Thank you for these detailed responses. They track very well with my experience using a 4x8' CNCrouterparts machine. There are so many things acting against pre

Thank you for these detailed responses. They track very well with my experience using a 4x8' CNCrouterparts machine. There are so many things acting against precision that I spent my first year of CNC ownership finding out what was really practical. Inlays on machines with >.005" accuracy don't work. Guitar necks do NOT fit. Puzzle joints don't glue up. The sources of problems are endless, even in a rigid machine: 1. spindle runout. 2. bit diameter changes (its is labeled at .25", but its really .246 3. climb vs conventional milling yields different characteristics in different materials. 4. bit deflection in certain cutting actions (plunge, tight corners, etc) 5. bit wear during the job. 6. dust removal / chip recutting 7. lost steps 8. dust in the ways of the machine 9. linear motion system misalignment. 10. workpiece slippage/hold down. 11. material not being flat/level (especially with cheap plywood, which often varies in thickness by >.005")(try making accurate box joints with that...)(also, it is never flat, it always has some twist/warp because of the way the plys are cut out of the tree). This machine seems to be a great thing, and I very well may build one for an outdoor plasma cutter, but, I find the accuracy claims very difficult to believe. All of these sources of precision loss will effect the end result.