Video: Precision with an Avid CNC Build
Video link: Ep3: Avid CNC Build Getting Precision and Accuracy
Precision and accuracy are really important to a CNC machine. I wanted mine to accurately flatten a piece of wood down the entire length of the table.
I took a lot of time to level my base table surface, that is the part with the aluminum extrusions that the spoilboard sits on. I used an Accusize precision machinist level – https://amzn.to/3oa3THl. I followed Avid’s build directions and built the CNC gantry on top of the base surface. I then thought about it for a bit, and realized the machine’s precision is entirely controlled on how well the linear rails are aligned. The base table surface has almost no effect on precision. The gantry rides on the rails, and if the rails are not level then the gantry wouldn’t be level. Now, level doesn’t really matter, they simply have to be co-planer, but it is easier to get everything co-planer by using a level. Well, level does matter somewhat; it is why a machinist will level their heavy knee mill table, or lathe as gravity can sometimes affect the cut when the piece isn’t level, but we’ll ignore that for a CNC woodworking router.
I was a bit shocked to realize my linear rails were not at all level. Check out the video for a good explanation of why, but the reason is due to the alignment jigs that Avid uses to setup the rails. I made up my own solution for how to make it precise and accurate. It took some time, but I think it was worth it!
