I needed a linear table/macro slider and I was about to buy one when I realized that I could design and make my own.. Perhaps not that much cheaper but a lot more fun than buying one :)It's a simple design with not that many parts (see complete BOM under instructions) I wanted to use parts that are easy to get and that are inexpensive so i went with cheap China bearings/rails and ordinary threaded rod and el cheapo nuts and screws, all bought on eBay.You get 45mm of travel and each turn of the knob equals approx 0.8mm of movement. You can use a finer threaded rod and get even higer resolution but I think 0.8mm/turn is ok in most cases. It sure beats trying to move the tripod back and forth a few mm..The parts turn out quite good on my machine but there might be some fine trimming needed to fit the cover properly. The carriage and thread cover are designed to be printed standing up, but you are free to print them in any orientation you want :)