One of the standout features on Melbourne Tool Company’s low angle bench planes is the Norris-style adjuster. If you’re new to hand planes, it might look like a simple thumbscrew—but it’s much cleverer than that. This mechanism gives you fine, reliable control over your blade’s depth of cut and lateral alignment, making the plane easier to use and more precise.
Let’s break down how it works, why it matters, and how to get the best out of it.
A Quick Bit of History
The Norris adjuster takes its name from the English plane maker Thomas Norris, who introduced it in the early 20th century. At the time, many wooden and early metal planes used simple wedge systems to clamp the blade in place, and adjustments to the blade were made with a light tap of a hammer. The Norris design cleverly combined fine depth and lateral blade adjustments into one mechanism, making it practical to fit to low-angle planes. It was innovative then, and it’s still a popular solution today.
The Three Parts of the Norris Adjuster
On MTC low angle planes, the Norris-style adjuster has three main components working together:
The Thumbscrew – A long screw with two different threads cut along the length, and a knurled wheel at one end.
The Pivot –swivels from side to side in a bore in the main casting of the plane, and has a thread that matches the larger of the two threads nearest the wheel of the Thumbscrew.
The Adjuster Pin – Running on the smaller thread at the end of the Thumbscrew, the Adjuster Pin fits into a hole drilled into the blade.
How It Works in Practice
Lateral Adjustment: The lateral adjustment is pretty straight forward. The Pivot acts as a fulcrum, the knurled wheel of the Thumbscrew as one end of the lever, and the Adjuster Pin as the other. Pushing the Thumbscrew wheel to the right moves the Adjuster Pin to the left. Because the Adjuster Pin connects to the blade at the rear, and the blade pivots around the front (because that is where the clamping force is applied), the blade will skew to take a deeper cut on the left.
Depth Adjustment: The Thumbscrew passes through the Pivot on a thread, so turning the Thumbscrew clockwise moves it forward, advancing the blade. The thread is 1.5mm pitch, meaning for each revolution, the Thumbscrew moves 1.5mm forward or back. This is much too large in hand-plane world!
So the clever solution is to have the Adjuster Pin attached by a thread as well, but at a smaller pitch (0.8mm). Now for every full turn of the Thumbscrew, it moves forward by 1.5mm in relation to the Pivot, but the Adjuster Pin moves backward by 0.8mm. So the blade moves forward only 0.7mm, or less that 1/32 of an inch.
Of course it seems that the whole Thumbscrew could be made with a 0.8mm thread for a similar outcome. But threading the whole thumbscrew with the finer, smaller diameter thread would be weaker, and we’d still need a way to attach the Adjuster Pin to the Thumbscrew.
Dual Control, One Mechanism: The beauty of the Norris adjuster is that you don’t need separate levers or screws for lateral and depth adjustments—it all happens in one compact system.
Tips for Using the Norris Adjuster
Keep the Blade Loosely Secured While Adjusting – If the lever cap is clamped too tightly, the blade won’t move. Back it off slightly, make your adjustment, then snug it down again.
Work in Small Turns – The adjuster is quite fine, but small changes to blade projection can make big differences, so keep adjustments small.
Always Advance the Blade Last – Always make your final adjustment advancing the blade. If you need to retract the blade, do so slightly more than needed and then advance the blade to the desired setting. This way any slight ‘backlash’ in the screws is already taken up and will stop the blade slipping backward with use.
Check Against the Sole – Hold the plane up to the light with the blade protruding just a fraction. Adjust laterally until the edge looks even across the mouth.
Don’t Force It – If the adjuster feels stiff, check that the Adjuster Pin is properly seated in the back of the blade, there is no grit in the Pivot bore, and the lever cap is just slightly loose.
Why It Matters
A plane is only as good as its ability to take consistent, controlled shavings. The Norris adjuster gives you that control with a simple, elegant mechanism. For beginners, it takes the mystery out of blade setup; for experienced hands, it makes fine-tuning second nature.
At Melbourne Tool Company, we’ve included this system on our low angle planes because it strikes the perfect balance between precision and simplicity. Once you get the hang of it, adjusting your plane will feel smooth, intuitive, and reliable—exactly what a good hand tool should be.