Z Zeros at 200mm

I am getting sooooooooo close that I can taste wood chips!!! :slight_smile:
But I am having a problem with a 200mm Z Axis problem. I am not Sure if its my SKR Pro? or if its Estlcam? or if its Repetier??? (Skip past all the junk until you get to my question. I wanted to make sure everyone knew what I have for a machine.)


Ok, so I am following all of the V1Engineering tutorials/forum pages/and any net info. I have a SKR Pro TMC2209 with the same steppers that V1 sells, on DOM pipe.
I have stock LowRider with endstops firmware, no changes. Endstops are connected with 3 wire endstop boards and hanging off the table. My settings are the ones I am following on the V1 site and I have the sweet V1 touch plate. Most important thing!!! I gave up trying to crimp my own wires!!! I bought extensions.






Question:
How do you change the Z Axis Height to not be 200mm when Zeroed? When I do a G28 x y z and Zero all my axis’s I get a X at 0, Y at 0, and Z at 200. My Lowrider can’t even do 200mm and it crashes into the table and pulls the sides off the table. (side note: I am going to have to buy new couplers as mine are turning into slinkies.) I tried moving my machine until the lead screws came out of the nuts (click click) but I can’t get it high enough for it to not crash into the table.
I did get it to work once when I was in the LCD settings and I zeroed the Z under advance or custom… Not sure who on V1 Forums wrote that. But as soon as I “restarted” the machine again, Z was at 200 on the LCD screen and on Repetiers move tab.

(Just to be clear! My machine is not at 200mm, it can’t ever get to 200mm as its not long enough. instead my machine is all over the place! where ever I unplug the power is where the new 0,0,200 will be when i plug it back in. Which means if the carriage is already touching the table when I unplug it, then it will try to go down 200 from there when I hit Play in Repetier.)

I am assuming this is a 3D printer thing. as my Prusa has a 210mm lead screw. However, I am working with as stock of a Lowrider as I can do!!!

My first goal is to get the “crown” image drawn. But its hard to do that when the sides are off the table.

Um, It just occurred to me that maybe it was meant to be 200mm off the table. So I can use the V1 touch plate to zero. However, I have the clamp biting the plate and it doesn’t do anything. (its not plugged into the Plus pin) same as picture in SKR Pro setup page. So maybe that not correct either.

I have a feeling this is a stupid setting that is super easy to change, But because I am so new to all these things I can’t find it.

Thank you all for your help!!!

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I just learned about this today from Jeffbe3 in another post. Reading between the lines, this 200 is an arbitrary number that is intended to be higher than your LowRider will go. When Homing up, your machine has no idea of your bit length, so it has no idea how far it is away from the spoil board. The whole purpose of Homing up is to square the Z axis. So in order to setup to cut your stock you can do one of two things, lower your router “by hand” (electronically) and then execute a G92 Z0 before beginning the cut, or you can use a touch plate to set the height. When probing downward on a LowRider, the G38.2 command is used.

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Yep. Robert has it right. You haven’t done anything wrong. The 200 comes from the default size of Z in Marlin. It homes up and assumes that is the top of the space. You don’t then zoom down to zero, you would jog to the surface and set zero using G92 (or one of the lcd options).

Interesting!
I have to say this really messes with my head!!!

Take 1
Connect to Repetier
xyz shows 0,0,200
load the file and click Play
(The LR2 then tries to go down 200 to get to 0 on Z. )
Cancel print and I wait a bit for it to quit… after its crashed into the table and does the next command. Then I move the z back up to the top.

Just so I am always doing the same steps, I disconnect and restart Repetier. ( I get weird values if i don’t, shown below in take 4-5)
Take 2
Connect to Repetier
xyz shows 0,0,200
load the file and type G38.2 z-1 (-1mm thickness of the touch plate) and Enter.
(Because i don’t have any tools attached, i just click the clamp to the touch pad to make the Z stop.
xyz shows 0,0,200
click Play
(The LR2 then tries to go down 200 to get to 0 on Z. )
Cancel print and I wait a bit for it to quit… after its crashed into the table and does the next command. Then I move the z back up to the top.

Take 3
everything is the same but this time after G38.2 z-1 I also do a G92 z0.
xyz Shows 0,0,200
click Play
Works!!! Z goes down 1mm which is the “z-1” in G38.2.
xyz shows ~,~,199
When its done it goes back to where it started.

Take 4
I didn’t restart or disconnect. Left all values where they were
xyz shows 0,0,200
click play
Works!!!
When its done it goes back to where it started.

Take 5
This time I left everything the same, didn’t disconnect or restart.
But I reloaded the file
xyz shows 0,0,0
click play
Works!!!
When its done it goes back to where it started.

Take 6
This time I do disconnect, restart and reconnect.
as expected everything is back to
xyz shows 0,0,200
type in commands g38.2 z-1 and g92 z0. otherwise crash.

Is this what you’re seeing too?
Thank you for showing me these commands.
Sadly, I assumed Robert was doing a G92 z0 OR G38.2 command. But a G92 z0 always needs to be done.
I haven’t tried homing yet. In the tutorial it says to find a place in the middle of your three axis so that you have room if something goes wrong. But it doesn’t matter, Z crashes every time I do not do a G92 z0 command.
I am curious about the LCD options???
Is there a way to just click a button and have the LR2 do all the typing for me?
Thank you

That is almost what I expect. The 200 in RH is annoying, but it isn’t what Marlin is thinking. You can probably learn a lot by sending M114 at various places to see what Marlin thinks the coordinates are. The trouble is that if M114 disagrees with the RH report, then any jogs from RH are going to not go where you expect.

You can set up some macro buttons for common scripts.

The one that doesn’t make sense is Take 2. I thought G38.2 did set the coordinates. I haven’t seen it with Z-1 though.

From https://marlinfw.org/docs/gcode/G038.html
it says the “z-1” or z-0 or z-200 is the distance away from bed or work surface… i think. I used a z-1 in my example above because the touch plate has a nice thickness to it. However, in practice it didn’t work as expected. ( I need to measure the real distance!) The first bit of material was a bit more than the lower layers.

I finally cut out something! WOOT!
I cut out a nice version of the router plate. My first one was hand cut from 3/4" pine. it allowed for my Bit to stick out 11mm from bottom of the router plate. I have a ton of Ikea junk boards all around and they are all about 20mm-3/4" thick! Then I spotted some junk laminate flooring… Oh this stuff is 12mm thick!
As you could guess I had to cut the rest by hand! But now I have a nice 20mm of cutting space! Time to cut the sides out of flooring tonight!

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