heinzboehmer's 2002 Topaz 6MT Coupe

[heinzboehmer]

Clearances looking good, ready for a test fit:

And finally, ran some quotes and the one that made the most sense was right around $950 all in for 6061-T6 (materials, labor, taxes, shipping, etc.) and $1000 for 7075-T6. $50 extra for 7075? Uh, yes please!

Couple things I should also mention:

Some fab shops (the type that seem to sponsor every single electronics-related youtube video) are way, WAY cheaper than others. Like $300 for everything, it's insane. However, none of these cheap vendors specify T6 for their materials, so who knows what they're using. I think I'm not gonna risk it and instead I'll go with a vendor that tells me the exact material composition of what I'll be getting.

Also, I ran some quick quotes to compare cost for the laser cut + machined version of the windshield piece I briefly discussed above. Bottom line is that I don't think it's worth it, unless you're good at welding aluminum.

For 7075-T6:

• Machined in one piece: $641.42
• Multiple pieces: $409.49 (machined main body) + $40.25 (laser cut bottom sheet) + ~$100 (welding + machining bottom flat labor) = $549.74

So roughly $100 less for the windshield piece if you go the multiple piece route. Even less if you use a cheaper vendor for the machining. I'm personally gonna stick to the fully machined version. Yes, it seems a little crazy to carve away that much material for the flat part, but the extra overhead involved with the other approach is not worth the $100 saved for me.

All this is to say that you could technically get this all made for <$300, but I'm not going to.

[heinzboehmer]

Did what George Hill suggested and ran the analysis on the earliest version possible. Note that this version is actually fairly recent, but unfortunately, I hadn't modeled the brace attachment point in any previous versions. Previous ones did not have the fasteners in line with the load paths, so they would have definitely performed worse.

I'm not gonna show all the cases like I did before cause it's gonna cause a bunch more clutter. Instead, I'll show the worst one, which turned out to be the "one tension, one compression" case. Material was set to 6061-T6 for all of the following.

Stresses:




Piece that attaches to the windshield is still alright, which isn't super surprising, as this was one of the overkill versions. The other piece is definitely not alright, though! Max stress is higher than the yield strength of 6061.

Safety factor:




Same story here, windshield piece is fine, attachment point is not. 0.87 is not good.

Definitely cool to see the progress!