How to Change Sofa Legs: M8, M10 & 5/16 Hanger Bolt Guide
Changing your sofa legs is one of the easiest and most affordable ways to give existing furniture a completely new look. A simple switch from basic factory legs to solid wood furniture legs can make an IKEA sofa, vintage chair, ottoman, bench, or other upholstered piece feel much more custom.
But before ordering replacement sofa legs, there is one important question:
How are your existing legs attached?
The answer determines whether replacing your legs takes a few minutes or requires adding new mounting hardware.
1. First, Check for Existing Threaded Inserts
Turn your sofa or chair over and remove one of the existing legs.
Look underneath the furniture where the leg was attached. If you see a metal threaded hole built into the furniture frame, you probably already have a threaded insert.
This is the easiest situation.
Your replacement wooden leg simply needs a compatible hanger bolt.
The most common sizes we work with are:
M8 hanger bolt
M10 hanger bolt
5/16" hanger bolt
The bolt size must match the threaded insert already installed in your furniture.
Not Sure What Thread Size You Have?
There is a very easy way to find out.
Remove one of your existing furniture legs and take it to a local hardware store. They can usually identify the thread size of the hanger bolt within a few minutes.
Once you know whether your furniture uses M8, M10, 5/16", or another size, let us know when ordering your replacement legs.
2. What's the Difference Between M8, M10 and 5/16 Hanger Bolts?
These numbers refer primarily to the diameter and thread standard of the bolt.
M8 Hanger Bolts
M8 is an 8 mm metric thread.
It is one of the most common sizes used on modern furniture, particularly European-designed and mass-produced furniture.
Many IKEA furniture designs use metric hardware, and M8 is commonly encountered on replaceable furniture legs. However, don't assume every IKEA product uses M8. Always check the product manual or the existing hardware before ordering.
If you can find the assembly manual for your particular IKEA model, check the hardware specifications. If the bolt or thread size is identified there, send us that information.
M10 Hanger Bolts
M10 is a larger 10 mm metric thread.
M10 hanger bolts are commonly used when a larger and more substantial connection is desired. If your existing threaded insert is M10, your new furniture leg should be fitted with a compatible M10 hanger bolt.
An M10 bolt will not fit an M8 insert, so identifying the existing thread correctly is important.
5/16" Hanger Bolts
5/16" is an imperial thread size, rather than metric.
It is commonly encountered on furniture and hardware made for the North American market.
Although 5/16" and M8 are relatively close in diameter, they are not automatically interchangeable. Their thread specifications can differ.
Never force a bolt into an existing insert simply because it appears to be approximately the correct diameter.
3. Replacing Legs on IKEA and Other Mass-Produced Furniture
We have many customers who purchase affordable, mass-produced furniture and then upgrade its appearance by replacing the original legs.
This can be a much less expensive way to create a more distinctive piece of furniture.
For example, a simple sofa with short factory-made legs can take on an entirely different character with:
Solid walnut legs
White oak legs
Turned wooden legs
Tapered mid-century legs
Ball legs
Bun feet
Taller wooden legs
You keep the furniture you already own while changing one of the details that has a surprisingly large effect on its overall appearance.
For IKEA furniture in particular, first remove an existing leg or check the original assembly manual. If you can determine the mounting specification from the manual, simply send us the information.
4. What If My Sofa Doesn't Have Threaded Inserts?
This is also common, especially with older furniture, custom-built furniture and vintage pieces.
You still have several options.
Option A: Install New Threaded Inserts
This method works particularly well for furniture restoration projects and for experienced DIY customers, furniture makers and professional refurbishers.
A threaded insert is installed into the wooden furniture frame. The corresponding hanger bolt on the furniture leg then screws into that insert.
The basic system looks like this:
Furniture frame → Threaded insert → Hanger bolt → Wooden leg
For suitable projects, we can provide compatible hardware and help you determine the appropriate threaded inserts and installation tools.
Installation normally requires accurately drilling the furniture frame before installing the insert.
Because the strength of the connection depends on the construction and condition of the furniture frame, this method is best suited to customers who are comfortable working with furniture or who have a carpenter or handyman available.
5. An Easier Option: Metal Mounting Plates
If your furniture doesn't already have threaded inserts and you don't want to install them directly into the frame, a metal mounting plate can often provide an easier solution.
The mounting plate is attached to the underside of the furniture using screws.
The furniture leg then connects to the threaded center of the plate using its hanger bolt.
The system is essentially:
Sofa frame → Mounting plate → Hanger bolt → Wooden leg
The mounting plate distributes the attachment across several screws rather than requiring an existing threaded insert in the furniture.
This can make replacement legs possible on many pieces that were not originally designed for screw-in aftermarket legs.
6. Which Installation Method Should You Choose?
The easiest approach is to work with the mounting system your furniture already has.
Existing threaded insert:
Identify its thread size and order the new legs with the matching hanger bolts.
No insert, but you are experienced with furniture restoration:
Installing threaded inserts can create a clean, integrated mounting system.
No insert and you want a simpler installation:
A metal mounting plate may be the more practical solution.
Vintage furniture deserves additional consideration. Older frames can vary significantly in construction and condition, so always make sure the area receiving the new hardware is structurally sound before installation.
7. What to Send Us Before Ordering Replacement Sofa Legs
If you're unsure which mounting option you need, send us:
A photo of the underside of your sofa where the existing leg attaches.
A photo of one removed existing leg and its bolt or mounting hardware.
The thread size, if you already know it.
Your desired leg height and style.
Your preferred wood species and finish.
If you're able to identify the existing thread at a hardware store, even better. Tell us whether it is M8, M10, 5/16", or another specification, and we can prepare the furniture legs accordingly.
A Small Change That Can Transform Your Furniture
Replacing furniture legs is a relatively small modification, but visually it can completely change a sofa, chair, bench or ottoman.
Instead of replacing an entire piece of furniture, you can keep the frame you already like and upgrade its proportions, material and character with handcrafted wooden legs.
Whether you're updating an IKEA sofa, customizing a new piece of furniture or restoring a vintage find, the key is simply choosing the correct mounting system.
Check the existing connection first, identify your hardware, and then choose the wooden legs that give your furniture the look you want.