Hey Folks!
I have a 6x12' router with a vacuum table. I do super long engraving cuts so it doesn't make sense to use the vacuum hold down (and have the vacuum on for 20+ hrs) so I usually just screw down. I'm not getting great Z accuracy because I'm using a spoilboard that's meant for vacuum use and only has screws around the outside, but lifts slightly from the vacuum table in the middle.
I'm doing a full overhaul of my spoilboard situation and am looking for a couple of tips.
First, is there a recommended distance between screws when using an MDF spoilboard? My current design has screws roughly every 24 inches, with a maximum distance between screws of 30 inches (so each of the 4x6' sections has 4 screws on each outside edge, then 4 screws through the middle area at that spacing). Would you think 24-32 inches between screws is ok for keeping Z tolerances tight-ish? Is there some sort of spec on this for MDF?
Second, I plan to use counter sunk nylon screws on the middle work surfaces anchored by steel or brass threaded inserts. Are there any pro-tips for that sort of practice or is it pretty much straight forward?
Any other pro-tips or wisdom for running this sort of "screw it down" setup (no T-track or bolted fixtures)?
Thanks tons all.