Clarke Contractor – Twin Blade Saw Multi-bladed Cutting
As a kid I remember being slightly confused by the idea that some aeroplanes had contra-rotating propellors. I wondered how they would work. In fact, I think the idea of contra-rotation is counter-intuitive, but once you think about it, there is no reason why it shouldn’t work. In aeroplanes, contra-rotation stops the torque effect of a single rotational force like a propellor, and in a saw like the Clarke Contractor Twin Blade Saw, it means that there is no “kick” effect, particularly when you start a cut. So, just how do they do it and how can you, the user, benefit from it? I will start by looking at the saw itself.
In truth, the saw looks more like an angle grinder with a blade attached than the more common version of a portable circular saw. But bearing in mind the jobs for which this saw is designed – this is a plus point. The tool is gripped by the body with the trailing hand and the leading hand holds the auxiliary handle. The leading hand does most of the work guiding the cut while the trailing hand steadies and supports the saw. The body is quite substantial, but is still small enough for those with average sized hands like mine. A substantial cast alloy gearbox housing holds the “business end” and attached to that is a very strong steel blade guard that covers the top half of the contra-rotating blades. The bottom of the blade is guarded by a clear plastic, spring-loaded guard. This has a large tab handle that is used to move the guard away from the blade on some specified cuts. Looking down on the top of the blade is a strong steel
bracket with a threaded hole to hold the large, shaped auxiliary handle. This handle has to be here where it is ideally placed to be right over the cut so that the cut can be accurately placed.
Just forward of the handle is a knurled plastic wheel whose function I couldn’t guess until I had read the instructions. When cutting metals, a stick of lubricating substance is placed into the hole at the base of this wheel and the wheel is then turned to feed the lubricating stick down to the blades. This is clearly a vital ingredient for preserving the blades and limiting sparks. Six sticks of lubricant are provided in the kit.
The switch is a safety-slider type that needs the operator’s thumb or finger to be on it while cutting. As soon as the pressure is released the saw is switched off – for some demanding cutting operations this is a very good safety feature. As mentioned earlier, the yellow ABS body is quite substantial, and halfway down, there are two round apertures so that the motor-brushes can be replaced easily by the user. A pair of brushes is supplied in the kit, so it seems like Clarke is expecting this tool to have a hard working life. A shortish 2.5 metre length of cord with a quality moulded plug completes the run-down of the tool. Looking at the specifications it is clear that this saw is quite a specialized tool – it is not a standard portable circular saw with an extra blade. The motor is powerful at 650 watts and the blades’ diameter is only 125mm or 5 inches. The maximum depth of cut is 28mm – so don’t expect to be chopping up huge items.
Where this saw comes into its own is in quite specialized applications like cutting pipes, steel and alloy sheet and other metals. These are often encountered on demolition sites and industrial building sites when refurbishing or remodeling. Cutting up old steel garage doors, for example, is right up the Twin Blade Saw’s street.
There are other portable saws on the market that will cut metals by virtue of the specialized TCT blades that they use, what they don’t have is the contra-rotating blades of the Twin Blade Saw. Used
carefully, these blades virtually eliminate dangerous kickback when cutting very hard materials and the design of the saw allows it to get close to the target cut. For example, pipes that have been attached to a wall can be cut without damage to the wall and very close to where the ideal cut would be. Also, there is no need to worry when cutting wood with nails or screws in it as this saw slices through both with ease. I started testing the Twin Blade Saw, rather gingerly, on a piece of softwood, just so that I could get a “feel” of what it would be like. The motor, although powerful, is reasonably quiet and vibration free, and soon has the blades up to full speed. Once this is achieved, the saw can be advanced onto the work. The spring-loaded guard is pushed out of the way and the cut proceeds. In the wood, the cut was effortless as you would expect. I ended up virtually using the saw as a sculpting tool to make gaps for imaginary piping in a joist for example. I tried some copper pipes next, remembering to add the lubricating sticks. These cut very easily as well, with no kick back and leaving a shiny polished, burr free finish on the cut ends of the pipes. I only had a thin 1.5mm thick sheet of mild steel to cut in my testing stock, but with a little practice, I could follow a line – slightly curved or straight, with ease, again with a clean,burr free cut. The kerf, as you would expect from two blades, is wider than a single blade, but the advantages of a zero kick-back saw far outweigh any loss of metal with this twin blade saw. The whole kit comes in a black blow-moulded case with enough space for everything and also a box spanner to change blades when needed. The case looks and feels pretty “white van proof” and also has strong metal latches.
Clearly, the Clarke Twin Blade Saw is a specialized piece of kit aimed at certain trades that need to cut a variety of materials in the course of a working day. But I think that it could also be useful to jobbing builders who occasionally encounter difficult cutting jobs that no other saw could tackle easily. My steel garage door example comes to mind. I think it is a good piece of kit that makes specialized cutting jobs a lot easier to achieve. It would also be great for cutting kitchen worktops to fit sinks, hobs etc as the twin blades give a nice clean cut.
18 ToolBUSINESS+HIRE
www.toolbusiness.co.uk Independent Review by Peter Brett
Reply No. 209
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36