Bump Stop, Homing, G28, and Triquetra Workflow and Speed

Still not a bad idea, if you’re not using G28 for something else, to set that at your bump stop corner. That way, if you ever change your XY zero, you can just G28 to get it back.

I definitely want to keep G28 for my bump stop fall back. If I need set a new X 0 Y 0 will G10 L20 P1 X0 Y0 be reset or cause a problem. I am not that familiar with G code. Thanks

G10L20 P1 X0Y0 is what sets your zero.
Easel sends the same command when you set zero.

Thank you very much.

I am very new and have never entered things manually in my machine, but I am thinking I may need to start learning. I have the Triquetra. I have a few questions.

  1. What is a Bump Stop.
  2. How do you open the program to enter G28?
  3. What happens if I do all of this and I bumped my machine during a two stage carve?
  4. If you home your machine after using the Triquetra set up, does the information from the Triquetra disappear?
  1. Bump Stops come in several types, but you can think of them just as it sounds. It is basically something that you can bump the material up to that is repeatable. This could be for a single axis or you can have an X/Y Zero Bump Stop.

  2. Go to the menu option: Machine>Advanced>Machine Inspector
    The Console TextBox is where you issue commands to GRBL manually.
    Check out this thread for G28 information …

  3. Make sure that you have your Dip Switches inside the controller set correctly if you have an X-Controller. This forces the hardware to provide full holding current to the motors while they are idle.
    Also, set $1=255. This tells GRBL to provide full holding torque while the motors are idle.
    Also, make sure the pot for each axis is adjusted correctly. These are meant to trim the current. Adding too much will makes the motors hot and potentially burn out the driver and removing too much will make the motors under-powered. There is a sweet-spot and I think most are shipped in the sweet-spot.

Here is an image of the Dip Switches…

After doing this, if you still move the axis during a bit change all you have to do is re-Home the machine which resets the machine (X, Y) Zero; Work (X, Y) Zero is just an offset from that and you should not have to mess with that. You should then probe the Z-Axis to set the new bit.

As a note, if you are milling the same part many times and need to power the machine down at the end of the day, but need to start again the next morning all you would have to do it re-Home the machine as long as the parts are placed right where you set the Work (X, Y) Zero (… enter the Bump Stop …). And, if you did not change the bit then the Z-Axis would not need to be reset either.

  1. As long as nothing is loose then it should not affect anything (see above discussion). Homing the machine sets the Machine (X, Y, Z) “Home” positions while using the Triquetra sets the Work (X, Y, Z) Zero positions which are stored as offsets from the Machine Home positions. As long as the nothing changes in the relation between the machine and work-piece then it should not make a difference.

I hope that answers a few of your questions, or it at least provides you a place to start.


Brandon Parker


2 - A prerequisie for using G28 is performing a homing cycle prior. I do this each time I power-up the machine.
3 - You re-home :slight_smile:

To home in Easel open Easel Machine Inspector and send $H in the Console window. Type $H and press Enter

Homing syncronize machine space to model enviroment.
This allow for instance consistent work zero and G30