Concrete form for curves, bender board.

[machiningfool]

I mentioned before that I am designing a garden railroad. This layout has quite a few curves, all of which is the same radii, so this tool will permit me to accurately place the bender board for curves in the proper position. This tool is a fixed radius, but could be designed to be adjustable, this curve is 93 inches, which happens to be the inside curve for the foundation for the layout. The outside form will be laid after the inside one with simple 2x4's for symmetry. I am making the foundation or railbed 54 inches wide. The reason for the wide width is to accommodate the cement mixer and the hoist to lay the 195 lb. sections of viaduct for the layout. The pictures that I have today are of the bender board end. It allows me to clamp the bender board in the correct position so that I may drive stakes and screw the board to the stakes. I will have follow up pictures and explanations in the coming days. The center of the arc will have a height adjustment for the center of the circle. The height of it will be adjusted with a laser level. The other end will have a level to adjust the height of the board. Tomorrow I will make the adjustable jack for the board end and the center rotational attachment, so here is what I have done so far. The last picture is of the attach point for the center of the arc, you will see a better of that tomorrow. Bob.