How to do hidden screws in wood?

Using hidden screws in woodworking projects can provide a clean, seamless look that highlights the beauty of the wood itself. While exposed screw heads can detract from a piece’s aesthetic, hidden screws allow the wood’s grain patterns and colors to take center stage. Whether you are building furniture, installing cabinetry, or completing another wood project, learning techniques for hidden screws can expand your woodworking skills.

Why Use Hidden Screws?

Here are some of the main benefits of using hidden screws in woodworking projects:

• They provide a smooth, flush surface that showcases the wood’s beauty.
• The seamless look creates a more high-end, refined appearance.
• Hidden screws are versatile and can be used in furniture, cabinetry, trimwork, and many other applications.
• They allow you to assemble projects cleanly without exposed fasteners marring the look.
• Hidden screws are secure and allow for sturdy joinery in wood projects.
• They can make staining and finishing simpler by eliminating recessed holes that have to be filled.

In many pieces of furniture and woodworking, visible screws will detract from the natural elegance of the wood grain. The smooth, seamless nature of hidden fasteners allows the wood’s patterns and colors to take the spotlight for a more integrated look.

Types of Hidden Screws

There are several options when it comes to selecting hidden screws for your woodworking projects:

Pocket Hole Screws

Pocket holes involve drilling a small angled hole into one piece of wood that you then drive a screw into from the adjoining piece to make a 90 degree angle joint. Pocket hole screw kits come with a stepped drill bit, screws, and a pocket hole jig to allow for easy drilling and alignment. They provide a strong hidden fastener option for building frames, attaching faceframes to cabinet boxes, assembling furniture, and other right angle joints.

Threaded Inserts

Threaded inserts are small cylindrical pieces of brass or steel that you install in pre-drilled holes. They have internal threads that allow machine screws to then be used to fasten two pieces of wood together. Threaded inserts provide a durable hidden fastener option and allow for repeated assembly and disassembly.

Figure Eight Fasteners

Figure eight fasteners, sometimes called keyhole fasteners, utilize a connector that gets embedded into one piece of wood. The adjoining piece then gets a slot routed into its edge that the connector slips into. Figure eights allow for no-glue, mechanical joints and are commonly used for knockdown furniture that can be disassembled.

Biscuits

Biscuits are small football-shaped pieces of compressed wood that slot into tight fitting grooves in two adjoining boards that are being joined. Glue is applied to the biscuits, which helps align the joint and adds strength. Biscuits provide an invisible joinery technique for edge-to-edge joints.

Floating Tenons

A floating tenon is a removable wooden connector that gets inserted into slots cut into two pieces of stock that are being joined. The tenon gets glued into place, creating an invisible joint. Floating tenons are highly versatile and great for joinery on cabinetry, furniture, trim, and more.

How to Install Hidden Screws

Here is an overview of how to utilize some of the most common hidden screw options:

Pocket Holes

Installing pocket hole joinery involves just a few simple steps:

1. Use a pocket hole jig kit to drill angled holes into one piece of stock at the joint location.
2. Apply wood glue to the joint.
3. Drive pocket hole screws through the pre-drilled holes, screwing them into the adjoining piece of wood.
4. Allow the glue to dry fully before removing the screws or clamps.

Be sure your pocket holes are drilled at the same angles as your screws (usually 15 degrees). Test on scrap pieces first to check fit and finish.

Threaded Inserts

1. Drill a hole slightly smaller than your inserts using a drill press for straight accuracy.
2. Use a tap and mallet to thread the holes so the inserts achieve a snug fit.
3. Drive the inserts into the holes using an insert installation tool.
4. When ready to assemble, use machine screws in the threaded inserts to fasten the adjoining piece.

Take care not to drill holes the entire depth of your stock to avoid breaking through. Only drive inserts flush, not recessed into holes.

Figure Eight Fasteners

1. Drill corresponding holes into the backside of one piece of stock for the connector parts.
2. Use a router to cut corresponding slots into the edge of the mating piece.
3. Glue connectors into one piece, then slide the slotted edge piece onto the exposed connector for a tight fit.

Ensure your connector and slot are orientated correctly before gluing and assembling. Dry fit pieces first.

Biscuits

1. Cut corresponding slots into both joining boards with a biscuit joiner power tool.
2. Apply glue within slots and on biscuit pieces.
3. Insert biscuits into slots, clamp, and allow to dry.

Cleaning any excess glue squeeze-out immediately after clamping helps maintain a hidden look. Allow sufficient depth for entire biscuit to be inserted.

Floating Tenons

1. Use a straight router bit to cut mortise slots into each piece to be joined.
2. Cut a tenon to fit snugly into the slots.
3. Glue tenon into one slot, then fit the mating piece onto the protruding tenon.

Ensure your tenon length matches the combined depth of the two mortises to create a flush edge. Avoid excess glue squeeze-out.

Tips for Hidden Screws

Follow these tips for getting the best results from hidden screw joinery:

• Use scrap wood to test fit joints and make adjustments before assembling your final project.
• Clamp joints tightly until glue sets fully to avoid gaps from appearing once dried.
• Be precise with hole drilling, slot cutting, and joint sizing for a tight seamless fit.
• Only apply as much glue as needed. Excess squeeze-out is difficult to remove from hidden joints.
• Let adhesive cure fully before removing clamps or putting stress on joints.
• Use a drill guide block or jig for pocket holes to ensure consistent angled holes.
• Select moisture-resistant adhesives if the finished piece will be exposed to water.
• Consider appearance and wood movement when orienting the direction of your hidden fasteners.

