Modat, here's a pic of what I used. Originally I had a single 2x3 steel tube, it had too much "slop" in it though, and was welded solid to the head with no way to adjust it. Most of this setup now came from a scrap yard, I'm pretty sure it used to pack Huggies into bags in another life. There are two 1" dia. steel rods, they slide in & out on linier motion pillow blocks, the square tube in the middle has a captive acme nut in it, a reversable AC motor & small gear drive runs it in & out. There are adjustments built in everywhere, in, out, up & down. I use guides from the C.I. Wright Co. - Buckeye Saw used to sell them. These are 15+ years old.
