Thule Rack Cover with hold-down screw

I've modified ByTwoWheels' good model of the cover so that it can be secured in place with a screw.  The screw needs to be metric 10x1.5 thread, and should be no longer than 17mm in thread length. 

I've included a couple different screws that can be printed: 

One screw uses a 4mm allen key (same as included with the Thule rack) and sits flush with the cover once screwed in.  This one should be printed horizontally with supports on the build plate so that it's strong and you don't have trouble with it sticking to the plate.

The other screw has a 17mm hex head so that you can easily screw it in or take it out by hand.  You can print it vertically with no supports but you'll have to be very careful not to apply any torque when using the screw so that it doesn't break.

The cover itself does not need any supports when printing.

I printed these in PLA, but I'm not sure how long that will last.  Will update if it leads to trouble.

added screw hole (and screw) to secure cover from slipping off once in place