Astro-threads for Fusion 360

[Paul Gerlach]

I just want to share this with my fellow 3D printing astronomers.
When I designed the 3D printable  LOWSPEC spectrometer, I noticed that threads like T-thread, c-thread, 1.25 inch filter thread and 2 inch filter thread were not present in the thread library of Fusion 360. So I made them myself.

I've included a small xml file that you can download and then drop it in a specific folder. In this link you can read where to drop the file in order for it to work. A word of caution; in this specific path there is a version number that changes every time Fusion 360 gets an update. Now all the standard Fusion threads are automatically  copied to the new location except.... the custom threads 🙄. So be aware that if you can't find them any more it's probably due to a recent update and you'll have to manually move the file yourself.

Applying a thread is easy. You first select the outside or inside of your cylinder shape, go to 'CREATE' and select 'Thread'. In the pop-up menu that appears select 'AstroISOmetric' at the 'Thread' drop-down. Then select the required size thread. In order for it to be 3D printed you should check the box 'Modeled' at the top.

regards,
Paul

AstroISOmetric.xml

[markse68]

Just wondering do such fine threads actually print 3D? 

[Atreta]

 

2 hours ago, markse68 said:

Just wondering do such fine threads actually print 3D? 

I printed a m48 extension tube with an ender 3,  it worked fine.  M42 I've yet to try. 

[ejp1684]

Yes, I've printed threads successfully on a Prusa i3 using 0.1mm layers.

Eric.

[Thalestris24]

Thanks for that Paul I found an xml for a t2/m42 and m48 thread a while back but it disappeared before I got around to trying it .  I still have the file. You'd think Autodesk would make life easier for users...

I've done my best to calibrate the Ender 3 Pro now though I'm still sceptical about its ability to print threads. Anyone know if I can get Cura to slice at 0.1 rather than the 0.12 it seems to insist on? Would it make a difference anyway?

Louise

Edited January 6, 2020 by Thalestris24

[Atreta]

2 hours ago, Thalestris24 said:

Thanks for that Paul I found an xml for a t2/m42 and m48 thread a while back but it disappeared before I got around to trying it .  I still have the file. You'd think Autodesk would make life easier for users...

I've done my best to calibrate the Ender 3 Pro now though I'm still sceptical about its ability to print threads. Anyone know if I can get Cura to slice at 0.1 rather than the 0.12 it seems to insist on? Would it make a difference anyway?

Louise

I use with a regular ender 3,   IIRC  i printed the last m48 extension with a 0.12 layer height and with suuports. 

Cura should allow you to change it to 0.1 with no problem, it's under the quality setting. with the ender you can go all the way down to 0.04 if needed. But the lowest i tried was 0.08.

Edited January 6, 2020 by Atreta

[Paul Gerlach]

Louise,

Make sure that no support is being introduced in between the threads by the slicer. And, of course always print it in the Z-direction.

[Thalestris24]

1 hour ago, Paul Gerlach said:

Louise,

Make sure that no support is being introduced in between the threads by the slicer. And, of course always print it in the Z-direction.

Yes, I do and I do. I've not had occasion to print any .75 pitch threads since the Lowspec - apart from the updated Ovio slit holder which I've printed but not fitted yet.

Cheers

Louise

[frostyfriday]

Thanks for the info Paul.

 

I just printed a great T2 male thread on my Artillery Sidewinder X1 v4

 

By fluke I got it exactly right!

I created the thread in Fusion 360 and then applied a 0.1mm clearance to all surfaces of the thread using "Press/Pull (q)".

I printed at 0.12mm layer height and it worked perfectly.

I made my part such that the threads did not rest on the printer bed to avoid "Elephants foot" on the first few threads. I made the threads at the top of the print so the printer was easily able to print them with no support etc.

I am amazed that the printer can produce such a fine pattern!

-Dennis

 

[AlexK]

Thanks for that, Paul. Even though I've ditched the Fusion360 in favor of OnShape.com simplicity long ago and making all threads by simply spiraling a triangle over the surface 

These threads can be FDM printed indeed after some test prints done to fine tune the sizes, as all plastics are different and often can't match needed tolerances just out of the box on a random printer.
However I would stay away from that possibility at all cost as they will be unreliable if need to be used often. If that's a rare occasion for that thread to be undone then it might be OK if it's not too short (e.g. I would hesitate using it in a filter wheel for example, or with a $3K interchangeable camera lens). Still I would print it undersized and use the heat gun to set it over the mating metal thread semi-permanently.
Fortunately, the 3D Printer at home and free CAD software allows you to avoid using threaded connections in 90% of cases completely. E.g. for a filter wheel you can print filter cassettes and use sturdy spring latches to fix them in place with filters clamped inside.

