Update Jan 27 2026: SmartLathe actually reached out with a video explaining the error!

https://youtu.be/xt2YxyMm-9o?si=9Pzs_nT3yTXxRuTo

Like I said, I have no financial incentive to say nice things about SmartLathe, but they have been genuinely amazing clearing this up and getting all the documentation updated. 10/10 dudes

I've done manufacturing for 30+, that all looked perfectly normal to me. You learn so much ripping machines apart like that. A few years from now you're going to know that machine so well. Nothing but respect for you.

120 vs 50 was steps per second.  120 steps per second is easy for the servo alone, but with the weight of the tools and the head combined on the servo, it was too much so if it moved 200 steps, when it tried to stop, the encoder noticed the step count was 203 instead of 200.  Manufacturers will program CNC for max speed to inflate their numbers, however when you load in tools, it becomes heavy.   The inertia of the rotating mass pushes the stepper a couple more steps and the encoder noticed it and errors the machine.  You inadvertently found the fix.  Next load your heaviest tooling into it, then have it rotate the maximum amounts between tools.  Next adjust up the speed of tool change, then once it errors, back it up a bit.  Not to the first fastest change speed that works, but a little further. Cooling fluid has weight too and you want to account for that as well.  This will get you a good change speed without inertia pushing past the step of the stepper that is supposed to stop it.   I don't remember what it is called, but there might be a parameter in there to slow the speed several steps before stopping.  Changing that speed (likely a percentage) will still yield full speed spin, but buffer the stop by slowing down first.         I like your content and your business idea.  There's not a lot of CNC forums to ask questions on, but your machine is just a bulkier and heavier 3D printer, they are controlled the same. Steps of a motor vs time. Your problem was overrun of the stepper vs inertial weight.  Issue you have, is 3D printer people figured out how to make the machine rebound while your engineers did not.   If a path makes the tool push the tool spindle one step, the machine will error out instead of stepping back.   What this tells you is to watch your cut speed and depths, pressure against the tool can push the stepper motor past its holding power.  If you ever find this to be a problem, #1 increase holding power (voltage) to the stepper, but causes heating, #2 replace the stepper with a larger one.  Cheers, Beers and much success tipped your way!

I don't know how you got your skillset, but I have much respect. Your channel is fun and you are refreshing. I wish you all the success.

I don't know if this will help you with this issue on your machine, but we added a 4th axis to a 3 axis machining center, and if you were machining a quick feature, and tried to index to the next position too quickly, the 4th axis would throw an alarm and shut the machine down.
What ended up correcting the issue was, we added a pause line ( G4 U1.  ... ) after each index, and we never had another alarm.
You are a very sharp lady and have crazy good diagnostic talents.
All the best.

Please keep making videos. These are awesome. Honest, down to earth coolness

Excellent work, getting this all sorted out. We are proud of you with every step you are making

Probably got a dirty prox switch from shipping. Move it fast it alarms before it can make contact, at slow speed it can make contact. 20+ years on Okuma, Mazak, Makino and others, both mills and lathes. At my last job before retirement, I watched techs from Toyoda spend 2 days cleaning shipping crud off of 3 new 800mm mills.

It doesn't matter which one you buy they all have problems! You rock, you fixed it. We had techs come out, and even they had problems. You got this!

“I don’t know what any of these fucking errors mean.”

-most relatable engineering quote of all time😂 I’m dead

They are frustrating when they are broke down but it's really satisfying to figure out the problem and make them hum again!

this channel is full-fledged addickting ... I learn stuff watching your videos and then learn more from some of the incredibly detailed comments.

I have been a lathe and machine operator for 15 years. You will have issues forever. No matter what machine brand or type, production has always been a bear on all of them. You will learn a lot in this process.

We've had a similar issue with some of our lathes. Turret indexes super quick but when there're lots of tools mounted the turret would alarm out. We slowed down the index speed and it was fine

That was thrilling, who knew a machinist' life was so exciting.

You never cease to impress me! You are one smart cookie! Good luck with your endeavors!

Smart Lathe explained the problem and the solution on their video ! They have nothing but respect for Caylee  ! She is incredible !

Welcome to playing with CNC machinery. Watching this brought back anxiety from my days as a CNC machinist.

Caylee never give up persistance and observation is the name of the game, I retired at 68 after a life time of sorting out problems on all types of industrial machines,
only to called back repeatedly over the last 10 years, I am now retiring for good at 78. From what I have seen in your video
you are a natural you are where you were intended to be you will do well in life and be the happier for it I wish you every success in business and life you are a credit to your generation, good luck girl. Mike in Ireland.

Great video... now we get to see a few issues that come up & can appreciate your ability to overcome them. Now, I am more than ready to see why you named your successful business what you did! Good luck on your journey!