Didn't have the smoothest time at the shop today, but let's start with what went well.
Fixture was super useful. Still requires a bit of creative hold down clamp placement for milling the bottom surface, but it's much better than before. The best part is how easy it is to mill down the surfaces under the nut flanges. Sides of the fixture are parallel to the slots, so just need to throw the assembly on the mill, find the center of the slot, then run the x-axis back and forth.
Quick before and after on one of the slots. You can see the witness marks from my test fit the other day in the before pic:


Only had to remove around 0.3 mm of material to get the surface flat. Happy with that.
Got through four slots aaaand then I was a dumbass:


I'm totally fine, but yeah, made the dumbest of mistakes to make on a mill. Ten points to the first person that correctly guesses what I did.
Anyway, with the mill broken, I wasn't able to machine the bottom surface flat, so I decided to clean the surface up on the belt sander instead. Came out great, not sure the hassle of setting it up in the mill is worth it:

I then went to press in the M10 studs and found the hydraulic press broken...
Sigh, arbor press it is.
At this point, I was feeling a bit defeated by the shop, so I half-assedly sanded the mounting surfaces for the braces and went home:

As mentioned earlier, this post processing is likely not all that necessary, given the quality of the surface. But to drive the point home, here's the surface on the 3D printed part next to the stock BMW cast part:

And finally, I threw the brackets on the car to put them to the test before they go for paint:

M10 studs torqued up no problem, so seems like the arbor press did its job. Worth noting that I did slightly decrease the size of the holes that the studs press into compared to the holes in the windshield mount, so that might have also played a role. Will carry that change over to the design of the windshield mount.
I'll do my best to put some miles on the car this week. Am also signed up for a laguna track day (lots of bumpy kerbs) next weekend, so that should be a good torture test for these parts.
Fixture was super useful. Still requires a bit of creative hold down clamp placement for milling the bottom surface, but it's much better than before. The best part is how easy it is to mill down the surfaces under the nut flanges. Sides of the fixture are parallel to the slots, so just need to throw the assembly on the mill, find the center of the slot, then run the x-axis back and forth.
Quick before and after on one of the slots. You can see the witness marks from my test fit the other day in the before pic:
Only had to remove around 0.3 mm of material to get the surface flat. Happy with that.
Got through four slots aaaand then I was a dumbass:
I'm totally fine, but yeah, made the dumbest of mistakes to make on a mill. Ten points to the first person that correctly guesses what I did.
Anyway, with the mill broken, I wasn't able to machine the bottom surface flat, so I decided to clean the surface up on the belt sander instead. Came out great, not sure the hassle of setting it up in the mill is worth it:
I then went to press in the M10 studs and found the hydraulic press broken...
Sigh, arbor press it is.
At this point, I was feeling a bit defeated by the shop, so I half-assedly sanded the mounting surfaces for the braces and went home:
As mentioned earlier, this post processing is likely not all that necessary, given the quality of the surface. But to drive the point home, here's the surface on the 3D printed part next to the stock BMW cast part:
And finally, I threw the brackets on the car to put them to the test before they go for paint:
M10 studs torqued up no problem, so seems like the arbor press did its job. Worth noting that I did slightly decrease the size of the holes that the studs press into compared to the holes in the windshield mount, so that might have also played a role. Will carry that change over to the design of the windshield mount.
I'll do my best to put some miles on the car this week. Am also signed up for a laguna track day (lots of bumpy kerbs) next weekend, so that should be a good torture test for these parts.

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