584,865 active members*
5,013 visitors online*
Register for free
Login
IndustryArena Forum > WoodWorking Machines > DIY CNC Router Table Machines > FineLine Automation > Saturn router Overall turns ratio “Turns per inch”
Page 1 of 2 12
Results 1 to 20 of 36
  1. #1
    Join Date
    Aug 2018
    Posts
    621

    Saturn router Overall turns ratio “Turns per inch”

    I’m in the process of setting up the parameters on my controller and I wanted to know if someone with a Saturn with Nema34 steppers could chime in.

    Does anyone know what the turns per inch is on this machine? My understanding of turns per inch is it’s a mechanical setting based on the rack and Pinion drive of the machine. So I would assume that the brand of Nema34 steppers shouldn’t matter and it has to do with the mechanical gear ratio of the machine. I know there’s a mathematical formula but with out having all the specs of the rack and pinion I wouldn’t know how to figure it out.

    I also know that you can figure it out with a ruler but you really need a dial indicator which I don’t have. I’m wondering if someone can save me some time by telling me what the setting is for this machine?

    Thanks and maybe Nate can chime in on this one?

  2. #2
    Join Date
    Apr 2010
    Posts
    109

    Re: Saturn router Overall turns ratio “Turns per inch”

    On Nates website it says the NEMA 34 pinion spindles are 3.2:1 when used with the 20 tooth motor pulley. I believe the pinions themselves are 1". 3.2/3=1.067 inches per revolution. https://www.finelineautomation.com/p...le?taxon_id=38
    Not sure if that is exactly what you were looking for.
    Erik

  3. #3
    Join Date
    Oct 2016
    Posts
    236

    Re: Saturn router Overall turns ratio “Turns per inch”

    Quote Originally Posted by Erik F View Post
    On Nates website it says the NEMA 34 pinion spindles are 3.2:1 when used with the 20 tooth motor pulley. I believe the pinions themselves are 1". 3.2/3=1.067 inches per revolution. https://www.finelineautomation.com/p...le?taxon_id=38
    Not sure if that is exactly what you were looking for.
    Erik
    This is very close, except that you should be dividing 3.2 by Pi (3.14159...). So 3.2/3.14159 = 1.0186. That said, you are going to have to adjust this number a little because the gear pitch diameter is not EXACTLY 1.000", the belt ratio is not exactly 3.2 and the anti-backlash system on the Saturn machine pushes the gear further into the rack than it is designed for, so the effective gear diameter is a little less than 1. This will get you close, then you can fine tune it by moving the machine some distance and measuring.

    -Robert

  4. #4
    Join Date
    Nov 2014
    Posts
    729

    Re: Saturn router Overall turns ratio “Turns per inch”

    That's correct, Robert. And this is where the large rectangles come into play so you can measure the diagonals to not only make sure they are equal but also that they match what they're supposed to measure. Equal measurements are good but if the diagonal is supposed to be 52", for instance, and it measures 52.25" then you're still not there. All the calculations in the world don't matter if the gantry isn't square and the diagonals don't measure out correctly. DAMHIK...

    David
    David
    Romans 3:23
    Etsy shop opened 12/1/17 - CurlyWoodShop

  5. #5
    Join Date
    Aug 2018
    Posts
    621
    Quote Originally Posted by DDgitfiddle View Post
    This is very close, except that you should be dividing 3.2 by Pi (3.14159...). So 3.2/3.14159 = 1.0186. That said, you are going to have to adjust this number a little because the gear pitch diameter is not EXACTLY 1.000", the belt ratio is not exactly 3.2 and the anti-backlash system on the Saturn machine pushes the gear further into the rack than it is designed for, so the effective gear diameter is a little less than 1. This will get you close, then you can fine tune it by moving the machine some distance and measuring.

    -Robert
    So since this is all new to me I just wanted to be clear.

    What you guys are saying is one turn of the stepper equals close to 1” of axis travel?

    If so, what about the z axis, since it’s a ball screw?

    Thanks again

  6. #6
    Join Date
    Mar 2003
    Posts
    35538

    Re: Saturn router Overall turns ratio “Turns per inch”

    You also have to factor in the microstep setting on your drives.
    At 1/8, you have 1600 steps per rev of the stepper. At 1/10, it's 2000.
    Gerry

    UCCNC 2017 Screenset
    http://www.thecncwoodworker.com/2017.html

    Mach3 2010 Screenset
    http://www.thecncwoodworker.com/2010.html

    JointCAM - CNC Dovetails & Box Joints
    http://www.g-forcecnc.com/jointcam.html

    (Note: The opinions expressed in this post are my own and are not necessarily those of CNCzone and its management)

  7. #7
    Join Date
    Aug 2018
    Posts
    621
    Quote Originally Posted by ger21 View Post
    You also have to factor in the microstep setting on your drives.
    At 1/8, you have 1600 steps per rev of the stepper. At 1/10, it's 2000.
    I’m not talking about steps per revolution, I’m talking about overall turns ratio “how many stepper shaft turns per inch of axis movement “. Two different things with my controller.

