Any of you CNC project guys know of suppliers of these kinds of linear slide rails, or does everyone just shop China via Ebay etc? Not sure I have the terminology right. I'm interested in the kind like pic where the circular section guide rails are supported to underlying base (as opposed to cantilevered unsupported extending from end blocks). Not interested in motorized but do want the ballscrew/handle type feature. Any forums where stuff like this comes up new in case hairbrained idea doesn't pan out? Guessing 300mm size would be about right.