How to Attach Table Legs with Bolts: Hanger Bolts vs Threaded Inserts

How to attach table legs with bolts gives you something better: a removable, rock-solid connection that handles heavy weight and stays tight through years of use. You might be building a dining table, fixing up an old coffee table, or trying woodworking for the first time. Either way, bolts give you a much stronger hold than screws alone.

In this guide, Flowyline shows you 2 best methods: hanger bolts and threaded insert nuts + bolts with clear steps that work for beginners and experienced builders alike. Let's see how to attach table legs with bolts that last for years to come!

Table Leg Mounting Hardware: What You'll Need to Buy

Walk into a hardware store and ask for "bolts for table legs," and you'll likely get a confused look. The world of table leg mounting hardware has its own vocabulary, so let's break down what pieces you need and why each one matters.

1. Bolts and Threaded Inserts: The Hidden Anchor Point

Threaded inserts are metal cylinders with threads on the outside (to grip the wood) and threads on the inside (to accept your bolt). They're what make the whole system work.

There are 2 main types of threaded Inserts and bolts:

• Screw-in inserts (E-Z Lok style): These have external threads and a hex socket on top. You drill a pilot hole, then use an Allen key to screw them into the wood. They work great in hardwoods and give you the strongest hold.

Attaching table legs with bolts

Credit: Flowyline

Shop now: Threaded Inserts And Bolts | Size M6 and M8 | 20 Sets | Table Leg Hardware

 

• Hammer-in inserts (T-nuts): These have sharp prongs that bite into the wood when you hammer them in. They're faster to install but don't hold as well in softer woods. Flowyline generally recommends the screw-in inserts for furniture that needs to last.
  
  

Hammer-in inserts (T-nuts) are faster to install, but don't hold as well in softer woods

Photo: Freepik

2. Hanger Bolts: The Two-Sided Solution

A table leg hanger bolt looks unusual the first time you see one.

• One end has wood screw threads that grip into your table leg.
• The other end has machine threads that screw into a threaded insert or metal plate.

This dual-thread design lets you create a removable connection between two pieces of wood.

Attaching table legs with hanger bolts

Photo: Flowyline

Standard sizes you'll encounter:

• 1/4"-20 (1/4 inch diameter, 20 threads per inch): Good for legs under 2 inches in diameter
• 5/16"-18: The most common size for typical dining and coffee table legs
• 3/8"-16: What you want for heavy-duty applications and attaching 4x4 legs to table projects

Besides, the length matters too. Most hanger bolts come in 2.5" to 4" lengths. You'll want about 1.5 — 2 inches screwed into your leg, which leaves enough exposed threads to securely engage the insert in your tabletop.

Now that you know what table leg screws and hardware you need, let's get into the actual installation process.

How to Attach Table Legs with Bolts & Threaded Inserts (Heavy-Duty)

If your table legs have a metal mounting plate on top with holes already drilled, bolts & threaded inserts are perfect for you. This is the fastest way to attach table legs with bolts because half the work is already done for you.

Simply install threaded inserts into your tabletop at matching positions, then bolt everything together.

How to attach table legs with bolts to metal

Credit: Flowyline

Shop now: 307 Tulipe 28" Industrial Metal Table Base

Complete Parts to Assemble a Leg to Table

For a typical two-leg dining table with pre-drilled holes, here's what you'll need:

• 2 metal table legs with mounting plates (each plate needs 8 holes & you don't need to use all the holes)
• 16 threaded inserts (8 per leg, sized to match your bolts)
• 16 furniture bolts (matching thread size, length based on your tabletop thickness)
• Drill with brad point bits (sized for your threaded inserts)
• Hex key or Allen wrench (for installing screw-in threaded inserts)
• Measuring tape and carpenter's square
• Pencil for marking your spots
• Wood glue or epoxy (optional, for extra insert security)
• Optional: drill stop collar (helps you drill to the same depth every time)

The exact sizes depend on your specific legs, but most metal furniture legs use either M6 or M8 threaded inserts (which correspond to approximately 1/4" or 5/16" in imperial sizing).

Check your leg's mounting plate holes to confirm before buying hardware for attaching table legs with bolts.

Step 1: Position and Mark Your Leg Locations

1. First, flip your tabletop upside down on a clean, soft surface. Maybe a blanket or foam padding works great to prevent scratches.
2. Measure in from each edge to determine where your legs should sit.
3. For most tables, putting the legs about 2 to 3 inches from the edges gives you good stability without looking odd. Use your measuring tape and carpenter's square to make sure these measurements match on all corners.
4. Take one metal leg and place its mounting plate exactly where you want that leg to sit. The plate should be flat against the tabletop with the leg pointing away (remember, you're working upside down).
5. Grab your pencil and mark the center of each of the 8 mounting holes in the plate. These marks show you where to drill for your threaded inserts. Do this same thing for all leg positions.

