Or the pit, as is the case tonight. I just finished roughing in the turntable pit, which I ultimately decided should be concrete, not wood.
The key dimension on the turntable pit is the elevation of the pit rail. Sure I’d like the pit itself to be perfectly round, but as long as it doesn’t wander too far, and is pretty close to the precise dimension where the tracks cross onto the bridge, it actually doesn’t matter too much if it’s perfect. The height of the pit rail, relative to the tracks, however, does need to be accurate otherwise we’ll have binding and flexing and all sorts of challenges.
So, I got out one of my favourite tools – my router – and began excavating the piece of MDF that I had cut to fill the original hole. I sneaked up on the proper depth over a number of passes, then slowly worked out to the line that was the wall. Then I excavated the inside of the pit, including the edge of the pit rail shelf in a number of concentric circles to make a basis for the sloping ground of the pit.
I left the middle intact so the router wouldn’t fall into the pit. Notice how the last passes are a little ragged; I think the MDF was eating my router bit. Once I was kind of happy with the general shape, I sanded it roughly by hand, and took out the central pillar.
There is dust everywhere! I am happy to have the ventilator off, but now I need to have a shower before I turn in for the night!