M6, 1/4 In., No.14: Plate Cover Mounting Hardware Checklist (U.S.)

For most license plate covers, stainless steel machine screws with nylon caps or stainless sheet-metal screws paired with nylon washers give the best mix of grip and corrosion resistance. Lightweight plastic covers do fine with a nylon screw-and-cap kit instead. You’ll typically match one of three sizes, M6, 1/4 inch, or No.14, and before you buy, check your state’s rules on covers that obscure a plate.

TL;DR:

• Stainless steel screws with nylon caps or stainless sheet-metal screws with nylon washers offer the best corrosion resistance and grip for most license plate covers.
• Most mounting kits are compatible with existing holes and do not require drilling, except for some bracket kits that need removal of tow-hook caps.
• Proper installation involves hand-tightening screws, using nylon washers to avoid cracking, and confirming all characters and stickers stay fully visible.
• States increasingly restrict covers that obscure or distort license plate characters or validation stickers, making legal visibility checks essential before installation.

Table of Contents

• Shortlist of mounting hardware kits and how they differ
• What materials and screw sizes mean for fit and longevity
• Step-by-step installation and practical tips to avoid damage
• Legal visibility rules and safety checks for plate covers
• Buying checklist: quick selection criteria when shopping online or in-store
• Publisher perspective: practical trade-offs and recommended approach
• Alternative option: the client’s plate-cover product with tool-free mounting
• Sources
• FAQ

Shortlist of mounting hardware kits and how they differ

Shoppers run into four kit types repeatedly, and each solves a different mounting problem.

• Stainless screw and cap kits: metal screws with snap-on caps that hide the head, a solid pick for both metal and plastic covers.
• Nylon or black plastic kits, like the Auto Drive 8-piece black nylon license plate fastener kit: rustproof screws and caps built for cosmetic, non-structural mounting on lightweight covers.
• Tow-hook bracket kits: a bracket that mounts to the tow-hook point, letting you skip bumper holes entirely.
• Security fastener kits: tamper-resistant heads that need a special driver, aimed at theft deterrence rather than corrosion.

Most of these use existing plate or bumper holes and need no drilling, with the exception of some bracket kits that require you to remove a tow-hook cap first. All four are compatible with mechanical and electric plate covers, since the cover mounts over the existing plate rather than replacing the fastening points.

What materials and screw sizes mean for fit and longevity

Screw sizing trips up a lot of first-time buyers. M6 is a metric thread about 6 millimeters across, 1/4 inch is its closest imperial cousin, and No.14 refers to a sheet-metal screw gauge common on older brackets. Measure your existing hole diameter before ordering, since a screw that’s even slightly oversized can crack a plastic cover.

• 304 stainless handles road salt and rain well and suits most climates.
• 316 stainless adds molybdenum for better resistance in coastal or heavily salted regions.
• Zinc-plated steel costs less but can show surface rust within a couple of seasons in wet climates.
• Nylon never rusts but isn’t meant for structural loads, so it fits cosmetic covers, not heavy brackets.

Many states now restrict or ban covers that obscure a plate’s characters or validation stickers, and enforcement has tightened as of 2025, according to the New York DMV’s consumer alert. That makes hardware choice only half the job: a pan head screw sits low and resists snagging, while a countersunk screw needs a matching bevel or it will crack a thin plastic cover when tightened.

Step-by-step installation and practical tips to avoid damage

Gather a screwdriver or low-torque driver, nylon washers, and a small amount of threadlocker before you start. A torque driver isn’t required, but it helps you stop before the screw bites into the cover.

1. Remove the old plate or cover and check the hole spacing against your new fasteners.
2. Slide a nylon washer onto each screw to spread the load and prevent point pressure.
3. Insert screws through the plate or cover into the mounting holes.
4. Hand-tighten each screw until snug, then add a quarter turn at most.
5. Snap on caps if included, and confirm nothing rattles when you tap the plate.

For a tow-hook bracket install, remove the tow-hook access cover, thread the bracket’s bolts into the factory-tapped hole, torque them to the bracket manufacturer’s spec, then mount the plate to the bracket using the same washer approach.

Pro Tip: Hand-tighten first and stop as soon as the plate stops moving; over-torquing plastic covers is the most common cause of hairline cracks, and a drop of threadlocker on the threads (not the head) keeps screws from backing out over rough roads.

Once installed, check that every character and any validation sticker remains fully visible, since a crooked cover can block a corner even with perfect hardware.

Legal visibility rules and safety checks for plate covers

Visibility is the test that matters most. Many states prohibit any cover, shield, or device that obscures, blocks, or distorts a plate’s characters or validation stickers, and penalties vary by state, per the New York DMV. Some jurisdictions enforce this as a secondary offense discovered during another stop, while others allow direct enforcement on sight.

• Check your state DMV’s current rules before installing any cover.
• Confirm all characters and stickers stay legible from a normal viewing distance.
• Remove or adjust the cover if local enforcement treats it as a violation.

Buying checklist: quick selection criteria when shopping online or in-store

Before you check out, run through a short list so you don’t end up with the wrong screw length or a kit missing washers.

• Confirm the screw size (M6, 1/4 inch, or No.14) matches your existing holes.
• Check that included screw lengths suit your plate-plus-cover thickness, not just the plate alone.
• Note the material and coating: nylon for cosmetic covers, stainless for wet or salted climates.
• Verify caps and washers are included, since these prevent scratches and over-tightening.
• Ask about drilling requirements if you’re considering a bracket kit.
• Confirm the seller’s return policy in case sizing is off.

Watch for vague listings that skip screw size or material, and be skeptical of marketing that leans on phrases like “hide your plate” rather than describing the hardware itself. Choose security fasteners over standard kits only if theft deterrence matters more to you than easy removal, since they require a matching driver every time you need access.

Publisher perspective: practical trade-offs and recommended approach

Standard hardware wins on simplicity, but bracket kits earn their keep on vehicles with no front holes, and security fasteners pay off only if theft is a real concern in your area. Some plate covers are built for tool-free mounting, which is where this comparison started.

— GoGhost

Alternative option: the client’s plate-cover product with tool-free mounting

If matching screw sizes and washers sounds like more hassle than you want, the Ghost Curtain Cover mounts without separate fasteners or drilling, using a tool-free install designed for a universal fit on standard plates.

This suits buyers who want one product that handles both covering and mounting, rather than sourcing a fastener kit separately. It’s a mechanical alternative to GoGhost’s electric option, priced as listed on the Ghost Curtain Cover product page.

FAQ

What size screws do license plates typically use?

License plates commonly use M6 or 1/4 inch screws, and you should measure your existing hole diameter before ordering. Retail pages and packaging are the best place to confirm exact compatibility for your kit.

Is stainless steel or nylon better for plate cover hardware?

Stainless steel resists corrosion better and suits metal covers or salted, wet climates, while nylon never rusts but works best on lightweight plastic covers rather than structural loads. Choose based on your climate and the cover’s material.

Are license plate covers legal to install?

Many states prohibit any cover that obscures a plate’s characters or validation stickers, and penalties vary by state, according to the New York DMV. Check your state’s current DMV guidance before installing any cover.

Do tow-hook bracket kits require drilling?

Most tow-hook bracket kits use the vehicle’s existing tow-hook mounting point, so no drilling into the bumper is needed. You typically remove a tow-hook access cap first, then bolt the bracket into the factory-tapped hole.

What tools do I need to install plate cover mounting hardware?

A basic screwdriver or low-torque driver handles most kits, and nylon washers help prevent over-tightening into plastic covers. A torque driver and a small amount of threadlocker are optional but useful for a snug, rattle-free fit.