Hello, new Shapeoko Pro user here. I have the Bitzero V2 as well as the Bitrunner(probably irrelevant for this topic).
I’ve run 5 total successful cutting operations using all the accessories up until this point.
At the beginning of the failed operation, the bit plunged way below the workpiece, which was about .3” lower than was programmed. I’ve confirmed that the file was correctly setup, because I ran the same exact file again without issue.
Here’s the order of steps before the failure happened:
Initialized machine
Changed tool to “vee bit”
Jogged machine(skipped the measure tool prompt, assuming the next steps would make it redundant) over to Bitzero position
Began Bitzero probe operation which appeared successful(x, y and z)
Started job
Tool was kept the same(vee bit)
The machine appeared to successively measured the tool over the Bitsetter
The router turned on and began the job, then immediately plunged well below the targeted depth, by over .25”
I immediately stopped the operation, and re initialized the machine, re did all previous steps, with the exception of one thing: when Carbide Motion prompts to measure the tool before jogging, I allowed it to do so. This time, the whole operation was successful.
So even though the Bitzero appeared to successfully measure the workpiece zeros, and the Bitsetter measured the tool at the beginning of the job, I don’t understand where I went wrong the first time. The only difference is that the second time I allowed Carbide Motion to measure the tool before jogging to the Bitzero position. Is that really where things went wrong, or can this be chalked up to a simple software glitch?
As a new CNC user this makes me a bit paranoid about using the machine until I figure out why this happened. Any suggestions would be appreciated!
If you manually swapped for the Vee bit after using a different tool during machine initialization, without using the Change tool button, then this may well be why you had a inconsistent Z measurement.
The process that the BitSetter supports (i.e. automatically adjusting for tool length differences) only works if you always, always either follow the tool change prompts OR tell CM you are changing the tool (using the tool change button). If you swap the tool without telling CM, it will throw off its Z adjustment. You may think that re-measuring on job start will take care of that, but in your scenario you zeroed with a tool that CM still thought was the one you used during initialization, so the relative “Z zero information compensated by tool length” is off. The 100% reliable way is to always follow/use the user interface. Admittedly, it’s easy to forget that rule and swap the tool without thinking twice.
Yes I suppose I was getting a bit bold when I assumed I knew better than the on screen prompts.
So the thing to take away here is always allow the tool to be measured by the Bitsetter before zeroing with the Bitzero
I’m a new CNC user but definitely not new to woodworking, so my habit of reducing unnecessary steps wherever I can is apparently making its way over to the CNC world, a little too soon
Just a reminder. For X Y and Z measurement with the BitZero 1 or 2 there is a lip on the bottom. That lip is to go over the corner for X Y and Z measurement. If only doing Z then the lip sits on top of the material. If you forget the offset is about .3" if you did not have the lip over the edge for a X Y and Z. Internally when you select the Z only an offset is calculated to compensate for the lip being set on top of the material instead of being over the edge.
Further the BitZero does not actually measure the bit. In a way it does but it only calculates the delta between the last time you physically set zero with the BitZero or manually and compensates for that delta. So when you last set zero which may have the last time you used the machine that is persistent over power cycles. So if running a new job with a different material thickness that last zero is remembered. When you use BitZero a new Z zero is established and the difference between that last set zero is what is actually being measured with a new bit (when prompted by software or asking for changing tool in software interface) on a multi bit job.
So when you initialize and are asked to insert a bit you can but in any bit you want but the BitSetter is calculating the last zero and the position of the new bit preserving the last set Z zero.
