3 Head Design Sanding Units
In our 1999 pricelist we launched an imported 5 head design rotary sander which set a new standard of both speed and efficiency in sanding machine design. It was radically different in that it allowed more aggressive rotary sanding activity than had previously been possible. Up until that point, the industry had been limited to a single 405mm disc at either 198rpm, 350rpm or 398rpm [based on major machine data sheets] as standard and so had experienced the ‘drop’ in power from belt and edge sanders to lesser powered rotary sanders. Spending hours with an orbital is the right way to use them but it is a mind numbing period. The multi-head design was fresh and new and offered considerable improvements in efficiency. Those who adopted the system were able to complete the sanding work in a much shorter period of time using a variety of combinations.
The benefits of multi-head machines are many fold to the sanding community. Basically they save large amounts of time, cost less to use and give a burnished finish even on timbers that tend to bruise more easily. Now that there are locally produced heads the entry cost to this technology has dropped by over 75% which is a great bonus to the industry. Originally, the initial down-side was an up-front cost in the $5,000.00 region. [bear in mind that some systems are over $9,000.00] Because the technology is now nearing 5 years old it is no surprise that we now have two Australian versions. The South Australian “Turbo Disc” and the “VTEC” heads. Both are excellent innovations.
The VTEC head is a three head design. It takes the ‘free running’ principle but instead of using five heads it adopts a larger surface area which tends to make the head easier to control while cutting aggressively. It’s base is heavy and this allows for smooth sanding activity and strong contact to the sanding face. The three heads spin freely which is a key element in the design. Because they are 150mm diameter they are a good cutting area. The individual heads reach up to two to three times the speed of the main disc. This is because of their placement inside the disc design. Three heads cutting over each other in a ‘rotary-circular pattern’ leave very few marks and yet are aggressive enough to remove cross cut marks and the like. For example, having cut a Jarrah floor with a 40grit belt a sanding company found that it was easy to step straight onto a VTEC equipped machine and remove the marks and begin burnishing quite quickly. In practice a multi-head will save around a day on a 100m2 job when you get used to the change in method.
The powerful action allows the operator to capitalize on the rotary sanding action as was never before possible. Literally, this head fits onto the existing rotary sander; be it a Polivac or a Canterbury & from then on the sander may be used in a much more powerful manner than previously. Obviously, because you can keep your existing sander and simply upgrade to the head, there is a considerable saving over purchasing a new machine.
The change in method daunts some people which is understandable. Having been used to using a standard rotary method for some years the idea of using a rotary machine at an earlier point in the sanding process can appear strange. You also need to get around the new action and cannot ‘throw’ the machine around in quite the same manner as before. Yet knowing that with each rotation of the base plate you are achieving much more is a great feeling and the finished results speak for themselves.
The Turbo-Disc is a South Australian head designed around the five head principle that we used in our original machine. The head is designed to either fit directly onto a Canterbury sander or may be purchased with a new design Canterbury which has been geared for the 5 head turbo-disc design. It has been found that a five head design works well over a broad range of timbers when used with a slightly slower model than the usual 350rpm machine however this is generally applicable in the eastern states with stringier and softer timbers. In WA we have found that the 5 head design has worked equally well [if not better] on the existing Canterbury designs at 350rpm. This in turn suggests that, due to head placement the Turbo-Disc heads are moving at around 7-800rpm. This becomes a powerful burnishing action and again leaves very little marking while fully capable of cutting cross-cut marks off the surface.
Both heads have several advantages over the original single disc. The design allows for removal of chatter marks by simply using a lower entry grit and spending a little time on the marks. Sanding marks, even from cross-cut are not a great problem though this is governed by the depth of the mark as always. However in comparison to the usual head clearly the multi-head designs remove these marks much more easily. Swirl marks are always a concern and all rotary users become very aware of these marks early in the learning process. The possibility of marks is reduced dramatically when this system is adopted.