The can of worms has been mostly sealed and the mast step is back in the boat. I ended up replacing everything including the plate, riser, shoe, and fasteners. Just like every other project on the boat, I underestimated the amount of work, time, and cost of this "while you're at it" project. Ultimately, I'm really happy with how it turned out and I don't' think I'll have to worry about the step again.
I thought I was going to be able to drill all the holes and machine the bevel on the plate myself with my table top drill press and router table. I tried beveling the edge of the original 6061 plate, but my bit just chattered and made a horrible noise regardless of the feed rate I used. If I wasn't able to bevel 6061, the new 7075 plate was going to be a no-go. I found another local machine shop that had some time and was excited to help out. They were reasonably priced and had a good working relationship with a local metal finishing shop. The machine shop warned me that the plater could take up to 2 weeks to finish the plate, but they ended up turning it around in 2 days after the machine work was done. Having it professionally done turned out to be the right decision because all 12 holes lined up perfectly with the original holes in the TAFG.
The spacer was a little more challenging. I thought I would be efficient and purchase a 2" piece of G10, but quickly realized that was a poor decision when I placed it next to my template routing bit and it was 1/4" too short. I called around to a few fabrication shops and none of them wanted anything to do with G10. Even the boat yard I'm working at didn't want to use their equipment. I ended up buying a few carbide blades for my reciprocating saw and hacking away at it until it was close to the desired shape. I then attached to original shoe and finished the edge on a table top belt sander. It created a massive mess that was only slightly mitigated with my dust extractor. Fortunately, I did it outside and wore a mask. G10 is amazing stuff, but working with it is a major pain in the ass.
the shoe was only 3/4" thick, so I was able to rough cut it with a carbide blade made for Hardie siding in my jig saw then template route it on my router table. The result was an almost perfect match to the original shoe. It did require a little bit of finish sanding to fit in the mast, but it only took about 10 minutes.
With all the pieces cut out and the holes drilled, I wanted to improve drainage to reduce the amount of water that flowed over the plate and under the cabin sole. The goal is to route water to a central hole in the plate where it can drip directly into the bilge. I used my 3D printer to create w router template that provided a 1 degree slope and laid out a pattern that should provide a path for the the water to find it's way to the middle hole.
At this point, the step looked great, but I really didn't' want the standard G10 color in the middle of the cabin, so I dyed the parts black with RIT DyeMore. It's far from perfect, but I don't think anyone's going to notice.
The final step was installing a coin. Up until I read this thread:
https://ericsonyachts.org/ie/threads/coin-under-the-mast.22004/#post-180830, I was just going to throw the coin in before the mast was stepped and allow it to float around. I used another 3d printed router template to route out a pocket, then filled the pocket with clear epoxy. We chose a Canadian toonie because we love the Canadian Gulf islands and my kinds think "toonie" is a funny name.
I ran into one hiccup when I was at the boat yesterday to do the final install. The drain hole ended up landing right on top of the new sistered G10 plate. Of course, I didn't have my Dremel and I really didn't want to remove the plate again, so I drilled a hole then used a multitool with a metal cutting blade to create a small notch in the top of the plate. again, not perfect, but it should do the trick.
With this project done, everything is ready to put the mast back in the boat next week.
