- Types of License Plate Screw Heads
- US Threads Per Inch Vs Metric Thread Pitch
- License Plate Screw Size for Different Vehicles
- How to Remove Rusted License Plate Screws
- How to Fix Damaged Threads
License plates are plastic or metal plates that are screwed onto your car. But is that all there is to license plates? They have one important job, which is to identify your vehicle.
If you’ve had your license plates for a long time, eventually you may end up with some rusted or worn-out screws, which need to be replaced. But… do you know which license plate screw size you need for your vehicle?
In today’s post, we will go through different registration plate screw sizes and help you find the exact match for your car.
Types of License Plate Screw Heads
License plate screws can be classified by the shape of their heads. The following are the most common types of heads in the industry.
This is a very common license plate screw head. It has a rounded head shape and a fairly large diameter. It sits on top of the surface but the top of the head is flat rather than half-round. The flat underside provides a larger surface area for a stronger hold.
The drive slot of a pan head screw is deep, allowing for increased torque. These screws are commonly available with cross-recessed heads. Slotted and Phillip pan heads have a gently rounded or flat top surface, a flat bearing surface, and cylindrical sides. You can use a Phillips screwdriver to drive this type of screw head.
This type of screw has a low domed-shaped head and a wider bearing surface. Button head screws have a unique finished appearance, which provides a more visually aesthetic look. They have a fairly large head diameter, allowing you to use a larger drive to exert more torque. The button head design doesn’t have pointed edges, making these screws safer to use.
Hex head license plate screws have a hexagonal-shaped head. This type of head can be tightened with a socket or wrench. There are some hex head screws that are fitted with a Phillips or slotted head, allowing you to use a screwdriver instead of a socket or a wrench. These screws may have a flanged head or full-bearing washer. Socket head screws are more like hex head screws but you will need an internal wrench for tightening.
This type of screw has either a countersunk or cone-shaped bottom and a flat top. The head can be aligned below or flush the surrounding surface. Flathead screws are available with different drivers, depending on the size and material. The most common drivers are Phillips, slotted, and socket.
A round head screw has a semi-elliptical top surface along with a flat bearing surface. Roundhead screws are capable of maintaining good connections. One of their most notable advantages is the broad dome-shaped head. This feature is effective for evenly distributing force, eliminating the need for a washer.
Truss head screws come equipped with a low rounded top along with a flat bearing surface that has a larger area than a round head screw of the same size. Truss head profile provides a trim finished assembly appearance. These screws are mostly used in applications where there is limited clearance above the head.
US Threads Per Inch Vs Metric Thread Pitch
US and metric thread pitch are two different things.
US Threads Per Inch
The US threads per inch refer to how many threads are in one inch of the thread area. So, when you read a screw that says 1/4-14 x 3/4, that means a quarter-inch diameter, 14 threads per inch (TPI), and three-quarter-inch long. The length of the screw is usually measured from under the head to the end of the screw.
You can measure threads per inch of a screw by placing a standard scale on the crests of the threads that are parallel to the axis. Then count the number of full threads within one inch of the scale. But, if only part of an inch of stock is threaded, then count the number of full threads in one-half inch and multiply by two to determine thread per inch.
The pitch of any screw thread, irrespective of its thread profile or form, refers to the distance from one point on a thread to the equivalent point on the adjacent thread. In other words, the thread pitch is the distance between the peaks in millimeters.
So, when you read a metric screw size (like M2-0.4 x 5M), the M2 is the diameter, 0.4 is the thread pitch, and 5 is the length in millimeters. There are thread pitch standards for different license plate screw thread sizes.
License Plate Screw Size for Different Vehicles
Here is our complete roundup of screw sizes for license platesof different vehicles:
The screws that are recommended for BMW are very similar to the ones used on Audi. The typical license plate screw size for BMW is about 10 mm long. But they can be as short as 8 mm or as long as 12 mm.
A guaranteed size, however, for a plate with no frame would be M5-0.8 x 8 mm (M5x8) and M5-0.8 x 12 mm for a plate with a frame.
Most BMW screws have a pan head, providing a large mating area for a solid hold. They have a Phillips drive system that is self-centering. They are also made of heavy-duty 18-8 stainless steel for strength and rust protection.
The standard size for Ford F-150 license plate screws is 1/4-14-5/8. The threaded diameter for this size is 1/4 inch, threads per inch are 14, and the length is 5/8 inch. Most screws feature a hex head with a slotted external hex drive system. You will only need a flathead screwdriver for do-it-yourself installation.
With the slotted hex head, you can use greater torque for superior fastening. Made of premium stainless steel, most Ford F-150 registration plate screws can resist rusting for as long as OEM screws. These screws are also available in chrome and black zinc finish.
