Well, the third curve did work better than the first 2, but I still have a problem that the wood expands more than I am expecting and so I don’t end up with a 90 degree curve even with my extra half inch pull in on each end. The problem appears to be that the last 12 inches of the wood wants to be straight rather than continuing the curve and I have not been able to overcome the strength of the wood to stop this. So, I turned my work table around and created a new jig for the curve. The new jig is still using a 2.5 foot curve, but is moved inward on the corner by 6 inches on both sides. This causes the curve to be 6 inches longer on each end but beyond the 90 degree end that I previously used. Hopefully I will end up with a full 90 degree curve with a smooth transition on the ends. I am out of 1/4 inch stock so I will have to wait till Thursday night to actually test the new jig. Here is the new jig:
You may be able to see in the picture that there are lines drawn at every 15 degree mark. This will be the point where I put in a cross member for support and is also where I put the pegs. In the first two jigs I just approximated where I wanted to put pegs and ended up with some flat spots in the curve because the spacing was to long between pegs. So, this time around, I am making the jig very regular. Also note that I put dowels in at every 7.5 degrees in for the first 30 degrees to give extra strength to the curve on the ends.
I can still use the first two curves that I produced as they are equal offsets meaning that if I reverse them and attach at the ends, they will exactly offset the shortcomings of the curve so that I can go around something like the stairs.
At the end of the day, I also did the first pass on every railroad tie. Each little 3/8×3/8×5.5 tie has to be routed 1/8 of an inch to fit over the beam and give added control to the spacing of the beams that support the track. This has the advantage that it aligns the ties and provides a better surface to glue the ties to the rails. I still have to make a second pass because the largest router bit I was able to buy is 3/4 inch wide and I need 1/16 inch more to fit over the beam width. Ugh. So, I made a jig for the ties that holds them in place for a pass over the router head, then I flip the tie around and do the same thing. After finishing all of the ties, I then adjust the jig to move over 1/16 of an inch and repeat the process with ever tie. I have 3000 of these little ties to do this to and the Poplar wood splinters on the edges. So, after doing the second pass, I still have to sand the little ties down so that they don’t have feathered edges.