    If you’re saying that the steps per revolution affect the turn ratio please explain and give a different formula.

    Right now I’m looking for the turns ratio for the ballscrew z axis.

    Thanks

  8. #8
    Join Date
    Oct 2016
    Posts
    236

    Re: Saturn router Overall turns ratio “Turns per inch”

    Quote Originally Posted by Ntl View Post
    So since this is all new to me I just wanted to be clear.

    What you guys are saying is one turn of the stepper equals close to 1” of axis travel?

    If so, what about the z axis, since it’s a ball screw?

    Thanks again
    That is correct. 1 full rotation of the motor shaft is close to 1 inch of travel for the X and Y axis. Gerry's comment is also correct...you have to account for how many steps per motor revolution you use on your steppers. That will be important because your control software (Mach 3, Mach 4, UCCNC, etc...) will want steps/pulses per inch or something similar so that it can translate the G-code into motor turns.

    The Z-axis is MUCH easier to figure out. The ball screw has a 5mm pitch and it is directly connected to the motor shaft (i.e. it moves 5mm for 1 turn of the motor). 1mm = 0.03937 inches, so you get 0.19685" per motor revolution on the Z-axis. A nice result of that is that your Z-axis motor needs a little less precision than the others.

    -Robert

  9. #9
    Join Date
    Apr 2010
    Posts
    109

    Re: Saturn router Overall turns ratio “Turns per inch”

    Sorry! forgot the other half of my pi ! The software I was running only wanted to know distance per revolution and there was another data box for how many steps per rotation...its the same but different.

  10. #10
    Join Date
    Aug 2018
    Posts
    621
    Quote Originally Posted by DDgitfiddle View Post
    That is correct. 1 full rotation of the motor shaft is close to 1 inch of travel for the X and Y axis. Gerry's comment is also correct...you have to account for how many steps per motor revolution you use on your steppers. That will be important because your control software (Mach 3, Mach 4, UCCNC, etc...) will want steps/pulses per inch or something similar so that it can translate the G-code into motor turns.

    The Z-axis is MUCH easier to figure out. The ball screw has a 5mm pitch and it is directly connected to the motor shaft (i.e. it moves 5mm for 1 turn of the motor). 1mm = 0.03937 inches, so you get 0.19685" per motor revolution on the Z-axis. A nice result of that is that your Z-axis motor needs a little less precision than the others.

    -Robert
    I’m using Centoid Acorn with cnc12 and the two (steps per revolution and turns per inch) are separate settings in the setup wizard. I already have my Microstepping set up on my g214 drivers and in my configuration wizard.

    I also just tested 1 turn = one inch setting in the turns ratio on the configuration wizard and moved a axis one inch in the cnc12 software and I got one turn of the stepper motor shaft so it appears I’m good to go for x and y axis for a starting point.

    Ok so I also just tested the Z axis Set to 5.08 turns per inch based off the 5mm pitch info you provided and a little over 5 turns gives me 1” of z axis movement.

    Keep in mind my motors aren’t installed on the machine yet and I’m just bench testing everything right now.

    Thanks guys for letting me know the specs on the table, Nate is a tough guy to get ahold of.

  11. #11
    Join Date
    Sep 2005
    Posts
    1740

    Re: Saturn router Overall turns ratio “Turns per inch”

    I can give you the Steps on my machine and if you have a standard 1.8 deg NEMA motor and the same Pro gear drives I have mounted, and the same Rack it should be the same. Steps are equaling the distance traveled. Its
    an Inch machine.

    X & Y = 2038 Steps Vel 600 Acc 50 Z = 10160 Steps Vel 150 Acc 30 this is off a working machine.
    Retired Master Electrician, HVAC/R Commercial. FLA Saturn 2 4x4 CNC Router Mach4 Kimber 1911 45ACP

  12. #12
    Join Date
    Aug 2018
    Posts
    621
    Quote Originally Posted by wmgeorge View Post
    I can give you the Steps on my machine and if you have a standard 1.8 deg NEMA motor and the same Pro gear drives I have mounted, and the same Rack it should be the same. Steps are equaling the distance traveled. Its
    an Inch machine.

    X & Y = 2038 Steps Vel 600 Acc 50 Z = 10160 Steps Vel 150 Acc 30 this is off a working machine.
    I have Gecko 214 drivers and mine are set at 125 micro steps = 25000 per Geckos advice based off the information I provided to them. The Acorn controller and my steppers handle the setting fine, and the gecko 214 goes up to 256 micro steps.

