Drawing sprockets?


I, too, have been working to create a sprocket for 8mm film. I started with OpenScad as I like the programmatic way of creating shapes, but I felt there were some limitations. So I tried the Fusion 360 API.

I wrote a Python script within Fusion 360 to build a sprocket of any number of teeth. It was created to deal with standard 8mm film dimensions but could be easily modified for other formats as the sizes aren’t hard coded.

Unfortunately, as I don’t own a 3D printer, I haven’t experimented with producing a sprocket. I had a sprocket printed by a friend but the result was not usable; the teeth became blobs, possibly because they aren’t supported in the printing process, or maybe the material wasn’t suitable (abs or pla?).

If anyone wants to use the script to print a sprocket, please do, and show and describe the result.

Sorry, I tried to upload some images and the script, but as a new user I was prevented.

Here are two examples of the sprockets generated:

As uploading Python scripts is prevented, I have created a PDF version that could be copied into a text editor and then to Fusion360 using: Tools/Add-Ins/Scripts and Add-ins/Create. VSCode should appear and allow the script to be pasted, saved and run.

I’m hoping someone will find the script useful, print a sprocket and report.
make_sprocket005.pdf (233.4 KB)
Updated: Link to github


I’d be happy to try printing your model for you @rohal. Do you have an STL file?

@rohal, just as a feedback: I have tried to print Super-8 sprockets with my 200€ Anet A8 FDM printer. This printer simply does not have the resolution to print sprockets for such small dimensions.

However, I ordered this part here:

from Shapeways. This is printed by not by the FDM method but by the SLA method which features a much finer resolution, so it actually works.

Great. Thank you.

Can I upload an STL? Or email?

Yes I have seen that sprocket and it was my original inspiration to investigate sprockets.

Thanks for the feedback.

You can email me: matthewepler at gmail.com

Thanks; consider it done

@rohal here are the results. This was printed on a Prusa MK3 with PLA on a “draft” setting, meaning it isn’t the finest possible detail. The print took 1.5 hours.

In my humble opinion, it would seem like the sprockets might need to be less sloped. When I tried to fit a piece of film onto the roller, the sprockets were unable to come through all the way because they were too wide at the base.

Thank you https://forums.kinograph.cc/u/matthewepler

The result is quite good. I think the ‘wide’ teeth are a result of the printing process, where the transformation between the tooth profile and the roller body is not a tight angle, more of a fillet? Greater resolution might help here?

I would be curious to know the radius of the roller body.

I am not in a position, at the moment, to experiment with 3d printing, however the SLA method, mentioned above, might be worth looking into.

I also had the idea of assembling the sprocket from separate roller and teeth parts. The teeth base would be at a smaller radius than the roller, allowing the fillet transition to occur below the roller radius.
For example the teeth could be printed as:

Once again, thank you for the printing.

Just a heads up for any one using an SLA (resin) 3d printer if you sprokets do not fit the film it’s probobly because the printer is not 100% calibrated, i made my Sproket design and then made 4 seperat sproket wheels and lowerd size each one by 0.5% untill i had one that i could wrap film all the way around.

Should note the big wheel your trying to make would not fit in most SLA printers

Wow nice -never thought you could print super8 sprockets -Think these could be cnc cut using a 1mm end mill out of thin 1mm or .5mm aluminium sheet - then mount it in a printed or lathed ali hub.


that looks great! congrats.

What printer is that on -I want one

@MrCapri, said in this 8mm/super 8mm scanner thread that it’s an creality ld-002r. A very good printer, especially at this price point.

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I dont know if i can upload OBJ of the sprokets here but i would absolutly be willing to

Thanks, i’m realy happy whit how the sproket turned out

Looks great - ya can post em on thingiverse if want

https://www.thingiverse.com/thing:4548639 8mm spoket (name on this is wrong sorry)

https://www.thingiverse.com/thing:4548640 super 8mm sproket

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