Need assistance calculating steps/mm for Z axis

OBELIKS

If I remember correctly you need 400 steps/mm
The lead screw has 2mm pitch and 4 leads. That means 8mm per rotation that is written in the description. Put that in to the calculator that @deckingman linked. You will get 400 steps/mm from there.

cyoung

This is how I have my steps/mm set up in the config file.

M350 X256 Y256 Z256 E256 I1 ; Configure microstepping without interpolation
M92 X1280 Y1280 Z6366 E6582 ; Set steps per mm

OBELIKS

This is better

M92 X1280 Y1280 Z6400 E6582 ; Set steps per mm
M350 X256 Y256 Z256 E256 I0 ; Configure microstepping without interpolation

deckingman

@cyoung said in Need assistance calculating steps/mm for Z axis:

@deckingman said in Need assistance calculating steps/mm for Z axis:

what we need to know is the lead (not pitch) of the screws

Printer started as a Folgertech FT-5. The website describes the lead screw this way: "T8 4 Start Lead Screw 8mm pitch "

Very bad description and I'll bet a pound to a pinch of Chinese excrement that it isn't 8mm pitch. I'd wager that it's 2mm pitch and 8mm lead which is what I wanted to know.

I see that everyone else has jumped in so I'll say no more, but you can re-read my post and do the maths base on 8mm lead if you want to.

deckingman

@obeliks said in Need assistance calculating steps/mm for Z axis:

This is better

M92 X1280 Y1280 Z6400 E6582 ; Set steps per mm
M350 X256 Y256 Z256 E256 I0 ; Configure microstepping without interpolation

Erm, no it's not better. In fact it's very bad indeed.

If you set steps per mm (M92) before the micro stepping (M350), then the steps per mm will be set for 16x micro stepping. Then when you put the M350 command in after, it will recalculate the steps per mm. So, if you use M92 before M350, the Z value needs to be 400 which get get converted to 6400 when the M350 is run. If you use 6400 to start with, it will get converted to 102,400 when micro-stepping is set to 256X.
https://duet3d.dozuki.com/Wiki/GCode#Section_M350_Set_microstepping_mode

OBELIKS

Ah, I missed this detail. Sorry.
But the steps/mm values should be correct.

deckingman

@obeliks said in Need assistance calculating steps/mm for Z axis:

Ah, I missed this detail. Sorry.
But the steps/mm values should be correct.

No worries. Yes it's 400 steps per mm @ 16X or 6400 @ 256X. I wasn't go to tell the OP that as he asked for help in calculating it, not for someone to tell him what they should be

As the saying goes, "Catch a man a fish and he'll feed himself for a day but show a man how to catch a fish and he'll feed himself for life".

cyoung

@deckingman said in Need assistance calculating steps/mm for Z axis:

As the saying goes, "Catch a man a fish and he'll feed himself for a day but show a man how to catch a fish and he'll feed himself for life".

I believe what you meant to say is "Give a man a fish and feed him for a day. Dont teach a man to fish...and feed yourself. He's a grown man and fishing's not that hard."

Thanks for the help.

deckingman

@cyoung There are multiple variations of that quote, attributable to multiple people. I prefer the version I used which basically means that it's better to teach someone how to do something, than to do it for then. Hopefully, if you need to calculate the steps per mm for anything in the future, you'll be able to do so without asking for someone to do it for you. Just trying to help, no offence meant or intended.

cyoung

@deckingman I was just being silly.

deckingman

@cyoung said in Need assistance calculating steps/mm for Z axis:

@deckingman I was just being silly.

Ahh OK. Add a next time, then I'll know. Always difficult to tell when you only see the words but not the facial expression.