Selecting the right size nails is a key factor when assembling ready-to-assemble (RTA) cabinets. Using nails that are too small can result in a weak connection and cabinets that are unstable. On the other hand, nails that are too large can split the wood. This article will provide a definitive guide on what size nails work best for RTA cabinets.

An Introduction to Nail Sizes

Nails are available in a wide range of diameters, lengths, and types. Nail diameter is measured in “penny” units. The larger the penny size, the thicker the diameter of the nail. Some common nail sizes include:

  • 2d (2 penny) – 1 inch long, 0.080 inch diameter
  • 3d (3 penny) – 1.25 inches long, 0.090 inch diameter
  • 4d (4 penny) – 1.5 inches long, 0.100 inch diameter
  • 6d (6 penny) – 2 inches long, 0.113 inch diameter
  • 8d (8 penny) – 2.5 inches long, 0.131 inch diameter
  • 10d (10 penny) – 3 inches long, 0.148 inch diameter
  • 16d (16 penny) – 3.5 inches long, 0.162 inch diameter

As you can see, as the penny size increases, so does the nail diameter and length.

What Size Nails are Best for Assembling RTA Cabinets?

For most RTA cabinet assemblies, 6d finishing nails are recommended. Here’s why:

  • 6d nails are thick enough to provide a solid wood connection – The 0.113 inch diameter shank is thick enough to hold the cabinet components together firmly without splitting the wood. Thinner nails may not provide enough holding strength.
  • 6d nails are short enough to avoid poking through cabinet walls – The 2 inch length is sufficient to penetrate through cabinet face frames and into shelves/sides without protruding all the way through. Longer nails like 8d and 10d may poke through the cabinet interior.
  • 6d finishing nails have small heads – Unlike common nails, finishing nails like 6d have very small heads that can be easily countersunk and concealed with wood filler. This results in an invisible nail fastening.
  • 6d nails are designed for assembling furniture – Finishing nails are made specifically for fastening furniture components together. The small head and fine shank result in minimal wood damage during assembly.

In summary, 6d finishing nails strike the ideal balance of thickness, length, and design features that make them well-suited for assembling RTA cabinets. Let’s look at some more reasons why they are the top choice.

Benefits of Using 6d Finishing Nails for RTA Cabinets

Here are some of the key advantages of using 6d finishing nails during RTA cabinet assembly:

1. Provides a Sturdy Wood Connection

The 0.113 inch diameter shank of a 6d nail provides a robust fastening between wooden cabinet components like face frames, sides, shelves, and doors. The thicker shank means greater holding power while minimizing the risk of the nails pulling loose over time. This results in rigid, wobble-free cabinetry.

2. Ideal Fastener Length

At 2 inches long, 6d nails are able to penetrate deep enough into cabinet frames and sides to hold everything together firmly. However, they are short enough to avoid protruding completely through 3/4 inch cabinet walls and being visible inside cabinets.

3. Allows for Concealed Nailing

6d finishing nails have very small, tapered heads that can be easily countersunk into the wood using a nail set tool. The holes can then be filled with wood putty for an invisible nailing appearance. No visible nails means a more polished, furniture-like look.

4. Minimal Risk of Wood Splitting

Larger diameter nails like 8d or 10d have a higher risk of splitting more delicate woods like particle board during nailing. The thinner 0.113 inch shank of 6d nails is less likely to split panels, allowing for easier nailing and cleaner results.

5. Quick and Easy Hammering

The short length and thinner diameter of 6d nails allows them to be quickly hammered in using only light taps, without bending. This enables efficient assembly of multiple cabinets. Longer, thicker nails require more forceful hammering which can slow things down.

6. Provides Good Value

Boxes of 6d finishing nails are very economical compared to other specialty nails. You can buy enough 6d nails to assemble multiple cabinets for just a few dollars. Using more expensive or proprietary cabinet nails is not necessary.

As you can see, 6d finishing nails have many advantages that make them the ideal fastener for RTA cabinet projects. Next, let’s look at some recommended tips when using them.

