Anyone out there design your own chainrings? What was your process?
Long time lurker, first time caller. I’m in the process of designing some 50.4 BCD chainrings, planning on having them CNCd out of stainless steel. I’m wondering if anyone has some tips and tricks for drawing the tooth profiles and any other design considerations that should be made? So far, I’ve gathered that a bike chain is ANSI 40, and 1/2" pitch. I primarily use Rhino for 3d/2d modeling and I have Fusion360 but I have no clue how to use it yet This is the guide that I followed a while back but had a little trouble at the later stages, the end result looked a little off… http://www.gearseds.com/files/design_draw_sprocket_5.pdf
Not sure if this is helpful, but Paul Brodie recently made a 52-tooth chainring on his Youtube channel. Maybe there are some useful pointers in there…?
This won’t get you all the way, but McMaster-Carr offers tons of components in different CAD formats. If you want to look at a 50T ANSI 40 sprocket as a reference, for example, you can download the appropriate file!
Fusion 360 can open a ton of file types. You could still pull relevant dimensions off a solid model even if it isn’t native to Fusion.
I found some info from a Cycling Tips article
“SRAM chains are one clear exception to using these suggested tools. Most chains on the market start with a roller that’s 7.63-7.65mm in outside diameter. SRAM’s chains are larger — for example, rollers from a Red 22 chain are 7.69-7.70mm, while an Eagle 12-speed chain uses rollers that measure 7.72mm. And SRAM’s new Flat-Top chain as part of the Road AXS groups is larger again (7.90mm).”
Unfortuately, I haven’t found the source article for this quote. But this can help in your design efforts.
The other note I have is that chain plate thickness on most 12 speed chains is identical. There is one really annoying caveat here. The Shimano 12 speed quick link has thicker plates that use more inner space between the plates than other quick links or chains. So if designing a narrow wide chainring, the wide tooth will have to be narrower than it needs to be so that it does not interfere with the shimano 12 speed quick link.
I do also have a Solidworks .sldprt file which may be more configurable, but don’t have access to SW anymore, and it’s not a file type supported for uploading here).
This is the guide that I followed a while back but had a little trouble at the later stages, the end result looked a little off… http://www.gearseds.com/files/design_draw_sprocket_5.pdf