[tooth_dr]

@Paul Gerlach Hello Paul, thanks for sharing your work.  Can I ask is it possible to adapt the figures to suits a 72mm x 0.75mm thread?  I want to create a OD M72x0.75 thread to screw onto my lens, with an ID M48 thread for a 2" filter.  

[Thalestris24]

8 minutes ago, tooth_dr said:

@Paul Gerlach Hello Paul, thanks for sharing your work.  Can I ask is it possible to adapt the figures to suits a 72mm x 0.75mm thread?  I want to create a OD M72x0.75 thread to screw onto my lens, with an ID M48 thread for a 2" filter.  

Hiya

I think you just need to add your values and label to Paul's xml file above

Louise

[tooth_dr]

8 minutes ago, Thalestris24 said:

Hiya

I think you just need to add your values and label to Paul's xml file above

Louise

Thanks Louise.  I've copied in the M48 thread details to this post.  I thought if I just changed it to 72mm then would work, but from my initial attempt at this, it looks like the thread in inside and not protruding from the OD of my cylinder (if that makes sense).  But I am new to Fusion360 having used it for 1 day in total, so I could be doing something wrong.

 

M48 x 0.75 below

 

<ThreadSize>

    <Size>48</Size>

    <Designation>

      <ThreadDesignation>2 inch filter thread</ThreadDesignation>

      <CTD>2 inch filter thread</CTD>

      <Pitch>0.75</Pitch>

      <Thread>

        <Gender>external</Gender>

        <Class>6g</Class>

        <MajorDia>47.908</MajorDia>

        <PitchDia>47.4409</PitchDia>

        <MinorDia>47.0475</MinorDia>

      </Thread>

      <Thread>

        <Gender>internal</Gender>

        <Class>6H</Class>

        <MajorDia>48.1201</MajorDia>

        <PitchDia>47.5789</PitchDia>

        <MinorDia>47.2831</MinorDia>

        <TapDrill>47.25</TapDrill>

      </Thread>

      <Thread>

        <Gender>external</Gender>

        <Class>4g6g</Class>

        <MajorDia>47.908</MajorDia>

        <PitchDia>47.4594</PitchDia>

        <MinorDia>47.066</MinorDia>

      </Thread>

    </Designation>

</ThreadSize>

 

 

I then changed the 48 to 72, the thread pitch is the same so I thought that this might work?

 

<ThreadSize>

    <Size>72</Size>

    <Designation>

      <ThreadDesignation>2 inch filter thread</ThreadDesignation>

      <CTD>2 inch filter thread</CTD>

      <Pitch>0.75</Pitch>

      <Thread>

        <Gender>external</Gender>

        <Class>6g</Class>

        <MajorDia>71.908</MajorDia>

        <PitchDia>71.4409</PitchDia>

        <MinorDia>71.0475</MinorDia>

      </Thread>

      <Thread>

        <Gender>internal</Gender>

        <Class>6H</Class>

        <MajorDia>72.1201</MajorDia>

        <PitchDia>71.5789</PitchDia>

        <MinorDia>71.2831</MinorDia>

        <TapDrill>71.25</TapDrill>

      </Thread>

      <Thread>

        <Gender>external</Gender>

        <Class>4g6g</Class>

        <MajorDia>71.908</MajorDia>

        <PitchDia>71.4594</PitchDia>

        <MinorDia>71.066</MinorDia>

      </Thread>

    </Designation>

</ThreadSize>

 

 

 

[Thalestris24]

Hi

Here is an example of adding an M49 thread which worked ok  Maybe you can just compare?

Louise

M49x75_Thread.xml

[tooth_dr]

-<ThreadSize>

<Size>49.0</Size>

-<Designation>

<ThreadDesignation>M49x0.75</ThreadDesignation>

<CTD>M49x0.75</CTD>

<Pitch>0.75</Pitch>

-<Thread>

<Gender>external</Gender>

<Class>6g</Class>

<MajorDia>48.908</MajorDia>

<PitchDia>49.4349</PitchDia>

<MinorDia>48.0415</MinorDia>

</Thread>

-<Thread>

<Gender>internal</Gender>

<Class>6H</Class>

<MajorDia>49.1291</MajorDia>

<PitchDia>48.5879</PitchDia>

<MinorDia>48.2831</MinorDia>

<TapDrill>49.25</TapDrill>

</Thread>

-<Thread>

<Gender>external</Gender>

<Class>4g6g</Class>

<MajorDia>48.908</MajorDia>

<PitchDia>48.4554</PitchDia>

<MinorDia>48.062</MinorDia>

</Thread>

</Designation>

</ThreadSize>

</ThreadType>

 

@Thalestris24 I've copied and pasted your and I think I've spotted the error in mine, I've highlighted it in purple.