Best Practices When Using 6d Finishing Nails for Cabinets

Follow these guidelines to get the best results when nailing RTA cabinets together with 6d finishing nails:

  • Use nail holes – Take advantage of any pre-drilled nail holes in the cabinet components. This ensures proper alignment and prevents wood splitting.
  • Countersink nails – Make sure to countersink the small nail heads about 1/8 inch into the wood using a nail set. This allows concealing with filler.
  • Aim nails diagonally – Aim nails diagonally through face frame edges into side panels and shelving for maximum holding power. Avoid straight in-and-out nailing.
  • Nail from inside cabinets – For more concealed nailing, you can nail through the inside of the cabinet to hide nail holes.
  • Nail every 4 inches – Use 6d nails spaced every 4 inches along cabinet face frames and sides to evenly fasten components.
  • Double up on nail holes – For extra holding strength, consider driving two 6d nails into every pre-drilled nail hole in the cabinet.
  • Apply wood glue – Coating joints with wood glue before nailing adds even more strength and durability to the assembly.
  • Fill holes – Use wood filler to conceal all nail holes for a seamless finish. Sand and stain for an invisible nailing appearance.

Following these best practices when nailing your cabinets together with 6d finishing nails will result in super-strong assemblies that look professionally finished.

Alternatives to 6d Finishing Nails

While 6d finishing nails are recommended for most RTA cabinet projects, here are some other size nail options along with pros and cons of each:

4d Finishing Nails

  • Pros – Thinner shank poses even less risk of wood splitting. Easier to hammer in and countersink. Good for delicate materials.
  • Cons – Lack of nail holding strength. Higher risk of loosening over time. Not ideal for heavy cabinet components.

8d Finish Nails

  • Pros – Longer reach provides very sturdy wood connections. May be needed for thicker cabinet materials.
  • Cons – Increased chance of nails poking through side walls. Harder to hammer and countersink neatly.

18 Gauge Brad Nails

  • Pros – Very narrow shank leaves smallest nail holes. Easier nailing of delicate wood.
  • Cons – Very poor holding strength. Higher cost than regular finishing nails.

Small Screws

  • Pros – Provide extremely rigid cabinet joints. Allow for easy disassembly.
  • Cons – Require pre-drilling holes. More time consuming to install than nails.

As you can see, each of these alternatives has disadvantages compared to 6d finishing nails for typical RTA cabinet assembly. However, they may be suitable alternatives depending on specific cabinet materials and assembly requirements.

Answering Some Frequently Asked Questions

Here are answers to some common questions people have about using nails to assemble RTA cabinets:

Are 6d finishing nails long enough to assemble cabinets?

Yes, at 2 inches long, 6d nails provide sufficient fastening between typical 3/4 inch cabinet face frames, sides, and shelves. The nails are able to penetrate deep enough without coming out the other side.

What size nails should be avoided with particle board cabinets?

Avoid large nails like 8d or 10d with particle board. The thicker shanks pose a high risk of splitting the delicate engineered wood. Opt for thinner 6d nails instead.

Is it OK to assemble cabinets with common nails instead of finishing nails?

While possible, common nails have larger heads that cannot be countersunk for a concealed look. Finishing nails are specifically designed for invisible fastening of furniture like cabinets.

How many 6d nails should be used to attach a cabinet door?

A good rule of thumb is to use 6-8 6d finishing nails spaced evenly around a cabinet door to provide a secure attachment to the face frame.

What nail length is needed for assembling 2×4 cabinets?

With a thicker 2×4 cabinet construction, an 8d finishing nail that is 2.5 inches long may be better suited than a 6d nail. The longer length provides more holding power.


When assembling RTA cabinets, selecting the proper fasteners is key to obtaining a sturdy finished product. Based on their diameter, length, and design attributes, 6d finishing nails are recommended by experts as the best size nails for constructing most typical RTA cabinets.

Their 0.113 inch shank provides ideal holding strength without risk of wood splitting. The 2 inch length enables concealed fastening deep within cabinet frames and sides. Countersunk 6d finishing nails allow for invisible nailing and professional-looking results. Following best practices when nailing, like pre-drilling holes and applying wood glue, will further enhance the quality and longevity of the finished cabinets.

While nails like 4d, 8d, or screws may work for some specialized applications, 6d finishing nails are generally the most reliable fastener choice for assembling ready-to-assemble cabinets of common wood materials. Investing in a box of quality 6d finishing nails will be money well spent when putting together your next set of RTA cabinets.