I haven't had much time lately, but the 2.375" motor project is moving along. The 2.375" motor project...hmmm. I have never a given a motor or rocket project a name. I usually refer to them by color, some key feature, or size like the orange and black rocket, or the camera rocket, or the 2.375" motor. I think I'll try and come up with a name for this motor, maybe something from Norse mythology since the high L/D of the design makes me think of the motor of one of my favorite sounding rockets the Loki dart.
I should be ready for the first test firing which is tentatively scheduled for early December. I modified the one existing casting set-up that I had for the original 2.375" motor to accommodate the slightly smaller diameter casting tube size. That set-up worked well in the past. The t-handle is removed during casting so it doesn't get in the way. Once the propellant is cured the handle is used to unscrew the mandrel from the base which pushes it part way out out of the propellant segment making mandrel extraction pretty easy.
The other two are simple hardwood bases coated with epoxy to maintain dimensional stability and keep them from absorbing the grease which will be used to keep the propellant from sticking. The coring rods are Delrin, which I haven't used before. Apparently Delrins thermal expansion properties allows them to basically fall out of the propellant once fully cooled. Basically the coring rod takes longer to return to ambient temperature than the propellant allowing the rod to shrink a bit more than the propellant.