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trying to figure out steps per mm
« on: July 19, 2016, 03:39:46 PM »
Trying to figure out my steps per mm Using the Rep Rap Calculator

Here is the link to the NEMA 23 Steppers that i bought as a kit with the cnc controller.

http://www.ebay.ca/itm/3-Axis-3A-Stepper-Controller-Cnc-Kit-Nema23-24V-Psu-For-Milling-Machine-/401075212293?hash=item5d61f21005:g:Hq0AAOSwzJ5XZ8Oz

Here is the link to the leadscrew i have selected

http://www.banggood.com/T8-800mm-Stainless-Steel-Lead-Screw-Set-with-Shaft-coupling-and-Mounting-Support-p-1062920.html

From the above sites i was able to determine my:

Motor Step Angle 1.8
Leadscrew Pitch 2mm

I have the dip switches on my cnc board set to be at 1/8 micro step.

The part that i think im messing up is the pitch preset where i am only guessing that is m8 1.25 mm per rotation.

With the above information i get 800 steps per mm which seems absurd
PLEASE SOMEONE HELP ME if i roatate the rod 1 full revolution it travels 8.1mm

Am i just messing up the calculation???

Offline ger21

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Re: trying to figure out steps per mm
« Reply #1 on: July 19, 2016, 03:49:34 PM »
Looks like the screw is labeled vaguely, and the lead is actually 8mm.
So with 1600 steps per rev, divided by 8, you should have 200 steps/mm.
Gerry

2010 Screenset
http://www.thecncwoodworker.com/2010.html

JointCAM Dovetail and Box Joint software
http://www.g-forcecnc.com/jointcam.html
Re: trying to figure out steps per mm
« Reply #2 on: July 19, 2016, 03:53:56 PM »
Where did you get the 1600 im curious
Re: trying to figure out steps per mm
« Reply #3 on: July 19, 2016, 04:06:49 PM »
I have entered the setting at 200steps per mm , if i get my calipers and move the z axis down 10 mm on mach3 display should that be 10mm of travel on the leadscrew ?

Offline ger21

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Re: trying to figure out steps per mm
« Reply #4 on: July 19, 2016, 04:46:19 PM »
If the display (DRO) shows 10mm, then the Z axis should move 10mm.
Gerry

2010 Screenset
http://www.thecncwoodworker.com/2010.html

JointCAM Dovetail and Box Joint software
http://www.g-forcecnc.com/jointcam.html
Re: trying to figure out steps per mm
« Reply #5 on: July 19, 2016, 05:12:00 PM »
Thanks for your quick replies i think im on to something . I have a video here to show you what i actually get when i move the z axis down 10 mm on the DRO



https://www.youtube.com/watch?v=r5UPgpz9q7o

Thanks again for your help it looks though as if im only seeing close to 5 mm when i move it 10 on DRO any ideas?

Offline ger21

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Re: trying to figure out steps per mm
« Reply #6 on: July 19, 2016, 05:20:02 PM »
Then change it to 100 steps/mm
Gerry

2010 Screenset
http://www.thecncwoodworker.com/2010.html

JointCAM Dovetail and Box Joint software
http://www.g-forcecnc.com/jointcam.html
Re: trying to figure out steps per mm
« Reply #7 on: July 19, 2016, 05:49:08 PM »
it was actually the other way . it was 400 steps per mm. Thanks so much for your help!

Offline ger21

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Re: trying to figure out steps per mm
« Reply #8 on: July 19, 2016, 07:56:31 PM »
Where did you get the 1600 im curious

Steppers are 200 steps/rev.
With 1/8 microstepping, it's 8x 200.
Gerry

2010 Screenset
http://www.thecncwoodworker.com/2010.html

JointCAM Dovetail and Box Joint software
http://www.g-forcecnc.com/jointcam.html
Re: trying to figure out steps per mm
« Reply #9 on: April 15, 2017, 08:52:32 PM »
Im Back !!! i am trying to add a rotary axis,,, i cannot get the axis to move as the A , only the X and is there some sort of settings to change this to be a rotary axis in mach 3?  here is a video to help explain.

https://www.youtube.com/watch?v=o54M_phYJpY

Thanks!