When I purchased my 2017 Ford Focus ST the dealer had not mounted the front license plate bracket. After a quick Google search revealed my state of NJ required a front license plate, I snapped the stock front bracket into the appropriate holes but did not drill any holes or used any screws to secure the bracket to the body of the car. I stood back and cringed at how the center mounted plate diminished the aggressive look of my new car. Later that day I drove about 50 miles and when I got home the stock bracket along with my license plate was gone! After waiting in line at the DMV and paying $7 for new plates, and finding no alternative brackets online, I decided to try and design my own bracket that could be fully secured, WITHOUT drilling holes in the bumper and did not take away from the look of the car. This 3D printed design does exactly that and can be installed without removing the grill.
Due to the lack of competenent parallel parkers in my community my mount has been broken three times. All three times were due to drivers hitting my car while they were parking theirs, the mount has never failed while driving or for any other reason other than a direct impact from another vehicle. All three times it was the connecting rod that snapped, no other parts were damaged and no marks were left on the car.
With this in mind I HIGHLY suggest creating a zip tie anchor. Furthermore I now keep a pair of cutters I can use to clip the zip tie in my glove box so if I ever do find the plate dangling I can take the plate + holder off until I can repair the mount. You can even go a step furthur and keep spare connecting rods and an alan key in your car to do a field repair.
I have thought about redesigning the mount to increase strength and rigidity, but I actually found these incidents enlightening as the connecting rod served as a 'break-away' part and by failing can actually prevent damage to the car. If the connecting rod was stronger, it is conceivable these impacts would have put more stress on the gril and increased the likelyhood of damaging the grill or body of the car.
Because all of the parts will be exposed to the elements I recommend printing all parts in ABS plastic to ensure none of them fail due to exposure to the sun.
I printed all my parts with 100% infill to make them as strong as possible, but if you are trying to ration your plastic you can adjust as needed. I would always go with 100% infill on the Connecting Rod as that is the weakest link in the assembly.
None of the parts require support material, but you may need to rotate them in Matter Control to orient them properly.
The License Mount is suceptible to curling up off the bed. I used a heavy amount of Elmers Glue Stick to try and prevent this, although minor curling won't prevent the mount from working.
The entire bracket can be assembled using two M3 screws and self locking nuts. I used four M3 washers as well.
To mount your license plate you will need self tapping screws that are no longer than 2cm and .5cm diameter (including the thread).
The bottom left cylindrical dome will make contact with the body of your vehicle, to prevent scratching I domed the end, but I recommend placing some rubber or felt end on it just to be safe. I used the rubber end of a cane I found at ACE, but can also be found here:
This fit nicely and I secured it with a bit of glue.
Place the Grill Plug in the grill hole indicated in the photos and use two Grill Hooks on the top and the bottom to reach around and secure the plug in place.
Insert the connecting rod into the Grill Plug so the screw holes line up. If you are confused which way make sure the end that is flat passes through the Grill Plug.
Use one M3 screw along with two M3 washers to secure all four pieces together. You may find it easier to pass the screw through the bottom opposed to the top. Use a M3 self locking nut to secure it.
Mount your license plate to the License Mount using self tapping screws, and place your rubber or felt tip of choice on the appropriate corner.
Slide the License Mount on to the connecting rod and secure it with one M3 screw, two M3 washers, and a M3 self locking nut.
A Special Note
Just to be safe I attached a zip tie through the grill and anchored it directly to the License Mount. This is just an extra precaution in case the Connecting Rod snaps, that way I won't lose the License Plate and have to wait in line at the DMV to get new ones.
Works very well and accomplished exactly what I set out to do. The roads in my area are pretty bad but the bracket has held up fine. The rubber cane tip I am using has not fallen off or left any scuffs on the paint. The plate only obstructs the left most column of the open grill holes and those are not even the ones directly in front of the radiator so air flow is not obstructed. I don't use automated car washes but that may be something to watch out for.
This bracket should allow you to use a license plate frame of your choice, currently I am not using one but may get one in the future. There is a bit of flimsyness in the bracket since it only has one mounting point, my only concern would be that adding additional weight to the mount could put more stress on the Connecting Rod and make this worse.
In the future I may edit the Connecting Rod to include an open channel which I could slide three stainless steel rods through for added strength and rigidity