Sharpening Tools Buying Guide...
Man has always had a need for sharp tools and the ability to create a sharp edge has often meant the difference between life and death. From the removal of fine shards of flint from an axe head to honing the edge of a chisel, the mechanics of sharpening have changed very little. Often seen as an essential yet unproductive workshop task, having properly sharpened tools can increase the quality and quantity of your work.
Anatomy of a Sharpening Tool
Whether using a stone by hand or a mechanical grinder, the fundamental processes involved in sharpening remain the same. By understanding these processes and what is required to create a sharp blade, the task of sharpening can become much easier and far less daunting.
Looking at a sharp blade under magnification you will see it has a straight, even edge allowing it to slice through the material being cut or trimmed.
A dull edge will look ragged, uneven and possibly even rounded over and this prevents it from cutting cleanly.
Sharpening takes this rough, uneven edge and makes it fine and straight again. This can be done using a number of different methods but they all share the same basic principal of removing metal from the blade with an abrasive.
The abrasive, regardless of whether it is a waterstone or a sheet of wet and dry sandpaper, scratches the surface of the blade removing some of the metal. The coarser the abrasive, the larger these scratches will be. Successful sharpening involves using multiple grits of abrasives in increasing degrees of fineness to remove the dull edge and create a new one. ©
Types of Sharpening Tools
There are two main types of waterstone, natural and synthetic. Natural waterstones are quarried from a few select areas worldwide that are renown for their fine consistent stone. Synthetic waterstones consist of particles of an abrasive such as aluminium oxide suspended in a bonding compound. Both types of stone work in exactly the same way although technology is now such that the synthetic stones are now outperforming the natural ones. Waterstones must be soaked before use and kept wet throughout use. Abrasive particles are released from the stone during use creating a slurry on top of the stone. It is this slurry that abrades the metal. ©View our Range of Waterstones
Like waterstones, oilstones can be either naturally occuring or man made. Arkansas stones are possibly the most common of these naturally occuring stones and get their name from the American state they are quarried from. Synthetic oilstones are composed of an abrasive such as aluminium oxide mixed with a bonding compound. Oilstones require soaking in oil before use and then the surface of the stone lubricating with oil during use. As oilstones are extremely porous, they will clog if not kept lubricated in use. Oilstones cut and wear much more slowly than waterstones and are better for use where precision sharpening is required such as with carving tools where the profile shape has to be preserved. ©View our Range of Oil Stones
Diamond is the hardest substance know to man and because of this, makes an excellent abrasive. Ideal for sharpening very hard tool steels, diamond stones are also recommended for sharpening tungsten carbide. Diamond stones are composed of diamond particles mixed with a metallic bonding agent that is then heat bonded to a flat metal plate. Two types of diamond particle are used for the production of these stones: monocrystalline and polycrystalline. Used in cheaper, lower quality stones, polycrystalline diamond particles are not as durable as the monocrystalline particles and have a tendency to break off, dramatically reducing the life of the stone. Always select the harder wearing and more durable monocrystalline diamond stone. ©View our Range of Diamond Stones
Wet grinders combine the benefits of water cooling with a slow moving grindstone. This prevents the build up of heat in the tool steel which can damage the structure of the steel and shorten the life of the tool. Wet grinders are available with either horizontally or, more commonly, vertically oriented wheels. These types of mechanical grinders will sharpen all kinds of blades and profiles but usually require dedicated jigs for each type of tool to ensure that the shape of the edge is maintained. Due to the slow movement of the wheel, only a small amount of material is removed from the blade making these excellent for sharpening tasks that require accuracy. ©View our Range of Wet Grinders
Dry grinders create much less mess than water cooled systems. Dry grinders feature air cooling rather than water cooling meaning the steel blade is not exposed to water which, over long periods of time, can cause rust. The slow moving wheels further reduce the build up heat caused by friction and the horizontal orientation of the wheel ensures a perfectly flat, rather than hollow, bevel. This flat bevel gives a stronger cutting edge to the blade prolonging the life of the edge. ©View our Range of Dry Grinders
Features to Consider When Buying a Sharpening Tool
1. Grit Size
Grit size is one of the most important considerations when buying sharpening stones. Generally given a number, particle size is measured by passing the grit through a sieve or mesh with a set number of holes per square inch. The lower the grit number assigned to a sharpening stone, the larger and therefore coarser the constituent particles. For general reshaping of blades choose a coarse grit around 220. For honing choose a medium grit around 1000-4000 and for final polishing choose a fine grit 8000+. ©
2. By Hand or Machine?
There is no right or wrong answer to this; every woodworker you ask will have their own methods and opinions. The important thing is choosing a sharpening method that you feel comfortable using and produces the right results for you. On the whole, the mechanised process is faster than sharpening by hand but lacks the soul and romance associated with the traditional methods of hand sharpening. Both methods are extremely accurate if done correctly. The method you feel happiest with is generally the right one for you. ©
3. Type of Steel Being Sharpened
When choosing a sharpening stone or system, it is important to consider the types of tool steels you intend to sharpen. High carbon steel is extremely susceptible to damage caused by heat build up so selecting a system that is cooled or will not cause the blade to heat up significantly is preferable. High speed and A2 steels are incredibly hard and require a harder abrasive to sharpen. These types of steels are not so prone to heat damage but do take longer to hone. Very hard materials such as tungsten carbide are best sharpened using diamond stones and files. ©
Tips From the Experts
1. Use a credit card diamond stone to sharpen planer blades in situ. This saves plenty of time as the blades do not need to be removed and re-set. This only works if the blades are simply dull and are not in need of re-grinding. ©
2. A honing guide is an excellent way of presenting a blade at a consistent angle to the sharpening stone. This will support the blade and prevent it from rocking during sharpening. ©
3. When sharpening a blade, make regular checks on the edge. Honing takes a lot less work than you would imagine and you could be taking metal off the blade unnecessarily. ©
4. Shaped diamond files are perfect for sharpening profiled router cutters and spindle moulder tooling. ©
The company behind the Work Sharp system has over 35 years of experience in the design and manufacture of industrial and domestic sharpening machines. Work Sharp is a system that mechanises the scary sharp method of sharpening using abrasive sheets rather than whetstones to put an incredibly sharp edge on a blade. This dry system is less messy and much faster than the water cooled grinders and is safer for both the user and the tool than conventional dry bench grinders.View our Range of Work Sharp Sharpening Tools
The Norton Pike company was formed in 1932 when Norton Abrasives bought The Pike Co, a company specialising in supplying natural sharpening stones. This combination of Norton's expertise in the area of synthetic abrasives and the quality of Pike's quarried stone meant that this new company could offer a wide range of premium quality sharpening stones. Over the years, the company has expanded and now boasts the broadest range of sharpening stones available and Norton products are highly respected by woodworkers from around the globe.View our Range of Norton Sharpening Tools
Waterstones wear very quickly and can become rutted or grooved when used for sharpening V-tools and gouges. Regular maintenance with a flattening stone will keep the stone surface flat and give better sharpening results. ©
Always check grinding wheels before use. Ensure the fastening nuts are tight and check for visible signs of damage such as cracks and overly large chips. Never use a cracked grinding wheel as it may break in use. ©
When using sharpening stones, always clean the blade thoroughly between stone changes. This will ensure the finer stone is not contaminated with larger grits from the previous stone. ©
Check new grinding wheels for faults by gently tapping the wheel with a wooden handle. The wheel should ring. If it produces a dull sound, the wheel may be cracked or flawed and should be discarded. ©
Grinding wheels can become smooth "glazed" with use. This can be reversed by using a dressing stone or tool to roughen up the surface of the wheel. ©