Measure and mark the center point of each mounting hole

Photo: YouTube | Blacktail Studio

Step 2: Drill Pilot Holes for Threaded Inserts

This is an important drilling step.

1. Choose the correct drill bit size

Your bit size depends on your specific threaded insert brand and type. ALWAYS check the manufacturer's specifications, as sizes vary significantly between brands.

As a general starting point for screw-in brass inserts in typical hardwoods:

• 1/4"-20 inserts: Start with 23/64" to 25/64" drill bit (test on scrap first)
• 5/16"-18 inserts: Start with 31/64" to 33/64" drill bit (test on scrap first)
• 3/8"-16 inserts: Start with 35/64" to 37/64" drill bit (test on scrap first)

IMPORTANT: Different insert types (E-Z Lok, brass vs. steel, knife thread vs. hex drive) require different hole sizes. The pilot hole should be 1 — 2mm smaller than the insert's outer diameter to allow the threads to grip properly.

2. Set your drilling depth

Threaded inserts should go about 3/4 of their length into the wood, leaving 1/4 sticking out. If your inserts are 1 inch long, drill 3/4 inch deep. A stop collar on your drill bit ensures consistent depth across all 16 holes.

Drill pilot holes using a brad point bit with a stop collar

Photo: Flowyline

3. Use a brad point drill bit

And, if you can, use a brad point bit. The center point keeps the bit from sliding around, so your hole starts exactly where you marked it. This matters when you need to line up the mounting plates later.

Drill straight down into each marked spot. Keep your drill perpendicular to the tabletop. If you drill at an angle, your inserts will sit crooked, and then your mounting plates won't line up right. That's just asking for headaches.

Step 3: Install Threaded Inserts with Threadlocker

Steel threaded inserts work better than brass or zinc ones because they're stronger. It's time to install them:

1. Put a small drop (size of a match head) of wood glue or epoxy on each insert before you screw it in.
2. If you have Allen-style inserts, use a hex key because it gives you better control. The glue stops everything from loosening up over time.
3. Screw each insert into the holes right away. Don't wait for the glue to dry first. Turn clockwise until they sit flush with the wood surface.
4. Repeat this installation process for all 16 inserts.

Install threaded inserts with hex key and threadlocker

Photo: Flowyline

Step 4: Test-Fit Your Metal Legs

In step 4th of how to attach table legs with bolts, you take each leg and set its mounting plate over the 8 threaded inserts you just put in at that corner. The holes in the mounting plate should line up perfectly with your inserts.

• If they don't, something went wrong when you marked or drilled the holes. Don't try to force it because you'll strip the inserts or crack your tabletop.
• If the alignment is just slightly off, like a millimeter or two, you'll need to open up the holes in the metal plate a bit with a file or a larger drill bit. But if it's off by more than that, you should install new inserts in different spots.
• Check all 2-leg positions like this.

Step 5: Attach Table Legs with Bolts Through the Mounting Plates

Next, grab one metal leg and line up its mounting plate with the 8 threaded inserts at one corner. Start one bolt through a hole in the mounting plate and thread it by hand into the insert below it. Don't tighten it yet, just get it started.

Do the same thing with the other bolts. Once all bolts are threaded in and snug by hand, then you can start tightening them down properly.

Thread bolts through mounting plate into the inserts

Photo: Flowyline

Tips for wood movement:

• If your tabletop is solid wood (not plywood or MDF), tighten the bolts snug, then back each one out about 1/8 to 1/4 turn. This slight looseness lets the wood expand and contract seasonally without stressing the connection.
• For plywood or engineered wood tops that don't move much, you can leave them fully tight.

Step 6: Flip and Test Your Table

• With all two legs attached, you carefully flip the table right-side up.
• Press down firmly on each corner of the table.
• Push down on the center of the table with significant force. The connection should feel absolutely solid with no flex or movement at the leg attachment points.
• If you feel any give, re-check your bolt tightness.

Well, if everything checks out, congratulations! You've successfully learned how to attach table legs with bolts that will last for years.

Test the completed table for stability and wobble

Photo: Flowyline

Below, we've included a video that shows how to attach table legs with bolts. Watching it will help you see each step more clearly. And if mounting plates aren't your thing, keep reading because we cover other attachment methods further down.

