- October 20, 2017 at 3:29 pm #46359
I just bought this “8mm T8x2 Threaded Rod for Trapezoidal ACME Lead Screw“. Is this the right one to replace my threaded rod on my MPCNC with? I know I probably should’ve asked first before buying it but either way, no biggie.
Running DIV268N drivers at 1/16 steps. Can anyone tell me what the steps per mm is that I would need to enter/change in Marlin?
ThanksOctober 20, 2017 at 3:40 pm #46360
You should be fine just use my firmware for the rambo mini and change the board to whatever board you have.October 20, 2017 at 3:47 pm #46363
Oh OK. I’m using your firmware now, but for ramps T8 threaded rod. So I’m guessing it would be easier to do it the way you said rather than changing the values needed to make it rightOctober 20, 2017 at 4:38 pm #46370
Just cut the Z value in half on the ramps version, either way only one edit (I’m 99% sure).October 20, 2017 at 4:55 pm #46373
I think on mine might have to be much less than half. My steps per mm on Z right now is 2600. It is a fine thread 8mm rod.
When you said to reduce it by half, did you mean from default 400? I think default was 400?? Could be wrongOctober 20, 2017 at 6:30 pm #46376
Hi John. If this math is correct, then your steps per mm should be 1600.
You are using a TR8*2, which has:
(motor step angle x driver microsteps) / (thread pitch x starts) = steps/mm
For a 1.8º motor: (200 x 16) / (2 x 1) = 1600 steps/mm
For a 0.9º motor: (400 x 16) / (2 x 1) = 3200 steps/mm
Please someone correct me if wrong.
Hope it helps, Martin.October 20, 2017 at 6:39 pm #46377
Forgot to mention, if you have EEPROM enabled you will need to update your steps/mm there too (or just there :P).October 20, 2017 at 6:42 pm #46378
Im not at a computer to check but that doesn’t sound right. You can verify by matching the minirambo z steps.
The t8’s should be 4 start.October 20, 2017 at 6:52 pm #46379
OK thanks guys,
I’ll have a look at the rambo config.h. I also think this is a 4 start threadOctober 20, 2017 at 7:18 pm #46381I just bought this “8mm T8x2 Threaded Rod for Trapezoidal ACME Lead Screw“. Is this the right one to replace my threaded rod on my MPCNC with? I know I probably should’ve asked first before buying it but either way, no biggie. Running DIV268N drivers at 1/16 steps. Can anyone tell me what the steps per mm is that I would need to enter/change in Marlin? Thanks
uhmmm, that’s a TR8*2, or you are using TR8*8 like stock MPCNC? (https://shop.vicious1.com/collections/parts/products/300mm-leadscrew-and-nut)
TR8*8 has 4 starts and a 2mm pitch, so 8mm lead. But for a TR8*2 is like I said earlier.
If you do have a TR8*8 then your steps/mm should be 400. (x16 microsteps, 1.8º motor)October 20, 2017 at 8:00 pm #46383
I can only go by what it is sold to me as, and indeed it is TR8X2
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