 

<ThreadSize>

    <Size>72</Size>

    <Designation>

      <ThreadDesignation>2 inch filter thread</ThreadDesignation>

      <CTD>2 inch filter thread</CTD>

      <Pitch>0.75</Pitch>

      <Thread>

        <Gender>external</Gender>

        <Class>6g</Class>

        <MajorDia>71.908</MajorDia>

        <PitchDia>71.4409</PitchDia> this should be 72.4409mm i think.

        <MinorDia>71.0475</MinorDia>

      </Thread>

      <Thread>

        <Gender>internal</Gender>

        <Class>6H</Class>

        <MajorDia>72.1201</MajorDia>

        <PitchDia>71.5789</PitchDia>

        <MinorDia>71.2831</MinorDia>

        <TapDrill>71.25</TapDrill>

      </Thread>

      <Thread>

        <Gender>external</Gender>

        <Class>4g6g</Class>

        <MajorDia>71.908</MajorDia>

        <PitchDia>71.4594</PitchDia>

        <MinorDia>71.066</MinorDia>

      </Thread>

    </Designation>

</ThreadSize>

[Thalestris24]

2 minutes ago, tooth_dr said:

-<ThreadSize>

<Size>49.0</Size>

-<Designation>

<ThreadDesignation>M49x0.75</ThreadDesignation>

<CTD>M49x0.75</CTD>

<Pitch>0.75</Pitch>

-<Thread>

<Gender>external</Gender>

<Class>6g</Class>

<MajorDia>48.908</MajorDia>

<PitchDia>49.4349</PitchDia>

<MinorDia>48.0415</MinorDia>

</Thread>

-<Thread>

<Gender>internal</Gender>

<Class>6H</Class>

<MajorDia>49.1291</MajorDia>

<PitchDia>48.5879</PitchDia>

<MinorDia>48.2831</MinorDia>

<TapDrill>49.25</TapDrill>

</Thread>

-<Thread>

<Gender>external</Gender>

<Class>4g6g</Class>

<MajorDia>48.908</MajorDia>

<PitchDia>48.4554</PitchDia>

<MinorDia>48.062</MinorDia>

</Thread>

</Designation>

</ThreadSize>

</ThreadType>

 

@Thalestris24 I've copied and pasted your and I think I've spotted the error in mine, I've highlighted it in purple.

 

<ThreadSize>

    <Size>72</Size>

    <Designation>

      <ThreadDesignation>2 inch filter thread</ThreadDesignation>

      <CTD>2 inch filter thread</CTD>

      <Pitch>0.75</Pitch>

      <Thread>

        <Gender>external</Gender>

        <Class>6g</Class>

        <MajorDia>71.908</MajorDia>

        <PitchDia>71.4409</PitchDia> this should be 72.4409mm i think.

        <MinorDia>71.0475</MinorDia>

      </Thread>

      <Thread>

        <Gender>internal</Gender>

        <Class>6H</Class>

        <MajorDia>72.1201</MajorDia>

        <PitchDia>71.5789</PitchDia>

        <MinorDia>71.2831</MinorDia>

        <TapDrill>71.25</TapDrill>

      </Thread>

      <Thread>

        <Gender>external</Gender>

        <Class>4g6g</Class>

        <MajorDia>71.908</MajorDia>

        <PitchDia>71.4594</PitchDia>

        <MinorDia>71.066</MinorDia>

      </Thread>

    </Designation>

</ThreadSize>

You should probably change the ThreadDesignation label also

Louise

[tooth_dr]

6 minutes ago, Thalestris24 said:

You should probably change the ThreadDesignation label also

Louise

I will do that too, will be easier to find it in the menus

 

Thanks again for your help Louise.

 

Adam.

[Thalestris24]

28 minutes ago, tooth_dr said:

I will do that too, will be easier to find it in the menus

 

Thanks again for your help Louise.

 

Adam.

I was just thinking I wasn't sure why the labels 'external' and 'internal' are used - 'male' and 'female' would do me!

Also re: tolerances doesn't necessarily take into account your 3d printer precision/variability/stability. I generally have to have several goes on my Ender 3D Pro to get a thread that fits properly, especially with 0.75 pitch (though 1mm pitch is usually ok). So that usually involves adjusting the tolerance values - trial and error! I'm currently trying to upgrade my printer somewhat and firm up the bed. I fitted upgrade springs which helped a lot. Hopefully, once I've made the further improvements it will be a more precise and reproducible printer. If you're fortunate enough to have a better printer, it may not be such a concern. I've looked at different models e.g. the Ender 5 Pro and the CR10S, but I'm not convinced either of them would definitely be better than I already have.

