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Radius Master belt grinder

Expensive - but what a tool!

by Julian Edgar

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At a glance...

  • Superb belt grinder
  • Versatile and quick
  • Expensive
  • Does all that it is advertised to do
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If you fabricate items in your home workshop, it’s likely that there are a few power tools that you use very frequently. In my workshop, those tools are the drill press – and the belt grinder. In fact, when I sat down and analysed where my power tools were letting me down, it was the belt grinder. When I am fabricating, I use it almost constantly – for deburring, shaping, smoothing and sharpening.

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Trouble is, my belt grinder – a Multitool attachment for a bench grinder that I’ve owned for decades – has a few deficiencies. It doesn’t have the sheer grunt needed when shaping thicker steel, and it doesn’t have the ability to work on the inner diameters of smaller radius bends. Further, it lacks guides that allow items to be easily ground square on the belt. The Multitool has been a fantastic tool over a long time, but now it was limiting what I could do.

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So off I went and bought a new generic belt sander/grinder to replace the Multitool. But it was hopeless – not enough power and worse still, a low belt speed that made grinding and sanding far slower than the original Multitool. Even on timber, I thought its performance was pretty bad.

I then looked second-hand, but every machine I could fine had the deficiencies of either the Multitool or the machine I’d attempted to replace it with.

Then I found the Radius Master. I took a very deep breath when I saw the new price (AUD$2100 – shop around to get this price), did some investigating – and then made the decision to buy.

Now, a few months later, how is the machine working out?


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The Australian designed and developed Radius Master uses a unique, patented design.

The 50 x 1220mm belt wraps around a series of rollers in a roughly triangular shape. One stretch of belt between the rollers is backed by a platen, allowing surface grinding (ie flattening). Another length of belt is not backed by any surface, so can be used to sand slight curves.

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The main rollers on which the belt rides comprise 2 inch (50mm), 3.5 inch (89mm) and 8 inch (203mm). These different size rollers allow the grinding of different radii. For example, the large roller is excellent when hollow grinding, while the smaller rollers allow you to get into tight spaces.

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The smallest roller is located on a rotating mount. Pushing in a pin and rotating this mount allows the selection of another two rollers, the smallest of which is just 1 inch (25mm). This smallest roller is excellent for notching (fish-mouthing) tube. Note that no adjustment of the belt is necessary when making this roller change.

Each of the rollers can be covered as required by swivelling guards.

The head of the Radius Master rotates so that you can bring whichever wheel you want to the front. There are also locking positions to have the platen vertical or horizontal.

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Furthermore, if you wish, you can rotate the whole machine so that the belt is moving horizontally, not vertically.

Powering the belt is an industrial-sized 1.5kW direct drive electric motor. Compared with the bench grinder Multitool I have been using, the Radius Master’s motor is three times as powerful.

What you get

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The Radius Master is designed to be bolted to a concrete floor. It comes with the stand and floor mounting plate.

In addition, provided are a tilting table for notching tube and a tilting tool rest that works with the flat platen. Both tools are easily and quickly removable; they store on the stand.

A single sanding belt is also provided.

Using it

The Radius Master is a joy to use.

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Probably the single best aspect is its power – and so the speed with which jobs can be done. With the Multitool, I’d got used to applying only very light pressures, or grinding only one part of the job at a time. Push that machine any harder, and it would stop!

With the Radius Master, there’s so much power that you can just chomp through the material at an incredible rate. It is far faster than an 8-inch bench grinder in shaping metal, and can of course do things that no grinder can do.

Radius Master claims that you can put 25mm radii on the corners of a 50 x 6mm bar in just 35 seconds… and I believe them!

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The Radius Master’s grunt also means that it can drive power-hungry belts like those made of Scotchbrite material. These belts, that are awesome for polishing (eg cleaning-up aluminium), are relatively stiff and so require lots of power to drive them. The Radius Master will drive even a coarse Scothbrite belt at speed – and still have enough power left over to do the work, even at high working pressures.

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The second huge advantage of the machine is the selection of different diameter wheels to which you can apply the work. Having five different radii means that you can achieve results simply impossible with other machines. For example, after I bent some 30 x 5mm steel bar to make a 45-degree bracket, I ground flat the outer surface and then also the inner radius of the bend.

Shaping an alternator support bracket that comprised a curved shape cut from 8mm steel plate, I was able to belt grind both the inner and outer edges, the smaller Radius Master wheels easily ‘fitting in’ the curves.

The third advantage of the Radius Master over any other belt grinder I have used is the belt tracking. The belt tracking is so good that you can grind using the edge of the belt – for example, notching a plate. You need a very good quality belt to do this (otherwise the edge of the belt gets chewed away) but it is quite possible.

Other pluses of the machine are the speed with which belts can be changed, and the stability and security of the stand.

And disadvantages?

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The biggest disadvantage is one that goes with the territory of power and speed – the Radius Master can go through belts pretty quickly. In fact, the belt that was supplied with the machine lasted me only a few hours. That said, this belt was probably too fine for the work I was doing.

However, good quality belts are available from an eBay supplier for only about AUD$5 each.

Another minor disadvantage is that when using a thick Scotchbrite belt, the guards over the wheels can touch the belt, so you need to remember to not close the guards when using this type of thick belt.


The Radius Master is a brilliant tool.

It does everything its manufacturer states it can do, and transforms the speed with which jobs can be completed. It is bloody expensive, but in home use it could be expected to last for pretty well ever. I figure that if I put a dollar in a tin every day I use the Radius Master, after four or five years it will be paid for.

Highly recommended.

For more information, including videos of the machine in action go to

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