Longmill Journey - New User - lessons learned so far

I just successfully finished my first extended job (10+ hours). Thought I would put together a compilation of lessons I have learned since getting my Longmill, mid October 2020. Most of these lessons are from this forum (Thank you all). I wish I had bookmarked where I found each item to make your journey easier. If you have issues, read, and post questions, someone WILL help. Once you learn, pass it on.

Take your time. Check and double check your assembly.
After assembly, on first cuts, I found that the y rails were off by 3/16 front to back. I took the machine off of the waste board and realigned. Now within <1/16”, side to side and diagonally.
Tight but not too tight.
I was having trouble maintaining the xy position between tool changes. Troubleshooting led me back to the forum. Based on suggestions I loosened my anti-backlash blocks, adjusted the v-wheel tension. I ran the machine back and forth, full on all axis. With y full back, both sides. I tightened the blocks and set the adjustment screws finger tight.

XY axis off after tool change
I was still having occasional issues maintaining xy on tool change. Back to the forum. One post mentioned that both wrenches should be used to change the bit. Yep, I was using the button on the router and one wrench, moving the xy slightly.

Another post suggested using $1=255 grbl setting to keep the stepper motors enabled. I set up 2 macros, one to lock ($1=255), another to unlock ($1=100). No more xy shifts.

Check your power.
I would get into a cut and the controller would “blip”, stopping the job. I first thought there was an issue with the controller. Not. I have an older home. The one outlet in the shop was flakey. I took this opportunity to run two new lines, on separate breakers. No more issue.

As of now, my standard setup for a job

  1. Clamp down material.
  2. Run y all the way back, both sides full back.
  3. Lock axis ($1-255)
  4. Set job zeros.
  5. Run job, only reset z zero on tool change (leave xy alone and use both wrenches)
  6. After all cuts complete - Unlock axis ($1=100)
  7. Run y back full for next job.
  8. Clean up machine and area.

So far the cuts are near perfect. I have much more to learn!

I hope this helps someone.


Great info, thanks for sharing.

It sounds like you don’t have homing switches, have you considered homing/limit switches? I intend to post some photos in the next week or so when I finish my Z down portion.

I looked at the info on Homing / limit switches. Sounds like a nice addition.

I don’t think they would have helped much for my original xy shift which I was causing during tool change. If I understand the info correctly I would need to re-home at each tool change since the amount of shift would be unknown.

I may look into this upgrade later. For now, making sure the y is straight and locking the all axis has been working perfectly.

Thanks for for the suggestion.

No need to rehome at tool changes. If your machine is tight and operating normally all you need to do at each tool change is reset your Z0 height to adjust for the new cutter length.

You only home when you first power on for the day or when the machine crashes.

Or, if you suspect there has been a positioning problem due to some other error or observation - but this shouldn’t normally happen.

Essentially once you set your machine position to 0,0,0 everything else is an offset of that in your work. If the machine isn’t losing step or coming out of alignment, the machine coordinate system should be stable and you can go about setting work zero for each workpiece and running your files.

I think you’ll find having the sensors in place helps give you confidence the machine is cutting where it is supposed to. It is easy to bark at shadows if you aren’t homing the machine at the start of the day.


Thanks for the info. I need to read up on this more so I can fully understand the setup. Any good resource references would be appreciated. I have the you tube video posted elsewhere in the forum but haven’t had time to view it yet.

Adding switches are on my 2021 to do list.