You might like: How to Attach Legs to a Table Without Apron

How to Attach Table Legs with Hanger Bolts

Attaching table legs with hanger bolts is great for standard dining table dimensions, desks, and coffee tables. It's what furniture makers use when they want strong, removable legs without visible hardware.

The process takes about half an hour for a four-leg table once you have your materials ready.

Step 1: Install Hanger Bolts into Your Table Legs

We start with your table legs. You need to get the hanger bolt centered and straight, or everything else will be misaligned.

1. Mark the center point

• Flip your leg upside down so you're looking at the top where it will attach to the table.
• Use a ruler or combination square to find the exact center and mark it with a pencil.
• For square legs, draw diagonal lines from corner to corner — where they cross is your center.
• To attach the pedestal base or round legs, you can use a center finder tool or simply eyeball it as close as possible.

2. Drill the pilot hole (this is critical):

The pilot hole needs to be slightly smaller than the wood screw portion of your hanger bolt. If it's too big, the threads won't grip. Too small, and you'll split the wood or strip the hanger bolt trying to screw it in.

Hanger Bolt Size	Pilot Hole Size (Softwood)	Pilot Hole Size (Hardwood)	Drill Depth
1/4"-20	7/64" to 1/8"	9/64" to 5/32"	2 — 2.5"
5/16"-18	1/8" to 9/64"	5/32" to 11/64"	2 — 2.5"
3/8"-16	5/32" to 11/64"	3/16" to 13/64"	2.5 — 3"

Drill straight down into your marked center point. Use a piece of tape on your drill bit to mark the depth so you don't drill too deep. You'll need to go about 2 — 3 inches deep (depending on your bolt length).

NOTE: The pilot hole should be approximately 65 — 75% of the wood screw diameter. These sizes work for typical furniture woods. It's advised to test on scrap wood first, as wood density varies significantly.

3. Screw in the hanger bolt

Hanger bolts don't have a head you can grab with a wrench. The traditional method is to thread two nuts onto the machine thread end, tighten them against each other (jam them together), then use a wrench on the lower nut to drive the bolt.

Once it's screwed in as far as you want, back off the nuts and remove them.

A faster trick: if you have locking pliers (Vise-Grips), you can carefully clamp onto the smooth area between the wood threads and machine threads. Just don't clamp so hard, or you'll damage the threads.

Screw the wood thread end into your pilot hole, turning slowly and steadily. You want about 1.5 — 2 inches of the wood threads buried in the leg. Stop when you have roughly 3/4" to 1" of machine threads sticking out. This exposed portion will screw into the threaded insert in your tabletop.

Step 2: Install Threaded Inserts in Your Tabletop

Now flip your tabletop upside down on a clean, flat surface. You'll be working on the underside where no one will see the hardware.

1. Mark your leg positions

Measure in from each edge to determine where your legs should sit. For most tables, the legs are often positioned about 2 — 3 inches in from the edges.

Next, use your measuring tape and a square to mark these positions accurately. If your marks are off, your table will sit crooked. Take your time here — measure twice, drill once.

2. Drill pilot holes for the inserts

Threaded inserts need a larger pilot hole than regular screws because you're making room for both the insert's body and its external threads.

For screw-in inserts, you can follow this guide:

Insert Size	Pilot Hole Size	Drill Depth
1/4"-20	7/16"	1" minimum
5/16"-18	1/2"	1" minimum
3/8"-16	9/16"	1 — 1.25"

The depth matters more than you might think. If your insert doesn't sit deep enough, the hanger bolt won't fully engage, and you'll end up with wobbly legs. Therefore, we aim for at least 1 inch deep, preferably a bit more if your tabletop is thick enough.

3. Install the threaded inserts

Now, you take one insert and place it over your pilot hole. The hex socket should face up so you can reach it with your Allen key. Turn it clockwise slowly and steadily while pushing down as you turn.

• If it feels really hard to turn, your pilot hole is probably too small.
• But if it just spins without catching the wood, then your hole is too big.

When that happens, move over a bit and try a new spot. Or you can fill the hole with wood glue and toothpicks, wait for it to dry, then drill again.

Keep turning until the top of the insert sits level with the wood surface, or just a hair below it. You don't want it sticking up, but don't bury it too deep either. Your hanger bolt needs to reach it properly.

Step 3: Attach Your Legs to the Tabletop

1. Take one leg with its hanger bolt already attached and line up the exposed threads with one of the inserts in your tabletop. Start threading the bolt in by hand, turning the whole leg clockwise.
2. If you feel resistance or the threads won't catch, stop and back it out. Check inside the insert for wood shavings or debris, then try again.
3. Once you can't turn it by hand anymore, give it another quarter to half turn to snug it up. Once it's tight enough so there's no wobble, but don't go crazy with it.
4. Do the same thing for the other three legs. After all four are on, you carefully flip your table right-side up.

