Help with Prusa threaded rod calculator z-axis steps

Hello!

I've been setting up Marlin for a MK2 clone I'm working on. In configuration.h I need to set the steps for my z axis. I'm using a T8 acme rod. I believe it is T8 2 8. I can't seem to find that as an option on the pull down. It shows an M8 but that is a regular threaded rod. Not the same pitch as a T8?

Stainless Steel
Diameter: 8 mm
Thread pitch: 2 mm
Helical pitch: 8 mm
Length: 300mm


Anyone know the correct steps to put in Marlin?

Thanks

Max:-)

Edited 1 time(s). Last edit at 04/09/2017 05:04PM by Max3Dcal.

With lead screws it all depends on the number of starts you have. A start is a parallel thread that helps with stability but also means the feedrate needs to be increased. So to get the pitch for the feedrate calculate you need to multiply the thread pitch by the number of starts (2,3 or 4). most leadscrews for 3d printing I've seen have been 2 or 4 but if you are unsure go back to the place you got it (or read the online description) and it will tell you.

As for the online calculate there is a box to the left of the drop down that lets you enter your own pitch

OKay then, I listed it above thread pitch 2mm, so that is all I need to know? I thought starts related to how much torque.

You will need to know the starts as well and multiply the pitch to get the lead

[en.wikipedia.org]

And yes starts are loosely related to torque

You can tell how many starts the rod has by looking at the rod end and counting how many thread ends there are.
If it has 4 ends (most common theses days) then your steps/mm=400 @1/16 microstepping

Edited 1 time(s). Last edit at 04/10/2017 04:18AM by obewan.