[Arjay]

It would be an interesting exercise to have everyone load a given set of G code for a square or whatever and have them cut it on their machine. Measure the end result and publish the results.

Even better - have the part sent out to the same lab for measurement.

[Goemon]

It would be an interesting exercise to have everyone load a given set of G code for a square or whatever and have them cut it on their machine. Measure the end result and publish the results.

Given the complexity in the factors that contribute towards accuracy (or inaccuracy), I doubt such a test would tell us anything conclusive. Even if everyone was cutting the same wood from the same batch with the same water content and using the same end mills, the different climates would alter the results.

If tests were limited to aluminum, some routers might not be sufficiently stiff or have decent enough vibration damping which would throw off the results. A machine could be accurate for one job but not the next.

Plus, we'd still have the main issue which is measuring it consistently from one user to the next. The machine builder is hardly an impartial judge and the results with cheap ebay calipers and gauges can be manipulated. I struggle to get the same results if I measure the same part twice with my calipers. And forget about those cheap ebay gauge arms. A stiff sneeze changes the reading with those things. And... People lie on the internet.

Measuring cnc accuracy is like taking a selfie. We can all take a good one with the right lighting but our friends camera then adds 10lb...