Creating a Timing Belt Pulley in FreeCAD

[@hardwareful]

Was about to use OpenSCAD to create the pulley, then just import the result. I totally overlooked that the Gear WB has it. Stright to the point, thanks

[@chrishayes5755]

You're a very good teacher. Thanks for this tutorial.
FreeCAD is confusing. Always run into issues like why I couldn't POCKET the hole right into the part - it gives some strange error so I followed your technique.

[@Erlorn09]

Thanks a lot!

[@InterCat-xn4iq]

Great, helped me a lot! thx

[@jayfrickel9973]

Thank you very much!
I try for 4 hours now with just one simple bore in the center instead of al that complicated holes you did. Unfortunately every time i try to substract the exctruded cylinder from the fusion (gear and 2 disks) some strange things happens: the GT2 and the bottom disk have the bore, but the upper disc is still without the bore. Whe I selct the fusion before the substraction the upper disk is marked somehow different.
Any advise? (Edit: Freecad Version 0.21.2)

[@depthoffocusmike]

Fun!
But you've gone about this rather the long way round, I think, by switching between workbenches.
You can do absolutely all of this inside Part Design except for the gear (in fact maybe that too -- I don't know much about Part Design's gear and sprocket tools, or timing gears in general).
And you can make use of the Array and Hole tools to simplify cutting the holes (and a tiny bit of trig so you only need one hole and less/no construction geometry per sketch)
I've run through this and made a version I could email you, but I might try to make a quick video...

[@aaronpinder8624]

Thanks for the input!
I actually made this for a friend to demonstrate how CAD works in general, so I wanted to use the classic sketch / constraint method to create the model. You're definitely right that this could have been done more efficiently the way you describe.
Cheers!

[@depthoffocusmike]

@@aaronpinder8624 you still use the sketch/constraint stuff, of course (you don't get as good a demo of construction geometry mind you!) but you have the advantage of staying inside the Part Design flow.
As a rule I would not mix Part and Part Design if I could avoid it, because it gets confusing/weird. It's like the number one thing people don't get about FreeCAD, isn't it -- that there are these two disciplines, one open and one tightly integrated.
If you have an active Part Design Body the gears workbench will even drop the gear straight into it. I didn't realise this until I started working through; my first go-through used the gear as a BaseFeature, which is a bit more annoying to position.
Anyway... having been enormously frustrated by some of the, er, wobblier changes between 0.20.2 and 0.21 on the Mac, here is a video of what I mean:
(edit: see video below)
It does show you how slow the Part Design Hole thread generation is; the ThreadProfile workbench is much faster.
I generally attach sketches to the base planes and then place them (parametrically) rather than attaching them to the faces, because it prevents the Topological Naming Problem from biting me on the behind.

[@depthoffocusmike]

@@aaronpinder8624 I had another go at this (it's addictive isn't it).
th-cam.com/video/V-B4Vv3_Oc4/w-d-xo.html
So this one does use a datum plane to locate the holes (which is much quicker and keeps the parametric element in one place).
And there are a couple of other tidyups in the expressions and I've only got the one polar pattern for the holes, which is quicker.

[@skutahuniai4830]

Good video dude but please up your volume.