Frustrated rookie

Just finished a 5 hr. rough carve on a two stage project. While installing the finish bit, I noticed that the spindle moved slightly. When I started the finish carve, I selected “use last zero point”. I obviously was wrong to think that this would take care of the slight movement in the spindle. The “slight” move resulted in a wasted 5 hour carve. My question is…what should I have done to reset the start point for the second carve? I have found that it is difficult to change from a wide straight bit to a pointed v bit and arrive at the same zero point. Suggestions appreciated.

Please disregard the photo included in my request. It is not relative to my current problem. Sorry.

If you do this:

Then your Steppers will hold position anytime the machine is powered on. This will hold position adequately during the bit swap and simply selecting “use last” for the X,Y will work fine You’ll just have to probe Z for the new bit.

IF you do this but you really got onto the collet nut, and think it lost position anyway, then you can re-home and before going through the probing and “use last” . . . the re-homing will eliminate any of the movement or slippage that may have occurred.

That said, there is a whole different, more complicated method that inventables suggests here: But IMO their instructions lack clarity and are hard to follow AND the above method works better anyway.

Thanks Seth…I had already set the switches to off and my #1 code is set to 255. The spindle still moves rather easily. You are confirming my belief that selecting the “use previous zero position” should correct any issues with spindle movement during bit change. Not sure what went wrong this time.

hmm, well it could have skipped a tooth on the belt if they are too loose :man_shrugging:

like that cryptic instruction guide indicates, they suggest hoping after the bit swap. so that would re-set the position properly and should fix your current issue.

On a bit swap just to clarify ( i’m a rookie too )
Is it preferred to

  1. Home the machine, probe Z, set XY - carve … Swap bit, Home Machine, probe Z, use last XY then carve
    Or 2. Home the machine, probe Z, set XY - carve … Swap bit, Probe Z, set XY ( confident that it didn’t move) then carve
    Or 3. Home the machine, probe Z, set XY - carve … Swap bit, Probe Z, use last XY then carve
    I’ve made the mistake of not homing and it was not good.
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Well, technically those are all wrong based on the latest email exchange I had with support this prior week…
However #1 does work 99.99% of the time , just don’t put a drill operation at 0,0 and you’ll be fine.

IF you have a drill at 0,0 then you MUST move the cnc back to work zeros before starting the carve or it’ll just plunge that drill wherever the machine is located when you hit go… (at least, that is the case until the big gets fixed)

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