Final parts verification for LR4

LowRider CNC Advice
1

I have a few parts left to select for my LR4 2’x4’ build.

Belts - I am currently planning to use Gates GT2 9mm belts. I can’t see where the 9mm vs 10mm would cause an issue, right?

Board - Is the Jackpot, SKR, or something else the most performant option? I would like to have the option to use a laser in the future. The software side doesn’t bother me; things like klipper, embedded linux, flashing firmware, etc are no problem. I saw those new boards from BTT that are purpose built for CNC, but they only have 4 drivers. I can’t tell if they support adding more drivers through expansion boards though.

Leadscrews - I have left overs from a MK3S to MK4 upgrade. They should work but I think they will stick out pretty high right? If so I think I will just buy the right size from the shop.

Plates - I will order from the shop.

Already selected/purchased: (No questions for these, but open to commentary. Please be gentle if I have made any grave errors.)

Motors - I ordered the LDO BLV kit from Printed Solid. It is on clearance and all the motors meet spec. I’m planning to use the 0.9 degree steppers for Z and the single 40mm motor for X. (It still has sufficient holding torque.) This was under $50 for five LDO motors, so I guess fingers crossed it works.

PLA - After reading the PLA testing results in this forum, I sent a message to Printed Solid and they said their Jessie PLA in the Natural color would be the stiffest as it has minimal additives. This is no surprise but it looks like I won’t have a fun color for my parts unless I paint them. (Note - This is not the Elixer PLA. That also comes in the natural color but that has additives to increase toughness, which is of course different than stiffness.)

Printing - The recent developments in “brick layers” for perimeters are very interesting. I sliced the core and the XY min/max parts and the GCODE preview looks good. I printed a gantry clip with brick layers and it came out without issue. I will print a “Califlower Calibration STL” with bricklayers and the same settings to verify dimensional accuracy before I start the main jobs.

The testing I’ve seen indicate improvements in stiffness and layer adhesion. I am not set up to A/B testing on the LR4 parts, but I think brick layers is worth investigating by this community.

Tubes - I took test clips with me and picked up some 1 1/4" 16ga (0.065) polished and buffed stainless. It was a little more expensive, but… shiny!

Linear rails - I ordered HIWIN rails from BST Automation on AliExpress. I think they are a legitimate seller, fingers crossed again I suppose.

Tool - Carbide ER-11 compact router. I couldn’t pass this up for $60. 65mm diameter mount.

Thanks for reading all that. I’m looking forward to be build but it will be a few weeks until all the parts arrive and I have everything printed.

2

I’m rather biased towards the Jackpot but I do believe it is the best option. Wanting to use a laser in the future shifts it further in favor of the Jackpot.

See this section in the docs that describes the differences:
https://docs.v1e.com/electronics/jackpot/#jackpot-vs-the-skr-pro

3

I’m pretty biased toward the Jackpot as well. If you’re comfortable with Marlin, then you should look at the other options, but if you’re relatively new to CNC, then I think the Jackpot is great, and a smokin’ deal. I started with an SKR Pro until the Jackpot was available. I haven’t ever considered going back.

I’m not sure what performance you’re concerned with, so that could just be my ignorance. I have (on rare occasion) seen my machine pause on a large trochoidal milling file, but it resumes spontaneously and I haven’t seen any changes in the cut. Otherwise, my Jackpot keeps up with both my CNC gcode, and my Laser code from Lightburn.

1 Like
4

Regarding performance, I don’t know either. I’m thinking if I want to do higher resolution engravings the files would get pretty large. But I plan to have a raspberry pi in the mix and stream the gcode from CNC.js so maybe the board doesn’t need to do as much.

5

It is my understanding that from a performance and efficiency standpoint, at least on a Jackpot, you would be better off running gcode files straight from the SD card. Using a gcode sender isn’t offloading any work, it’s just streaming gcode line by line instead of letting FluidNC read the gcode file directly. It would be like if I was sitting next to my wife on the couch and texting her on my phone instead of talking directly. If my battery died, that conversation is over. In that case, we can just pick up where we left off talking, but in the CNC world, you’re starting the whole conversation over. Sure, it works, but it’s a little odd. (Maybe I took that analogy a little too far. :laughing:)

6

True. I was thinking of how klipper works.