The correct size when looking for Nissan number plate screws is 1/4-14-3/4. This screw size translates to 1/4 inch threaded diameter, 14 TPI, and 3/4 inches long.
You should consider extended-length screws if you are planning to install a license plate holder, as well. The screw sizes available for Nissan usually have a pan head with a Phillips drive system.
We recommend you only use the Phillips screwdriver to avoid damaging the drive system. You should also look for license plate screws that are designed and factory-made to the highest standards for added durability and maximum performance.
If you have a Chevrolet, you will need 1/4-14 x 3/4 screw size. You can look for either hex or truss head screws. The hex head style has a slotted drive system that can be operated with a standard screwdriver. The truss head style, on the other hand, has a Phillips drive system that can be operated with a Phillips screwdriver.
The best quality screws are normally made of 18-8 stainless steel for superior rust-proof performance. Most of these screws have a self-tapping design, which allows for a perfect fitment for both rear and front license plate mounting.
Toyota license plate screws are engineered to be used either on the rear or front frame. The standard screw size for mounting Toyota license plates is 0.5 x 0.75 x 0.5. When compared to the OEM fasteners, these aftermarket screws have a slightly larger diameter. This helps to hold the license plate firmly in place.
The stock fasteners rust easily and drip corrosion onto the license plate, but these aftermarket screws are stainless steel for exceptional rust and corrosion resistance. You will, however, need a Phillips screwdriver to fasten the screws.
Honda cars and trucks are known to use steel plate screws. Most Honda license plates can be installed with screws that range in diameter from 1/4 inch to 3/4 inch. Honda license plate screws have a universal fit and don’t need nylon inserts when mounting. So, you can use them on cars, trucks, as well as motorcycles.
You don’t have to worry about corrosion because these screws are usually stainless steel. They hold firmly once installed, thanks to the pan head style. You will require a Phillips head screwdriver to effectively install these fasteners without damaging the drive system.
The standard size for the aftermarket RAM license plate screws is 1/4-14-3/4 with a hex head style and an external hex slotted drive system. These screws are self-tapping, making installation much easier and faster compared to normal screws.
The external hex slotted head allows for simple normal screwdriver installation. They are commonly made of stainless steel for long-lasting durability. They are compatible with most RAM vehicles that feature nylon or plastic screw retainers.
The coated screws, however, may scratch during installation. But you can avoid scratching them with the help of paper towels.
How to Remove Rusted License Plate Screws
Old and rusted license plate screws tend to refuse to come out with the regular or Phillips screwdriver most of the time. This can be quite stressful, especially if it is your first time attempting this do-it-yourself project.
The first and most obvious thing to do would be to use a rust penetrant. A rust penetrant is a low-odor formula that penetrates the threads to loosen the rust to free the screw.
This formula also introduces a protective layer into the threads to prevent the re-formation of rust and corrosion. But in some cases, the rust penetrant may fail to release the rusted screws.
You might think of using an impact wrench, right? But that is a mistake you should avoid by all means. This is so because the impact wrench may force the nut (the one thing holding the license plate screw in place) inside to come loose.
The only remaining solution for a do-it-yourself project would be to use locking pliers or a vice grip. Start by applying some rust penetrant and give it time to sink into the threads all the way to the nut. Then hold the head of the screw with the locking pliers (make sure you have a reliable grip) and slowly turn the screw until it comes out.
Some head styles, however, may be difficult to hold with pliers. So, you can enlarge the holes on the old license plate, pull it out, leaving the screws attached to the vehicle’s body. Then you will be left with enough room to position your locking pliers for a stronger grip.
How to Fix Damaged Threads
People usually mess up the threads by using the wrong type and size of fasteners. Some vehicles accept screws (such as the self-tapping type), while others accept bolts.
Your license plate screws will not hold if the threads are damaged. You need a threaded insert to repair stripped threads.
Start by cleaning the remaining threads, which you can easily do with penetrating oil, compressed air, or a clean rag. Then assemble the thread insert and the installation tool. The thread insert must have the correct pitch, say M6 x 1. Then just run the thread insert in to clean up the threads.
What are self-tapping screws?
Self-tapping screws form or cut a mating thread in a material. Nuts are not necessary when using self-tapping screws. No clearance is also needed since the mating thread fits the screw threads. These screws are popular because of their excellent holding force.
Are license plate screw sizes universal?
No, they aren’t because different brands have varying license plate screw sizes for their vehicles. If you select a bigger size, you may end up damaging the threads and the screws may not install properly. It is always recommended to check with your vehicle’s manufacturer before buying.
As you have seen, each vehicle brand has its specific size for license plate screws except for a few that use the same size. The information provided in this guide should help you pick the right size from the market. But shopping for aftermarket screws could be much easier for you if you get them from an auto shop online because they will use your vehicle make and model to recommend the ideal size.