A Burke 116 arrived today with a propeller assembly height that corresponds to @dave's Burke 115 propeller height measurements (see images below).
The condition of the chair is overall OK, however, the most important previously unknown is that I'm able to confirm that the memory return mechanism works well with no detectable glitches. I accept this propeller mechanism for the project and will be able to paint the buckets and this propeller Tuesday. The cutting of one one of the Burke 116 buckets will be tomorrow.
The initial examination of the hardware leads me to reject it 100% as you can see in one of the photos. Even though I have reason to believe the hardware that came with this chair is not the original equipment, this level of mechanically inhibitive ferrous oxidation and the beginnings of orange colored surface oxidation in other Burke 116 chair seat hardware is a good reason to use ASTM qualified stainless steel hardware replacements. I was able to setup a rig to force remove one set of hardware for a closer look and treated the other three fastener assemblies with light machine oil for removal tomorrow. The weld nut appears to be original equipment, however the fastening screw is not a machine screw but a 1/4"-20 x 5/8" six-point bolt with a flathead screwdriver relief cut through the middle of the head and no countersunk shank underneath. Both pieces of hardware are magnetic. I assess the two weld nuts as original equipment based on identical measurements, but believe the four bolts and two square nuts are not. Once the propeller is removed from the chair bucket, I will be able to confirm suspicions about the hardware and take a straight line propeller assembly measurement.
The paint booth is completed and ready to go.
The delay is a test of patience. The two weld nuts that look to be replaced by a square nut is oxidized to the point that even with a set of locking pliers and full torque on a Skill multipurpose drill, the fasteners will not bust free. To wedge a screwdriver underneath the square nut in order to lock it in place for torquing the bolt free will likely damage the fiberglass and it will have to wait overnight for disassembly. I want to comment further on the replacement propeller assembly once I have it apart. Even though the propellers look quite similar at a glance, the contours of the lines give the propeller shapes a distinctive enough look that would be difficult to overcome with a spacer ring welded in.
At this time, I have enough equipment on-hand to commence building one TOS Burke 116 chair ready to receive two black cushions at end-state.
The plan is to remove the propeller assembly, take a set of precise measurements, then cut the fiberglass on one of the chairs on Monday and paint the replacement propeller along with the cut seat on Tuesday.