E86 Front Triangulation Braces Retrofit

[karter16]

Or a hex head bolt with a pill shape for it? No need to mill a hex shape right? Just two flat sides to stop the bolt head rotating?


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[heinzboehmer]

Why not just tap and put a helicoil in then thread a cap head bolt into the hole with some loctite. Seems easy enough if there’s enough depth in the counterbore.

Mostly for serviceability. Getting a bolt threaded in back there is harder than a nut.

I guess you could tap and thread in a stud, but at that point, the captive bolt approach is not that much more work.

Edit: Oh wait, I think I misunderstood this. Thought you were talking about threading a bolt in from below. Either this or karter16's flats suggestion would work, you barely need any force to hold the fastener in place before friction takes over.

[heinzboehmer]

Or a hex head bolt with a pill shape for it? No need to mill a hex shape right? Just two flat sides to stop the bolt head rotating?


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Oh yeah, duh. That would totally work and is way simpler

[karter16]

Oh yeah, duh. That would totally work and is way simpler

Something like this should be fine right? Obviously I haven't done FEA on it, but I did go through all your screenshots and don't believe this design impacts the areas of highest stress. I'm also not particularly stressed if it does prove to be a problem as easily swapped out if there are any issues.

[Bry5on]

I mean thread a bolt in in place of a stud, not a bolt to replace a nut. I think adding the flats is no better than adding a hex pattern personally. Either way it’s a printed part job. Seems easier to add threads there and eliminate all semblance of a press fit. Just bolt a bolt in instead of pressing a stud..

[karter16]

I mean thread a bolt in in place of a stud, not a bolt to replace a nut. I think adding the flats is no better than adding a hex pattern personally. Either way it's a printed part job. Seems easier to add threads there and eliminate all semblance of a press fit. Just bolt a bolt in instead of pressing a stud..

What is it about the flats that makes it a printed part job? I don't see how it's different from a manufacturing perspective to the circular pocket Heinz has in the current design?


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[Bry5on]

What is it about the flats that makes it a printed part job? I don't see how it's different from a manufacturing perspective to the circular pocket Heinz has in the current design?


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Very easy to machine/drill a circle/cylinder, not so easy to machine an arc to flat transition, especially if you are short on packaging space and need a tight radius on the transition from arc to flat. You’ve gotta think about what tool(s) you’d use to make that part. A tap and hole is about as simple as it gets

[heinzboehmer]

Something like this should be fine right? Obviously I haven't done FEA on it, but I did go through all your screenshots and don't believe this design impacts the areas of highest stress. I'm also not particularly stressed if it does prove to be a problem as easily swapped out if there are any issues.

Bryson spoke to this already, but the problem lies with the sharp corners. Elongating the bore and adding transition fillets would help.

The issue I see with printing this is that the machined mating surface on the windshield mount is super smooth and flat. If printing, I would add material to the E86 attachment point and mill it down so it's also flat.

[karter16]

Of course, thanks both, I'm a bit dumb.

I envisaged one thing - a slot cut with a (virtual) 17mm end mill, and then designed something completely different.

This version takes my actual original plan and improves on it by reducing the amount of extra material removed. a 17.2mm x 20mm pocket, with 10mm sides that hold the bolt head, suitable for a 6mm end mill. Note that the shape is intentionally not a regular hexagon as this design only intends to hold the bolt head on two sides.