    Right now the default maximum Velocity setting is 50in a minute max rate and accel/decel default setting is .5 seconds.

    I think the confusion people are having is that I’m using a Centroid Acorn controller and they probably have no experience with the controller. The setup and settings are going to be different than the other controllers.

    I also am new to cnc and this is the first and only controller I’ve used.

    Here is a picture of the control configuration wizard, maybe you can get a better idea of what I’m working with.

    Thanks
    Attached Thumbnails Attached Thumbnails 793E8D0B-6B13-4D6D-AAA0-EDBB5E063E87.jpg  

  13. #13
    Join Date
    Mar 2003
    Posts
    35538

    Re: Saturn router Overall turns ratio “Turns per inch”

    I’m not talking about steps per revolution, I’m talking about overall turns ratio “how many stepper shaft turns per inch of axis movement “. Two different things with my controller.

    If you’re saying that the steps per revolution affect the turn ratio please explain and give a different formula.
    No, I just didn't realize they were separate settings in the Acorn.
    Gerry

    UCCNC 2017 Screenset
    http://www.thecncwoodworker.com/2017.html

    Mach3 2010 Screenset
    http://www.thecncwoodworker.com/2010.html

    JointCAM - CNC Dovetails & Box Joints
    http://www.g-forcecnc.com/jointcam.html

    (Note: The opinions expressed in this post are my own and are not necessarily those of CNCzone and its management)

  14. #14
    Join Date
    Mar 2008
    Posts
    1762

    Re: Saturn router Overall turns ratio “Turns per inch”

    Ntl…
    You are correct in requesting the turns per inch spec as it is needed. That said, unless you want to guess you will need to provide the motor pulley # or teeth, the large pulley # of teeth and the # of teeth on the pinion gear. Then I will give you an accurate turns per inch.

    I would also suggest that you set your drives to 1600 or 3200 steps per rev as there is no need on a router, where torque is a benefit and noise seldom matters, to run at crazy high microstepping numbers. 1600 would be my preference as it offers step resolution in the 1/2 thousandth range. 3200 if you do printed circuit work and can get the backlash out of the R & P. 1/10th microstepping is, in my opinion the single worst number that can be selected. More machines that lose steps are running 1/10 (2000/rev) than any other setting.

    Here are the numbers that I show for your machine: 1.0186 motor revs per inch if what is said above is accurate.
    Gary Campbell CNC Technology & Training
    GCnC411 (at) gmail.com www.youtube.com/user/Islaww1/videos

  15. #15
    Join Date
    Sep 2005
    Posts
    1740

    Re: Saturn router Overall turns ratio “Turns per inch”

    Quote Originally Posted by Ntl View Post
    I have Gecko 214 drivers and mine are set at 125 micro steps = 25000 per Geckos advice based off the information I provided to them. The Acorn controller and my steppers handle the setting fine, and the gecko 214 goes up to 256 micro steps.

    Right now the default maximum Velocity setting is 50in a minute max rate and accel/decel default setting is .5 seconds.

    I think the confusion people are having is that I’m using a Centroid Acorn controller and they probably have no experience with the controller. The setup and settings are going to be different than the other controllers.

    I also am new to cnc and this is the first and only controller I’ve used.

    Here is a picture of the control configuration wizard, maybe you can get a better idea of what I’m working with.

    Thanks
    Gary who is in NW Michigan makes a career out of retro fitting and designing control systems is on here from time to time and he is an expert at the Acorn. He is over on their forum. There has been some discussion and I am not smart enough at CNC to comment, but the more micro steps your using the less power you have in running and holding. Others can fill in the detail. But the standard NEMA motor @ 1.8 deg , takes 200 standard full steps to complete one 360 deg rotation of the output shaft. And it kind of makes sense that if that same motor is now being driven at 24,000 steps to complete that one rotation something may be compromised in the power output.

    Ahh he posted before I did and said in more intelligent language what I was trying to say.
    Retired Master Electrician, HVAC/R Commercial. FLA Saturn 2 4x4 CNC Router Mach4 Kimber 1911 45ACP

  16. #16
    Join Date
    Aug 2018
    Posts
    621
    Quote Originally Posted by islaww View Post
    Ntl…
    You are correct in requesting the turns per inch spec as it is needed. That said, unless you want to guess you will need to provide the motor pulley # or teeth, the large pulley # of teeth and the # of teeth on the pinion gear. Then I will give you an accurate turns per inch.

