Hey, I’m looking to start making a set of press-fit pulleys for the OG 5 spoke hoyt 5-inch pneumatics. I was wondering if anyone had a copy of the AutoCAD style drawing of them that was listed on their website when they went on sale. I know its kinda a stretch, but thanks in advance!
Nevermind, I found the file in wayback machine. I’ll post the files here if/when I make the pulleys.
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So - how did it work? I need those pulleys and will design my own… Except somebody else did it before.
Kinda stopped working on the project bec I couldn’t get the gear teeth right. I’ll post the schematics of the OG Hoyt 5s and can post what I have as a STEP file and Solidworks file. I had just figured out how to make them work with the stock pulleys and kinda abandoned the project.
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It would be great to be able to work with your template. Much easier than starting from scratch.
This should be everything you need!
hoyt5pulleys.SLDPRT (527.4 KB)
hoyt5pulleys.STEP (708.7 KB)
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not entirely sure if they fit becuase I couldn’t get it completely sorted out before I figured out how to make them work with the stock pulleys, but its pretty close and should be a good starting point.
Thanks man! Appreciate it.
I will work on those this week. Probably starting with printing your version to have a look at the fitting.
I will post my results here.
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Getting closer. Already a nice fit on the Hoyt 5" but still some tweeking before they fit my DKPs.
After that I will do some different numbers of teeth. This is 32T for no reason. Will more likely need something ~40T.
I bought PAHT-CF and PA6-CF filament for the pulleys. There is no perfect orientation in FDM printing for this part… maybe order SLS parts in PA12?
I think I start by just trying this prototyps in PETG and see how long they last. I think the smaller the radius (fewer teeth), the less long the parts will last.
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Hey. Those look awesome. You think i can order 3sets. 32t works for me, but I can do 40t. Lmk
Thanks in Advance.
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I would not feel well with selling questionable quality 3D printed pulleys. Sorry. The possibility of someone crashing because of a not suitable design/manufacturing would give me some real nightmares.
Maybe we find some more people interested? Then we could do a group buy of CNC parts in aluminium.
Edit: Glad to hear you like my design!
Thanks fer Fast Response. “Classy”.
Understood….appreciate ur deep “Considerations” At 61 I have a Good Grasp of how Im putting my Cojones on the Board…… with that said, Arent we all just crash test dummies… waitin for something to go “mechanically wrong at any given time….
Nothing is perfect…… i have a WHOLE list of “Malfunctions too long to list.
Ur design was/is Genius. Simple lightweight, bc of heat, prob better on belts too. Of course i dont know enough about materials used to make Your “pulleys”
Interesting that you dont have enough confidence in ur design to move forward. Id like to pick ur brain and 1st hand experience more. Why aluminum? That sounds pricey. If plastics are use now, there must be reasons…
Either way……PUT ME ON DATT BUKKIN LIST !!!
Ima NEED 6x sets !!! Lol
Be Well
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They will be significantly weaker than injection molded parts.
The 3D printed parts are made out of materials mostly made for good printing process. PLA, PETG etc is not “engineering grade” plastics.
Mechanical properties will be anisotropic… like a lot. Especially in z-direction of the printing process.
Even if you use fiber filled filaments of types like ABS, PA etc. and you would get the very best layer adhesion one can hope for, the parts would still be anisotropic because of the fiber orientation.
Injection molding uses a shit ton of force to press the hot melted plastic in a mold resulting in high density and (mostly) isotropic behaviour.
One could always get them CNC out of plastics. But with CNCing the price for the part mostly consists of machining time. So for a very small amount of money more you can get them out of Aluminium instead of e.g. ABS.
I trust my design. I trust 3D printing. And I trust CNC machining. But everything serves its purpose in a different way.
Long answer short: If you want some Aluminium parts it will most likely be about 80€ per piece and will take about 4 weeks depending where you live.
P.S.: Why would one person need 6 sets (12 parts)? 
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Has anyone actually tested this? I think 3D printed pulleys would get hot and then get soft during a long ride or hard climb.
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I think it will need some more temperature and abrasion resistive stuff like PA
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This is a good read for this topic
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