OptiGrinder 200mm Slow Speed Bench Grinder archive
Monday 13 May 2013
Anthony Bailey and Mark Baker gave the 200mm OptiGrinder and the latest fine-grade CBN grinding wheel a thorough workout
The OptiGrinder is a solid, well-made piece of kit, that is beyond doubt. It came in a well-packed cardboard box, and once out of the box all that was needed was to fix the top spark guarding and the rest assemblies on each side of the grinder guarding. The shielding is the standard clear tilt safety Perspex-type product and the toolrests are simple screw on items. That said, they function, but are not the most sturdy I have come across. Having said that, the beauty of them is that they can easily be removed in order to fit platforms and other sharpening systems we turners prefer to use anyway. That can't be said of some other units which require you to grind off the rests.
In useOnce assembled and switched on there was an unsatisfactory degree of vibration on the grinder. Careful examination showed the plastic base had got knocked in during transit, but once removed and reset things were a lot better, but it was further improved by removing the thick and somewhat squidgy rubber feet. We also bolted the grinder down to a couple of wooden battens and placed the whole thing on some rubber routermat. An element of customisation got the best from this precision piece of kit. There was no vibration and the wheels ran true. It comes equipped with one narrow grey K36 AlOx wheel and a wide white K80 AlOx, which are both good quality close-grained wheels. We both prefer 200mm grinders for sharpening tools and this slow-speed version is excellent for this purpose. The narrow one certainly hogged the metal away for quick shaping and the white fine-grade wheel has proved to be ideal for sharpening.
VerdictOverall, a well behaved, quiet machine at a sensible price. If you are looking for a new grinder that is going to be well used, then this is worth looking at.
CBN grinding wheelsMark and I always have a potential issue with bench grinders as dry grinding can cause overheating easily and the edge finish using some of the wheels - usually the cheaper end of the spectrum - often isn't that fantastic. Much of this is dependent on the speed of the grinder and also the grit grade and, as mentioned, the quality of the wheel used. There is some debate as to whether high or low speed grinders are best. I think that the slow speed grinders offer many people more control with what I can see as no downside on the cutting edge quality. But we wondered if the sharpening process can be refined and enhanced even more?
OptiGrind have developed precision CBN wheels with optional extra matching aluminium bushes available to suit specific shaft diameters. What is CBN? The answer is Cubic Boron Nitride, nearly as hard as diamond but far better suited to grinding HSS tools. Normally this would be specific to industry but it has now made accessible to consumers, too.