Topic: Help with T8 Lead Screw Issues, Please.
Hello, I'm hoping someone can help me solve this issue I'm having, So I'll get to it.
I have the GEEETech Prusa i3 PRO-B Printer and when finished building it, I noticed one of the Threaded rods was buckled quite a bit. So I did some research and noticed the majority of people were actually swapping out their rods for lead screws.
So, I purchased these T8 L350mm Diameter 8mm Lead 4 Start lead Screws and the Specifications are as follows.
Specifications:
Lead Screw Diameter: 8MM
Lead: 8mm
Screw Length: 350mm
Screw Pitch: 2mm
My stepper motors are a Hybrid stepper motor 42SHD0034-20B http://www.geeetech.com/hybrid-stepper- … -1011.html
My problem is, I'm coming up with differing figures when working out the steps per millimetre with leadscrew driven systems.
I download a version of the Marlin firmware from this post over on the GEEETech forum which as apparently already been edited for the use of a BLTouch for the Prusa i3 Pro B and the T8 Lead Screw from this post here >http://geeetech.com/forum/viewtopic.php … mp;t=60826 and in his firmware, the steps are 400.96, see code below.
//#define DEFAULT_AXIS_STEPS_PER_UNIT { 81.5, 81.5, 2577.46, 94 }
#define DEFAULT_AXIS_STEPS_PER_UNIT { 81.5, 81.5, 400.69, 94 }
/**
Bear with me, Please?
Now, with this other guys Firmware, using the T8 Lead Screws here https://www.geeetech.com/forum/viewtopi … 647#p30268 the guy is using 2560 steps per mm and not 400.
Moving on, So I tried using this calculator here https://www.prusaprinters.org/calculator/ and this is where I become even more confused,... This is what I enter into the settings.
Motor step angle: 1.8° (200 per revolution)
Driver microstepping: 1/16 - uStep (mostly Pololu)
Leadscrew pitch: 2
Gear ratio: 1:1
The last one is the "Pitch presets" a few people have said use the: 1/4"-16 Acme (1.5875mm per rotation) and others have told me to use M8 - metric (1.25mm per rotation) and others have told me to just leave it, there's no T8 Lead Screw setting, as it's not been added.
I have noticed that none of the options in the "Pitch Presets" says 8mm per rotation, which is what my lead Screws move with one rotation.
Anyway, after I add the settings I get a figure of only 1600.00... now if my Lead Screws are a 4 Lead Start, do I then divide that 1600.00 by 4? which would give me 400?
Why are so many people giving me different figures for the same lead screws? It's gotten to the point now, where I'm virtually scared of entering any figure, lol... I don't want to get it wrong and break something, you see.
I do realise I have got a lot to learn and sadly, Maths was never my strong suit, could someone please, help me understand whats going on in Layman's Terms, please?
I thought I could just use the firmware that has already been edited for the BLTouch and the T8 Lead Screws, as I've already got the BLTouch also and if that firmware is already correct, I could just use that and then take my time learning everything else later, once I have this printer up and running.
I appreciate your Patience on this one, Please.
Thank you, so much.