Advantages of Hidden Screws

Some of the benefits of utilizing hidden screws or fasteners include:

• Enhanced appearance – No visible metal hardware interrupting the natural look of the wood.
• Versatility – Many options work for a wide range of projects and joint locations.
• Strength – They offer sturdy, secure joinery comparable to standard screws.
• Efficient installation – Many hidden screw types can be installed quickly with minimal tools.
• Discreet repairs – Individual fasteners can be easily accessed later if needed.
• Professional results – Hidden screws elevate the fit and finish of DIY projects.
• Longevity – Durable materials like steel threaded inserts hold up well over time.

The main downside is the extra time, tools, and precision required compared to standard visible screw methods. But for many furnishings and woodworking applications, the refined appearance is worth the effort.

Disadvantages of Hidden Screws

There are also some potential disadvantages to consider with hidden screw joinery, including:

• More complex installation – Specialized jigs, router bits, drill guides needed.
• Increased installation time – Achieving tight seamless joints takes precision and care.
• Not suitable for all joints – Limitations based on orientation, wood movement.
• Permanent – Can’t easily disassemble like standard screws.
• Difficult repairs – Accessing damaged hidden fasteners may require disassembly.
• Higher cost – Specialized hardware, tools, and bits add expense.
• Reduced structural strength – Depends on adhesive rather than screws/bolts.

The pros typically outweigh the cons for furniture and cabinetry. But for structural work or applications needing frequent access, standard visible screws may make better sense.

Best Uses for Hidden Screws

Here are some of the best applications for taking advantage of hidden screw joinery:

• Furniture – Tabletops, legs, aprons, rails, and framing.
• Cabinetry – Frames, doors, drawer fronts, face frames.
• Trimwork – Window, door, ceiling, and baseboard trim moldings.
• Paneling – Wainscoting, walls, ceiling, and shower surrounds.
• Shelving – Floating shelves, bookcases, display units.

The key is utilizing hidden fasteners where the orientation allows for concealed joinery. Allow space for drilling, cutting, and fitting – difficult in narrow pieces. Use extra care when joining stained/finished wood to avoid damaging visible surfaces.

Best Joints for Hidden Screws

Certain woodworking joints lend themselves particularly well to hidden screws:

• Pocket holes – Ideal for 90 degree joints like framing and attaching face frames.
• Edge joints – Biscuits or floating tenons work for long seamless edges.
• Miter joints – Great for trim, picture frames, and decorative finishes.
• T-joints – Where a horizontal piece meets a vertical, such as shelving.
• Corner joints – Attach table legs or cabinet corners discreetly.

Consider wood movement and the stresses a joint will encounter. Allow room for drilling and cutting at each joining location without breaking through visible surfaces.

Choosing Hidden Fasteners

Factors to consider when selecting hidden fastener options include:

• Wood type – Strength, hardness, and drilling/cutting properties.
• Joint orientation – Which hidden options work for the direction and angle.
• Disassembly – If the joint needs to come apart later.
• Environment – Screw coating if exposed to moisture.
• Appearance – Fine furniture may dictate more elegant options.
• Skill level – Opt for simpler methods like biscuits for beginners.

Aesthetic, strength, and ease of the installation process all impact the best choice. Test different methods on scrap pieces when possible.

Common Mistakes

Watch out for these common pitfalls when using hidden screw techniques:

• Drilling shallow pilot holes that don’t provide sufficient depth.
• Forgetting to orient biscuits, connectors, figures eights before installation.
• Applying too much glue causing difficult cleanup and potential staining.
• Not fully seating inserts or floating tenons into their holes or slots.
• Rushing the process and ending up with gaps or misaligned joints.
• Clamping too tightly and compressing wood around openings.
• Not allowing enough space for drilling holes and cutting slots.

Avoid these mistakes by taking your time, doing test runs on scrap wood, following hardware dimensions, and allowing glue to cure fully before removing clamps.

Safety Tips

Observe these safety precautions when working with hidden screw techniques:

• Wear safety glasses to protect from flying chips and sawdust.
• Use a dust mask or respirator when cutting, routing, or sanding.
• Unplug power tools before making any adjustments.
• Secure workpieces with clamps to prevent movement while cutting.
• Keep hands away from cutting edges and drill bits.
• Double check drill and cut depths to avoid breaking through visible surfaces.
• Be aware of binding risk when drilling deep narrow holes.

Working slowly and deliberately is crucial for both safety and getting precise seamless results. Ensure bits and cutters are sharp and clean for smoother operation.

Conclusion

Hidden screws allow for beautiful wood joinery without visible metal hardware interrupting sleek designs. While using them requires precision and patience, the impact on the final product’s appearance makes it a valuable technique. Just be sure to educate yourself on the different options and test them out on scrap wood first.

Mastering the use of pocket holes, biscuits, floating tenons, threaded inserts, and figure eights expands your woodworking repertoire. Combined with flawless finishing and staining, hidden screws can help even beginner DIYers achieve professional, seamless results. Just take your time, clamp properly, and allow joints to cure fully before admiring your handiwork.