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Community Favorite Alternative to the Lead Screw Upgrade Kit

Discussion in 'Mods and Upgrades' started by WheresWaldo, Nov 23, 2015.

  1. JOAQUIN PICCI

    JOAQUIN PICCI Member

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  2. JOAQUIN PICCI

    JOAQUIN PICCI Member

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    If original lead screw upgrade robo sells is TR8*4 so i should think the PITCH is 2mm? THe ones i bought says "PITCH=1MM"... so i they are TR8*8 like the ones at the begginin of the thread?
     
  3. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    This is how it works. Say you have:
    Tr 8*4 (P2)
    This reads:
    • Tr -- metric trapezoidal screw (30°);
    • 8 -- diameter: the screw is 8 mm thick across the peaks of the threads;
    • 4 -- lead: one turn advances the nut 4 mm;
    • P2 -- is the pitch (2mm)
    Pitch is the spacing (along the axis of the screw) of consecutive threads
    If not specified the PITCH and LEAD numbers are the same (normally)

    This is why they may not always be the same:

    Lead_and_pitch_in_screws.png
     
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  4. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    Now you have made my head hurt :)
     
  5. JOAQUIN PICCI

    JOAQUIN PICCI Member

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    Great. So if the pitch is mm, then it is a TR8*8 ? So its the same waldo is using in this thread
     
  6. JOAQUIN PICCI

    JOAQUIN PICCI Member

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    1 mm sorry
     
  7. JOAQUIN PICCI

    JOAQUIN PICCI Member

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    I dont understand if i have a TR8*8 or a TR8*1

    The pitch is 1MM
     
  8. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    Well, you will need to sanity check where you ordered them.
    If not specified lead = pitch. If they specified it at 1mm then lead does not equal pitch (maybe this is not a single-start thread).
    You should know what you bought :) If I translated the page correctly then I agree, those look like 1mm pitch:

    Type: trapezoidal screw
    diameter: 8mm
    Pitch: 1 mm
    Length: 300 mm


    Try those numbers and see if they work.
     
  9. JOAQUIN PICCI

    JOAQUIN PICCI Member

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    Great. I think im getting it

    So if the pitch is 1mm and it can be only single, double or tiple start.. the max. Lead is 3 ?
     
  10. WheresWaldo

    WheresWaldo Volunteer ( ͠° ͟ʖ ͡°)
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    @JOAQUIN PICCI I believe those are TR8*8, it is the most common lead screw available from Chinese factories. It is only a matter of changing one parameter in the firmware. You can even test it by sending M92 commands until you have the correct answer. M92 can be used in real time, for example:

    M92 Z400
    Sets number of Z steps to 400 for 1 mm of rise, typical of third party lead screws

    M92 Z800
    Sets number of Z steps to 800 for 1 mm of rise, value used in the Robo upgrade

    M92 Z2560
    Value used for 8 mm threaded rods

    M92 will set it temporarily, it does not survive a reboot unless stored in EEPROM. You can set it then move the extruder up 10 mm and measure. If it's wrong change the value and move it again. Once you have the correct value, edit Configuration.h and recompile and upload the firmware. I would be surprised if it is something other than 400.
     
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  11. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    This is exactly the approach we used on the DLP printer Z axis. I also used some cheap China leadscrews for that and had to largely guess on some of the values.
     
  12. JOAQUIN PICCI

    JOAQUIN PICCI Member

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    i have different end switches.. i think the adapter wont work. I have a ROBO R1
     
  13. JOAQUIN PICCI

    JOAQUIN PICCI Member

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    It costs me a lot to get the adapter inside the IDLER
     
  14. Matthew Bartlett

    Matthew Bartlett New Member

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    SO, with this mod, can you still reinstall the top cover?
     
  15. danzca6

    danzca6 Well-Known Member

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    Yes should be fine fitting the top back on.
     
  16. Krish

    Krish Member

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    Just wanted to mention, I've referred to this thread in a video I recently made. Its more to do with changing leadscrew motors instead of the method mentioned here using solid couplers.

    Its not a full guide, but it may be useful to some that are looking to do either the solid coupler or leadscrew upgrades using self sourced parts. It just gives a bit of an overview of the process I went through, as well as some issues I came across (mainly to do with things not lining up). I also customised the endstop switch brackets after making this video as I found the ones in this thread rotated too much and originally was slightly too big which could have also been a calibration issue on my printers part, but I've added a link to it below anyway.

    http://www.thingiverse.com/thing:1775587

     
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  17. WheresWaldo

    WheresWaldo Volunteer ( ͠° ͟ʖ ͡°)
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    I uploaded a newly modified version based on some of the things mentioned by @Krish. There is now a bit more taper to the hexagonal section as well as moving the micro-switch holes up an addition 0.1 mm. I did not incorporate the arms on both sides as the taper should account for any rotational issues.

    I uploaded the new version in as many file formats as Fusion 360 allows exporting so the source is there if you want to make changes such as those done by @Krish and others.
     
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  18. danzca6

    danzca6 Well-Known Member

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    Just wanted to bookmark this video here that shows how to replace the leadscrew in an integrated Nema 17 setup. I am pondering taking a standard Nema 17 apart and seeing if we can add the leadscrew to it. Would be cool! Anyway, this video should help if your leadscrew gets bent, not long enough or too long, or if you want to change the pitch of the ones you have.

     
  19. DobryG

    DobryG Member

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    I got new lead screws

    Should get Tr 8*4 (P2)

    But got TR8*8 (P2) it seems

    Look at this, I've found how to determine quick screw lead

    Screenshot_4.png

    Look at the top - it has 4 grooves on the face

    Screenshot_6.png
    Look at its lead, it's 8mm as I measured

    As for TR8*4 it should be 2 grooves on the face

    Am I right?

    P.S. Well with that I will have very little steps by turn to get into 0,1mm accuracy, Think it not suits me
     
  20. WheresWaldo

    WheresWaldo Volunteer ( ͠° ͟ʖ ͡°)
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    Is 40 steps too little? The TR8-8 is 400 steps per mm.
     
    #60 WheresWaldo, Nov 1, 2016
    Last edited: Nov 1, 2016
    danzca6 likes this.

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