LR3 Kits Advice

I’m pretty sure it was pictures of your build plus Teaching Tech videos that made me think that was ‘default’

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Funny, I assumed that the TT videos were set up so that the camera position was viewing things from the front, same as he sets up his 3D printers, origin towards the camera, left of frame.

He sits/stands behind his printers, too.

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Correct. His camera is set up where ‘you’ would be standing in that pic I shared in the other thread.

And he states that his origin is top left from camera position, which would put it on the ‘back’ or top of the Y axis

FWIW, this is my first CNC build and I have found it quite easy to follow so far. I started the sub assemblies yesterday as other parts are finishing printing and it’s been pretty straight forward. Though, I’ve read the docs 2 or three times end to end before I tried assembling anything to get a feel for the flow.

I forked the docs and submitted a PR today to update some typos and grammer. I’ve been writing down some notes of things that can be updated that hopefully will help others moving forward as I am building this and will submit a PR for review to update the docs after I’m finished building.


Add 3dp housings for screen and board?

Another thought: Maybe adding endstops as an add-on option to the kit would be helpful? I completely forgot about them in my excitement to order.

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lol same, that and touchplate, which i still dont know how to use, but the endstops were easy enough to pick up on amazon next day for cheap.

Appreciate the info in this thread. Especially this…

Ordered LR3 kit, SKR, plus endstops and wiring that comes with dupont connectors. My crimper overly crushes through the 24AWG that arrived, making a weak easy to break connection. Have some 22AWG laying around, so will try crimping that instead.

If the crimps feel unreliable after giving them some test tugs, backup plan is to spoil my LR3’s endstops with soldered, heatshrink wrapped 22AWG, similar to what @vicious1 recommended earlier. Hopefully 22AWG will fit the prints, about to find out…

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I gave up trying to crimp them myself, as soon as i tried pulling the plugs out, they’d give up… ive crimped different connectors for years with no issue, but jst type just defeat me…

So now, i use 2S 3pin balance charge cables from amazon (or any radio control model shop), they’re the right connectors (jst-xh 2.5mm iirc) and pre-wired, so a quick solder to some longer cable and some heatshrink and no faffing with those flippin crimps!!

Heres an example JST XH2.5 3Pole Balance Connector Extension Wire for 2S 7.4V Lipo Battery 711331893499 | eBay

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Based on the pic, guessing builds with SKR boards should make ~2’ ( ~600mm) wiring lengths for Z Stop & Z Stop M, wired endstops? ( 2 * Pi * ZStopLength * 2.25 )

LR3 Kit came with Dupont connectors on the steppers and extension wires. Ok to use as-is?

LR3 build doc Wire Routing section says to read Control pages, the Control → SKR page recommends Molex instead of JST, including removing JST shields so stepper/endstop wiring make better connections.

Unless someone recommends otherwise, am going ahead with just making the Dupont connectors work, with the JST shields removed. Duponts seem to fit tight enough. Will ensure taped/grommet/other strain relief where possible to avoid wiring shaking loose when in use.




How should wiring extension be connected, with strain relief, especially for the X Axis stepper/endstops that will be moving?

Currently… to ensure connectors are not strained/pull-apart, bend extension wiring back on itself couple of times, then tightly wrap insulation tape ~3 times either side of the dupont connectors.

Planning to additionally heatshrink over at least the dupont connections. If I have large enough heatshrink, will wrap the zig-zagged wiring even. Too much? Everything gets shoved into 3/4" mesh cable protector, velcro fastened to left ~40% of the beam.

For the Rail’s Y and Z steppers/endstops, which won’t be moved/flexed, I used soldered Butt Connectors, wrapped with heat shrink, then shoved wiring through 1/2" mesh cable protector.

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That will work or you should have enough length to move the connector up to where it will not move on the core? What you have looks pretty good though if you keep the bend radius relaxed.


Thanks Ryan, will stick with that for now then. Seemed like quick reliable enough way to connect, will look neater when shoved into cable protector. Curious what beautiful/elegant reliable cable management solutions others have come up with.

There is enough extension to get connectors to be stationary and zip tied to the Core. But then I’d have to either shorten and crimp/solder the excess stepper/endstop wiring, or, make an unsightly bundle. Might revisit later, today’s goal is wire and power up my LR3.


Better layout? Looked at connecting wire extension on the core, placing connectors between the two top zip ties. Looping excess stepper/endstop wire within 3/4" cable protector.

Pics below do not show the insulation tape, heatshrink and cable protector that will be added to secure and pretty it up.

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  • Can 24V power supply be used with SKR Pro 1.2 as-is?
  • Is chopping firmware update required, or just recommended?
  • Is this a recommended enhancement to increase torque and reduce missed steps?
  • Can the Kit’s steppers and drivers handle, any lifetime, excessive heat concerns, and/or other issues to be aware of?

My V1E LR3 Kit came with a Kastar 12V 6A power supply, which works great. But…

I happen to have a Mean Well HLG-240H-24A 24V 10A lying around. So…


  • SKR Pro 1.2 User Manual says “… Motherboard parameters … Input voltage: DC12V- DC24V …”.
  • Misc forum post suggest switching power supply to 24V will work without firmware updates. For example 12v-vs-24v-powersupply-for-skr-pro-1-2 discussion.

Sounds like, switching power supply to 24V will work. But, if I additionally push firmware update, with chopping modified, that’ll enable rapid non-cutting movements to be configured faster.

But kit’s NEMA17 steppers spec says 4.2V, so I’m wondering whether changing to 24V has some cons I/we should be aware of.


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The voltage should make zero difference at the speeds we run. If you want to swap it everything will work as is.


Regret soldering the Y-axis endstops already. I should’ve used decent tight spade connectors, rather than making beautifully soldered heatshrink connections to the proud/exposed, but somewhat fragile Y-axis endstops.

My LR3 fell off my janky 5’x10’ sled during first vertical lift for storage. Naturally, the Y-axis endstop decided to cushion the fall with the switch metal spring arm disappearing off somewhere into the garage ether, never to be found again. Fortunately, I had an extra endstop available and was able to scavenge the arm.


  • Store and access LR3 when sober and alert.
  • Order a few extra spare endstops.
  • Use spade connectors for Y-Axis endstop, instead of soldering, until if/when design is tweaked with a shroud or outer bumper to provide some protection for the Y-Axis endstop.
  • Don’t route wiring too tight for soldered connections, leave additional extra/flex for future repairs.
  • Consider looking for hardy robust endstops that can take some abuse. Any suggestions?