Modified metric threads for 3D Printing

[jimDHF63]

I followed the guidance 

And created modified threads with maximum clearance to allow for 3D printing without having to manually move thread faces afterwards.

See https://www.printables.com/model/1008623-metric-bolts-and-nuts-working-threads-with-adjuste/files if you want downloads or more details

Note even these maximum clearance threads will still require ‘breaking in’ so that you cut through the seam positions that will be on your printed threads.  Do this by screwing your nut and bolt together a few times - then it will move freely after that.

1) Autodesk help on creating non-standard threads here  https://www.autodesk.com/support/technical/article/caas/sfdcarticles/sfdcarticles/Custom-Threads-in-...

https://amesweb.info/Screws/metric-thread-dimensions-calculator.aspx to obtain the required dimensions.  Use custom calculation for any diameter and pitch use 6g and 6H clearance for calculations.

2) Then edit the .xml file
For bolts (external threads) I take min major dia, min pitch dia and min minor dia
For Nuts (internal threads) I take max pitch dia and leave major and minor dia as defined
For any combination I was adjusting, I copied the thread specification block and added Max after the name.
 

3) So for example here is the edited block for M12x1.75 (new section shown in bold)
    <Designation>

      <ThreadDesignation>M12x1.75</ThreadDesignation>

      <CTD>M12x1.75</CTD>

      <Pitch>1.75</Pitch>

      <Thread>

        <Gender>external</Gender>

        <Class>6g</Class>

        <MajorDia>11.8335</MajorDia>

        <PitchDia>10.754</PitchDia>

        <MinorDia>9.8365</MinorDia>

      </Thread>

      <Thread>

        <Gender>internal</Gender>

        <Class>6H</Class>

        <MajorDia>12.2265</MajorDia>

        <PitchDia>10.963</PitchDia>

        <MinorDia>10.2735</MinorDia>

        <TapDrill>10.25</TapDrill>

      </Thread>

      <Thread>

        <Gender>external</Gender>

        <Class>6g Max</Class>

        <MajorDia>11.701</MajorDia>

        <PitchDia>10.679</PitchDia>

        <MinorDia>9.601</MinorDia>

      </Thread>

      <Thread>

        <Gender>internal</Gender>

        <Class>6H Max</Class>

        <MajorDia>12.2265</MajorDia>

        <PitchDia>11.063</PitchDia>

        <MinorDia>10.2735</MinorDia>

        <TapDrill>10.25</TapDrill>

      </Thread>

      <Thread>

        <Gender>external</Gender>

        <Class>4g6g</Class>

        <MajorDia>11.8335</MajorDia>

        <PitchDia>10.7815</PitchDia>

        <MinorDia>9.864</MinorDia>

      </Thread>

    </Designation>

Example zipped .xml file included with the threads I adjusted - I will go on to adjust more as and when I need them

4) Thread .xml file has to be placed here on my PC (your location will differ see Autodesk notes above) 
C:\Users\jim\AppData\Local\Autodesk\webdeploy\production\1a197c6e79bef01edef1dc4f317d9f597820e633\Fusion\Server\Fusion\Configuration\ThreadData\ISOMetricprofile.xml

5) Then when you select the thread in Fusion 360, you will now have a new clearance to select which actually models a thread that you can print. (see screenshot)

6) https://wermac.org/bolts/dimensions_hex-nuts_across-flats-and-heights_din-iso.html to obtain nut dimensions across flats (for test pieces)

7) Test designs drawn for:
M3x0.5
M4x0.7
M5x0.8
M6x1.0
M8x1.25
M10x1.5
M12x1.75 and M12x1.25

Models tested in eSun PLA+