped it on with a rubber mallet. The thing is I don't remember if it was a moon key or semi tapered?

Where Are You From? bay area

Do You own a car built by Durant? 24 flint/1927 locomobile

It is a standard half moon key and the pulley is a straight tight fit into position.

Where Are You From? Texarkana, TX

Do You own a car built by Durant? Several

It is a half moon key. I guess that the tension of the belt would also prevent it from coming off. I will tap it back on and replace the belt. I hope to start it up this week for the first time in 46 yrs. I have followed the manual for timing, new plugs, wires, points, coil, etc. and excited to see if it will run. Thanks for the input. Will post as to how it goes.
Jim

Do You own a car built by Durant? D-40