Wingnut for battery compartment cover for Toyota Avensis (2004) T4 2.4 Litre but probably many other models too.

My Toyota Avensis battery compartment cover has a badly made plastic wingnut which I think is designed to be shoved on in the factory for sheer speed, and then unscrewed to remove. The only contact between the nut and the threaded shaft it has to hold onto is from two little pointed edges of the central tabs, and it should have been obvious to the designer that this would survive only a few removals before becoming ineffective. Mine broke the first time it was removed by the garage. I've been meaning to mend it somehow for 17 years, hahaha, I just didn't get a round tuit.

Then I bought an Elegoo Neptune3 Pro, and my life changed :o)

Being a complete noob to CAD, my first attempt was based on finding a steel nut in a box of bits which happened to fit the threaded rod sticking out of the battery compartment. So I designed a new wingnut around that nut and glued it in. Worked perfectly. So I made it parametric for the nut size in the F3D file - if you can find a nut that's the right size (it's actually M6-1 which is 6mm outer thread diameter and 1mm thread pitch) you can Modify/fx Parameters and change the flat-to-flat diameter of your nut and the face-face height of your nut, print the wingnut and glue your nut into it with e.g. epoxy resin. Job done!

Then I discovered that Fusion360 has standard threads built in, YAY! So I redesigned it with an M6-1 thread and printed it out. Again it was perfect!

So now you have a choice, find a nut and use the parametric version, or just print the threaded one. I've included both F3D files and both the STLs, the parametric nut STL is for a 10mm x 5mm nut (set to 10.5mm to give a little space for the glue). Line up the threaded one carefully the first time you screw it on - you don't want to crossthread it, after that it'll find its own way and not be quite so tight, it's a good snug fit.

 Recommendations for printing - 

• Layer Height - 0.2mm for the nut version, 0.12 for threaded to optimise the thread
• Walls - 3 at least
• Top/bottom thickness - 1.2mm at least
• Infill - 20% - Zigzag seems to support the central section best
• Support - none needed
• Retract - yes
• Print Speed - 60mm/s
• Adhesion - skirt only (just to make really sure the nozzle is spotless)
• Material - anything really, maybe not TPU hehehe, I used PLA+

I did have a look online for a replacement original, not that I would have bought one becuase it's so poorly designed - the only one I could find was priced at £10 and I didn't even look to see what the P&P was on top of that! Mine costs about 10p to print, so that's 1/100 of the price of an inferior new one. I hope this helps others with the same problem :o)

I've included photos of both versions sitting next to the threaded pillar in my car, and the nut version in place on the pillar. Also a slice photo (Cura) showing the nice infill pattern of zigzag and the visible threads. And the original Toyota wingnut just so you can laugh at it :o) 

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