How to Measure Bed Leg Thread Size and Find the Right Replacement Legs in New Zealand

If you're replacing bed legs, castors, or glides on a bed base, the most important thing to know is the thread size used by your bed manufacturer. Ordering the wrong thread size can result in legs that won't fit your bed, causing sleepless nights on a leg-less bed, and costly, unnecessary returns.

Fortunately, identifying the correct bed leg thread size is usually straightforward. In this guide, we'll explain how to measure your existing bed legs, identify common thread sizes, and provide a reference chart for popular New Zealand bed manufacturers.

Why Bed Leg Thread Size Matters

Most replacement bed legs screw into a threaded insert fitted to the base of the bed. While many New Zealand manufacturers use common thread sizes, there is no universal standard.

The most common thread types found on New Zealand beds include:

• M8 Metric Thread
• 5/16 Inch Imperial Thread
• 3/8 Inch Imperial Thread
• Push-In Pin Fittings

Before purchasing replacement bed legs, castors, or glides, it's important to confirm which fitting your bed requires. The following is Caford Castor’s quick reference guide to identifying your bed leg thread size…

How to Measure Your Bed Leg Thread Size

Method 1: Use a thread gauge

The most reliable way to identify your bed leg thread size is to remove one leg and use a thread gauge, or test different nuts until one screws on smoothly by hand. Check carefully and never force it; if it jams after a turn or two, the size or pitch is wrong and forcing it may damage the thread.

Method 2: Send us your bed leg

Drop by our warehouse or send one of your current bed legs to us HERE, and we can quickly identify the thread size by testing it against sample nuts to find the perfect match. If you have couriered your leg to us, we will then return your bed leg with your order.

Method 3: Contact the Manufacturer

If you're unsure of your bed’s brand, check your mattress and bed base for the make and model. If you contact the manufacturer directly, they may be able to confirm which fitting is used with your model.

Here are the Common Bed Leg Thread Sizes Used by New Zealand Manufacturers

The following guide covers some of New Zealand's most recognised bed manufacturers.

Warning:  Manufacturers may occasionally change fittings between models and production years. Always verify your existing fitting before purchasing replacement bed legs or castors.

What Size Thread Are Sleepyhead Bed Legs?

Sleepyhead beds commonly use either a push-in pin fitting or an M8 threaded fitting, depending on the model and age of the bed base. Because Sleepyhead has used multiple attachment systems for various purposes, it is always recommended to remove one of the existing legs and check the fitting before ordering replacements.

If your Sleepyhead bed uses a threaded leg, M8 is the most common size. However, some models use push-in pin legs that cannot be replaced with standard threaded legs without an adaptor. You can learn more about replacing your bed legs when the attachment fitting doesn’t match in our guide here.

What Size Thread Are Waikato Beds Bed Legs?

Waikato Beds typically use M8 threaded bed legs. This is one of the most common thread sizes used in New Zealand, making it relatively straightforward to source replacement bed legs, castors, glides, and bed risers.

Before purchasing replacements, it is still recommended to compare the new fitting against an existing leg to ensure compatibility.

What Size Thread Are Wellington Beds Bed Legs?

Wellington Beds commonly use a 5/16-inch imperial thread for bed legs and castors.

A common mistake is to assume that a 5/16-inch thread is the same as an M8 thread. While the diameters are similar, the thread pitch is different, and the two are not interchangeable. Installing the wrong fitting can damage the threaded insert in your bed base.

What Size Thread Are Brownies Mattress Direct Bed Legs?

Brownies Mattress Direct bed bases commonly use M8 threaded bed legs.

M8 is one of the easiest replacement fittings to source in New Zealand, with a wide range of replacement legs, castors, and furniture feet available.

What Size Thread Are Slumberzone Bed Legs?

Slumberzone bed bases commonly use a 3/8 imperial thread fitting.

Because 3/8 fittings are larger than M8 and 5/16 fittings, it is important to ensure you purchase the correct replacement leg. If you are unsure, remove one existing leg and select either Method One or Method Two above to check your thread size before ordering.

What Size Thread Are Dunlop Beds Bed Legs?

Dunlop Bed bases typically use a 3/8 imperial thread for bed legs and castors.

This fitting is commonly found on older bed bases and requires a matching 3/8 replacement leg or castor. Attempting to fit M8 or 5/16 legs may damage the threaded insert.

Frequently Asked Questions

Are bed leg threads standard in New Zealand?

No. Different manufacturers use different fittings, including M8 metric threads, imperial threads, and push-in pin systems.

M8 vs 5/16 vs 3/8: What's the Difference?

One of the most common mistakes people make is assuming that all bed leg threads are interchangeable or standardised.

While M8 and 5/16 threads have a similar diameter, they use different thread pitches and should not be forced together. Likewise, a 3/8 thread is noticeably larger and requires a matching fitting.

At Caford Castors, we do not recommend measuring the diameter or pitch of your threaded stem, as this requires incredibly accurate measurements with vernier callipers – not a ruler!

Attempting to install the wrong thread can damage the threaded insert inside your bed base.

What is the most common bed leg thread size?

M8 is one of the most commonly used thread sizes among New Zealand bed manufacturers.

Can I replace castors with fixed legs?

In most cases, yes. As long as the replacement leg uses the same fitting type and thread size, castors can usually be replaced with fixed bed legs. Alternatively, you can refer to our guide on replacing your bed legs when the attachment fitting doesn’t match by clicking here.

What if my bed uses a push-in pin?

Push-in pin fittings require replacement legs designed specifically for that system. Standard threaded legs will not fit.

Final Thoughts

Choosing the correct replacement bed leg starts with identifying the fitting your bed base uses. Whether your bed uses an M8 thread, a 5/16 fitting, a 3/8 thread, or a push-in pin system, taking a few minutes to check your existing leg can save comfort, time and money.

If you're unsure which fitting your bed requires, remove one leg and compare it with our bed manufacturer guide above before ordering replacement bed legs or castors.