Jackpot3 stepper configuration

Linlor · March 12, 2026, 5:09pm

Given I am new on the Jackpot3 and FluidNC setup as I just swapped in from an old RAMPS/Marlin board, I have been reading as much as I can on the Fluidnc configs etc. and I have done some preliminary math with my steppers to see what settings I need to adjust in the config.yaml file. My RAMPS board using 8825 drivers had lower amperage/voltage so I ask for some feedback from folks on my settings below before I put on the board and try it out. Don’t want to fry anything.

Steppers are JK42HS48-1804.

Rated current: 1.8 A.
Safe running current: 1.25–1.4 A.

TMC2226 driver calcs put a suggested setup of:

run_amps 1.2A
homing_amps 1.0A
hold_amps .5A

I do not know the TMC2226 driver at all. Steep learning curve here. Do these settings seem reasonable for these stepper motors?

The second part is steps_mm. I am using GT2 10mm belt so 2 mm per tooth and 20 teeth.
Big question for me on this part is the microsteps default of 8. I read somewhere that 16 provides a stable medium ground for cnc routers? Using the 16 microsteps as a start I have a steps_per_mm setting of 80. So if I put everything together for the config.yaml stepper setup, I have:

x:

```
steps_per_mm: 80.000
```
```
max_rate_mm_per_min: 9000.000
```
```
acceleration_mm_per_sec2: 200.000
```
```
max_travel_mm: 1220
```
```
soft_limits: false
```

homing:

```
  cycle: 2
```
```
  positive_direction: false
```
```
  mpos_mm: 3
```
```
  feed_mm_per_min: 300.000
```
```
  seek_mm_per_min: 1500.000
```
```
  settle_ms: 500
```
```
  seek_scaler: 1.100
```
```
  feed_scaler: 1.100
```
#X

motor0:

```
  limit_neg_pin: gpio.25:high
```
```
  limit_pos_pin: NO_PIN
```
```
  limit_all_pin: NO_PIN
```
```
  hard_limits: false
```
```
  pulloff_mm: 4.000
```

  tmc_2209:

```
    uart_num: 1
```
```
    addr: 0
```
```
    cs_pin: NO_PIN
```
```
    r_sense_ohms: 0.110
```
```
    run_amps: 1.200
```
```
    homing_amps: 1.000
```
```
    hold_amps: 0.500
```
```
    microsteps: 16
```
```
    stallguard: 0
```
```
    stallguard_debug: false
```
```
    toff_disable: 0
```
```
    toff_stealthchop: 5
```
```
    toff_coolstep: 3
```
```
    run_mode: StealthChop
```
```
    homing_mode: StealthChop
```
```
    use_enable: false
```
```
    direction_pin: I2SO.1
```
```
    step_pin: I2SO.2
```
```
    disable_pin: I2SO.0
```

Most of the settings are the default build sent except for my stepper specific settings. I don’t have limit switches setup yet either.

If I put these settings for each stepper motor in the config.yaml, is there any areas that I am putting myself at risk? I can start digging into StrealthChop and acceleration et al. later as I want to see if I can get a simple setup to start with

vicious1 · March 12, 2026, 5:30pm

I bet you are going to be at 0.9a. Whatever your run amps are only go 0.1-0.2A less for both homing and holding. (Y will just be holding somtimes while X is driving, so they still need to be strong).

The best test is let them run for a while, make a giant circle gcode and just let it run in the air, in motion for at least 20 minutes. Get the stepper temps to 45C no more than 50C, that is the sweet spot. Then set them all the same.

it doesn’t matter. 8 gives you a higher maximum speed because of less overhead on the processor.

The biggest thing to what out for is extra empty spaces hidden at the end of lines and things. The config is blank space sensitive.

Linlor · March 12, 2026, 8:49pm

Thanks very much Ryan;

I have a file that runs circles for about 20 mins. Edited holding to 1.0 as well.

Seems I have a decent starting spot

Cheers

Don