Sand got in the retractable handle for the cooler, one side grabbed, and the handle ate itself.

This is the replacement.  Fits perfectly, and seems stronger than the original.

Designed this in OpenSCAD in about an hour, the vast majority of said time spent trying to replicate the hand grip.

STL file rendered in OpenSCAD for use with a 0.4mm nozzle.  If you want to use a different nozzle, change that variable in the source and render it again.  Both are included here.

For that matter, change any variable in the source and most changes should 'just work'.  

The nozzle size matters as the supports for the shaft area are built in and are exactly 1 nozzle wide.

It is setup to print laying down as this will make it stronger in the directions it needs to be.  If you can print decent overhangs, great.  If not, use supports.  As mentioned, supports for the required area where the shaft is inset are already included in the model.

Sliced in Cura with: 

• 0.2mm layer height
• 6 walls
• Alternate extra wall enabled
• Combing All enabled, avoid printed parts disabled
• 8 top/bottom layers
• 30% infill
• 45mm/sec

I also disabled retraction, turned up jog speed to 300mm/sec, over-extruded by 5%, and raised the printing temp by 10 degrees, but that is just what I like to do on structural parts.

I ended up printing it at 1.3x speed so 45mm/sec became about 60mm/sec which was a little too fast for some of the overhangs.  It turned out good enough on the first try that I'm not reprinting it.

It consumed 69 grams of filament.  

I printed mine in PLA which I may regret the first time I leave it in the car on a hot day...  I would suggest something a little more heat resistant, but my heated bed is still offline so... PLA it was.