Louise

[tooth_dr]

59 minutes ago, Thalestris24 said:

I was just thinking I wasn't sure why the labels 'external' and 'internal' are used - 'male' and 'female' would do me!

Also re: tolerances doesn't necessarily take into account your 3d printer precision/variability/stability. I generally have to have several goes on my Ender 3D Pro to get a thread that fits properly, especially with 0.75 pitch (though 1mm pitch is usually ok). So that usually involves adjusting the tolerance values - trial and error! I'm currently trying to upgrade my printer somewhat and firm up the bed. I fitted upgrade springs which helped a lot. Hopefully, once I've made the further improvements it will be a more precise and reproducible printer. If you're fortunate enough to have a better printer, it may not be such a concern. I've looked at different models e.g. the Ender 5 Pro and the CR10S, but I'm not convinced either of them would definitely be better than I already have.

Louise

Thanks Louise. I’ll try a print later. I have an Ultimaker 2+ Extended. I’ll set it to 0.1mm layer and see how it fairs.

[tooth_dr]

Still doesnt appear to be working.  I've attached a screenshot.  Do you know what I would be doing wrong here?

 

[Thalestris24]

Hiya

I take it you selected 'modeled' for the external thread? You could use the inspect -> measure in fusion to check the thread measurements. Also maybe try tweaking the values including reducing the base diameter (shouldn't actually be 72, I don't think..). Does what you've printed measure correct? 

We need a mechanical engineer's help here...

Louise

[tooth_dr]

20 minutes ago, Thalestris24 said:

Hiya

I take it you selected 'modeled' for the external thread? You could use the inspect -> measure in fusion to check the thread measurements. Also maybe try tweaking the values including reducing the base diameter (shouldn't actually be 72, I don't think..). Does what you've printed measure correct? 

We need a mechanical engineer's help here...

Louise

Louise

Thanks again, I now have it sorted.  My figures were correct, and the amendments I made in purple were incorrect.  What I did in the end was edit one of the existing Fusion360 thread files and just add my thread details into the existing ISO Metric profile (it went as far as M72x1.0) so now I have M72x0.75.  Now to try printing it tomorrow.

 

All the best

Adam.

 

 

[Thalestris24]

6 minutes ago, tooth_dr said:

Louise

Thanks again, I now have it sorted.  My figures were correct, and the amendments I made in purple were incorrect.  What I did in the end was edit one of the existing Fusion360 thread files and just add my thread details into the existing ISO Metric profile (it went as far as M72x1.0) so now I have M72x0.75.  Now to try printing it tomorrow.

 

All the best

Adam.

 

 

Yeah, I was looking at M72 x 1.0mm on the grounds that the tolerances should be close (enough?). Looks like the base size should be 71mm or maybe a leetle bigger. Hope it prints out ok!

Louise

ps camera filters mostly have a 0.75mm pitch so there should be a spec somewhere...

Edited December 9, 2020 by Thalestris24

[Thalestris24]

i came across this thread calculator which might be generally useful: GewindetoleranzRechner ISO-Gewinde DIN 13 (iso-gewinde.at)

here is M72 x 0.75 I plugged in:

ThreadCalculater.pdf

 

It gives a male thread core diameter of 71.058mm - pretty much what I thought!  

Louise

Edited December 10, 2020 by Thalestris24

[AlexK]

9 hours ago, Thalestris24 said:

Also re: tolerances doesn't necessarily take into account your 3d printer precision/variability/stability. I generally have to have several goes on my Ender 3D Pro to get a thread that fits properly, especially with 0.75 pitch (though 1mm pitch is usually ok). So that usually involves adjusting the tolerance values - trial and error! I'm currently trying to upgrade my printer somewhat and firm up the bed. I fitted upgrade springs which helped a lot. Hopefully, once I've made the further improvements it will be a more precise and reproducible printer. If you're fortunate enough to have a better printer, it may not be such a concern. I've looked at different models e.g. the Ender 5 Pro and the CR10S, but I'm not convinced either of them would definitely be better than I already have.

Exactly. The actual problem is not the printer but the filament. Even from the same vendor the same filament type may print different between batches. Add to that the hygroscopic nature of almost every filament, which means it may print different after a day of sitting open on the spool rollers. I would recommend simply learning your particular printer quirks (Ender-3 is a good modern enough choice for tinkering at home no doubt) and test-printing each new filament you get. With experience you will know at once how to adjust your model or slicer to fix any issues (or use them to your advantage). I'm personally never expecting my prints sub-millimeter perfect, thus keeping a toolset of precision woodworking chisels,  Dremel bits, and the fine soldering work heat gun at hand.