    I would also suggest that you set your drives to 1600 or 3200 steps per rev as there is no need on a router, where torque is a benefit and noise seldom matters, to run at crazy high microstepping numbers. 1600 would be my preference as it offers step resolution in the 1/2 thousandth range. 3200 if you do printed circuit work and can get the backlash out of the R & P. 1/10th microstepping is, in my opinion the single worst number that can be selected. More machines that lose steps are running 1/10 (2000/rev) than any other setting.

    Here are the numbers that I show for your machine: 1.0186 motor revs per inch if what is said above is accurate.
    Motor pulley =20 teeth
    Rack pulley =64 teeth
    Pinion gear =20 teeth

    As far as the microstep setting goes:
    The setting was suggested by the drive manufacturer I didn’t just randomly pick the Microstep setting he said my controller can handle it and the drivers have no problem handling it. So for now I’m running it and if there’s a problem it’s easy to change.

    Thanks for the help guys
    Dan

  17. #17
    Join Date
    Mar 2008
    Posts
    1762

    Re: Saturn router Overall turns ratio “Turns per inch”

    Dan...
    The 1.0186 motor revs per inch number I gave you should be accurate. The steps per rev is a user selection. Your choice. Remember that torque and microsteps are inversely proportional. Higher the microstepping level, lower the torque. and visa versa.

    You don have to believe me: https://www.machinedesign.com/archiv...stepping-myths

    I have put the cliffs notes below. Remember this is holding torque and may actually be 30-50% less when moving, depending on rpm.
    Gary Campbell CNC Technology & Training
    GCnC411 (at) gmail.com www.youtube.com/user/Islaww1/videos

  18. #18
    Join Date
    Aug 2018
    Posts
    621
    Quote Originally Posted by islaww View Post
    Dan...
    The 1.0186 motor revs per inch number I gave you should be accurate. The steps per rev is a user selection. Your choice. Remember that torque and microsteps are inversely proportional. Higher the microstepping level, lower the torque. and visa versa.

    You don have to believe me: https://www.machinedesign.com/archiv...stepping-myths

    I have put the cliffs notes below. Remember this is holding torque and may actually be 30-50% less when moving, depending on rpm.
    I thought holding torque didn’t matter on a cnc router and continuous torque is what matters? I guess I will just have to see if I have problems with a lack of torque once the machine is functioning. No offense but I talked to the driver manufacturer for a very long time and he told me that the high microsteps wouldn’t hurt anything it’s just there if I need it. I’ll let you know what happens and I will have more videos on my YouTube once the machine is finished.

    Thanks again for the calculations!!

    Dan

  19. #19
    Join Date
    Aug 2018
    Posts
    621
    Quote Originally Posted by islaww View Post
    Dan...
    The 1.0186 motor revs per inch number I gave you should be accurate. The steps per rev is a user selection. Your choice. Remember that torque and microsteps are inversely proportional. Higher the microstepping level, lower the torque. and visa versa.

    You don have to believe me: https://www.machinedesign.com/archiv...stepping-myths

    I have put the cliffs notes below. Remember this is holding torque and may actually be 30-50% less when moving, depending on rpm.
    Here’s a article that isn’t 15 years old.
    Attached Files Attached Files

  20. #20
    Join Date
    Sep 2005
    Posts
    1740

    Re: Saturn router Overall turns ratio “Turns per inch”

    NtI your Link does not work correctly.

    Gary is correct, your Gecko guy is selling micro steps. The holding torque is just a convenient way of measuring power available at the shaft. Where in wood routing are you going to need 20,000 step resolution? You need 100% dependable operation, no skips or missing steps. Gary makes a business out of CNC we or at least me anyway are hobby. I have done and retro fitted a couple of machines over the last 10 years, thats it.
    Retired Master Electrician, HVAC/R Commercial. FLA Saturn 2 4x4 CNC Router Mach4 Kimber 1911 45ACP

Page 1 of 2 12

Similar Threads

  1. Turns per inch IS8000 gravograph engraver
    By wcarrothers1 in forum Engraving Machines
    Replies: 0
    Last Post: 01-13-2017, 04:24 AM
  2. Changed over from 13 TPI to 2 Turns Per Inch, Help!
    By KnotsAboutWood in forum Mechanical Calculations/Engineering Design
    Replies: 1
    Last Post: 07-22-2010, 12:29 PM
  3. 1/2"-8 ACME 2 Start (4 turns per inch)
    By andy_ck87028 in forum Australia, New Zealand Club House
    Replies: 3
    Last Post: 04-04-2005, 03:44 AM
  4. Turns per inch to metric conversion
    By sixpence in forum DIY CNC Router Table Machines
    Replies: 1
    Last Post: 08-28-2004, 08:19 AM
  5. turns per inch vs threads per inch
    By pminmo in forum DIY CNC Router Table Machines
    Replies: 12
    Last Post: 08-18-2004, 03:27 PM

Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •