Posted By: George Haycraft,Picnic Cat #29, Melonseed #253 arl, I did something similar with my Picnic Cat. I made the treads from 1 1/2 x 1 1/4 fence ballisters made from the  recycled plastic decking from Lowe's. I passed the steps at an angle over the table saw to create a half parabolic  channel, which I then gouged to half round with a piece of rigid copper pipe filed flat across the ends. I drilled the end  holes similar to yours. I fastened mine with flathead SS bolts and nylon insert lock nuts and washers. The treads  practically snap into place without the screws. C  108