Step 4: Test for Stability

Lastly, you press down on each corner of the table. Does it rock at all? If it does, check that all the legs are tightened the same amount. Sometimes one corner sits a bit higher than the others. When that happens, you simply adjust it or add furniture pads underneath to level it out.

Now give the table a good shake. Walk around and lean on different spots to test it. If you did everything right, and your table feels solid with no wobble. It's ready to use.

Why Choose Bolts Over Screws for Table Leg Attachment Methods?

Regular wood screws seem simple enough. You drill a pilot hole, drive the screw in, and you're done. But after that, wood expands and contracts with humidity changes.

Tables get moved. Weight shifts during daily use. Those screws gradually loosen, and when you try to tighten them, the holes strip out. Now, you've got a wobbly table and no easy fix.

Bolts solve this problem in 3 important ways:

1. Removability: Bolt-attached legs unscrew in minutes without damaging anything. You can transport your table flat, then reassemble it wherever you need it. Try that with wood glued joints or permanent screws.
2. Strength: Attaching table legs with bolts means each leg can easily support 300 — 500 pounds, depending on the hardware size you choose. That's strong enough for the heaviest dining tables or workbenches.
3. Longevity: Bolts don't strip out like screws. The threaded inserts stay secure in the wood, and you can remove and reattach the metal table legs dozens of times without weakening the connection. If a bolt ever does wear out, you simply replace it, and then the insert stays put.

You see, they're not necessarily harder to install than screws. Instead, how to attach table legs with bolts requires a slightly different approach and the right hardware.

FAQs

1. What is the Strongest Way to Attach Table Legs?

The strongest way to attach table legs is to implement traditional mortise and tenon joinery with glue. It works like a really precise puzzle where one part fits perfectly into another.

• The leg or apron has a shaped piece sticking out, and that's called a tenon.
• The other piece has a matching rectangular hole cut into it, called a mortise.

You fit the tenon into the mortise, then glue them together. These wooden table leg attachment methods can last for generations. Some people also add wooden pins or wedges to lock everything in place even more permanently.

Mortise and Tenon gives you the strongest possible table with no screws

Photo: Wikimedia Commons

2. How to Use Hanger Bolts for Table Legs?

Table leg hanger bolts have wood threads on one end and machine threads on the other. Here's how to use hanger bolts for table legs:

• First, drill a pilot hole in your leg. Use a 3/16" bit for 1/4" bolts, or a 1/4" bit for 5/16" bolts.
• Then screw in the hanger bolt using the double-nut method.
• Thread two nuts onto the machine end, tighten them against each other, and use a wrench to turn the whole thing. Leave about 3/4" to 1" of machine threads sticking out.
• Next, install matching threaded inserts in your tabletop.
• After that, you just twist the legs in to attach them.

3. How to Attach 4x4 Legs to a Table?

Attaching 4x4 legs to table needs heavier hardware than smaller legs. You should use 3/8"-16 bolts at a minimum. Here is how to attach 4x4 legs to table:

• Start by drilling a centered pilot hole in each leg. Make it 5/32" to 11/64" wide for softwood or 3/16" to 13/64" for hardwood, and about 2.5 to 3 inches deep. Then install your hanger bolts, leaving 1 inch of threads sticking out.
• For your tabletop, drill pilot holes according to your specific threaded insert manufacturer's recommendations
• Install matching threaded inserts in these holes.
• Thread the legs into the inserts until they're snug, then back them off about 1/8 of a turn. This gives the wood a bit of room to expand and contract naturally.
• If your tabletop is thin, you'll want to use mounting blocks or corner brackets for extra support. When you install 3/8" hardware properly, it can support around 300 to 500 pounds per leg.

How to Attach Table Legs with Bolts: Conclusion

Instead of hanger bolts, some builders or even we prefer using threaded inserts in both the tabletop AND the legs, then connecting them with a standard bolt or mounting block. It works really amazingly for heavy tables or very thick tops where you need longer threaded engagement.

The advantage here is adjustability. If your table ends up slightly uneven, you can add washers or adjust the bolt depth to level everything out. With hanger bolts, what you install is what you get.

As you can see, learning how to attach table legs with bolts isn't complicated once you understand the hardware and follow the steps carefully. And, if you have any questions, please feel free to ask us anytime, and check our new blogs. Thank you for reading!