I don't know what part you need from Thompson but your best bet is to keep an eye on Ebay. I built my machine based on what I could find on Ebay which is kind of backwards but it was the best way to go cost-wise. If you design a machine first, then your stuck trying to find parts that fit. I found Some Thompson 1" round supported rail, 2 pieces 48" long and Thompson 1" dual pillow blocks (the long ones) all for less than 300.00. Your might have to adapt the design you have for a different linear system or you will get stuck with the cost of plan-specific parts. Keep your eye on Ebay, that is your best bet to keep cost down.