Clipper Blade Sharpening
You can search for hours on end on the internet to find out exactly how a blade should be sharpened. Company A will say all blades should be ground flat, company B will say all blades should be hollow ground, company C will say all blades should be flat lapped and company D will say all blades should be hollow lapped. Hopefully this will help you decide which method is most suitable for you.
Essentially, there are 3 ways to sharpen a clipper blade. There are loads of ‘cottage’ ways to TRY and sharpen a clipper blade, but there are only 3 that are worth considering and that will not completely ruin a blade. They are: a grinding wheel, a lapping wheel and an oil stone. Heres a brief description of each. The descriptions are of the methods relative to sharpening a clipper blade.
Disregarding the more complex oil stone, an oil stone in its simplest form is a block of either quarried or man made stone. The top surface is perfectly flat and comes in various different grades. Allot of the most useful and popular oil stones are diamond plated. Although this sounds fancy and expensive it is the same as an oil stone with the addition of a steel, plastic or resin plate which is coated in fine diamond grit. A grade denotes the size of the grit on the stone and therefor also denotes the smoothness or coarseness of the finish it leaves. A finish is achieved by rubbing the work piece surface back and forth on the stone. The plate may have a series of holes cut in it that capture the debris as grinding takes place. An oil stone is comparatively smoother than a grinding wheel but similar to a lapping wheel.
A wheel, made from aluminium, with tiny ridges and pits can be anything from 12 inches to 25 inches in diameter. The wheel itself is just a carrier for an abrasive. The pits hold the abrasive. Abrasives can be a diamond solution (wet or dry) or a paste made of fat and graded sand (silicon dioxide). The abrasive is applied and then the work piece surface is ran back and forth across the radius of the wheel. The coarseness of the cut is determined by the size of the sand particles in the paste. The wheel rotates comparatively faster than a lapping wheel and is comparatively rougher than a lapping wheel or oil stone.
A wheel made of cast iron. It is extremely smooth, except for grooves which run along the radius to drain excess abrasive and carrier. The wheel rotates comparatively slow and is comparatively smoother than a grinding wheel but similar to an oil stone. The workpeice is held inside a rotating ring by a jig, loose weight or holding arm depending on design. The workpiece then rotates on top of a rotating wheel creating a double rotation that ensures even sharpening. An abrasive solution is then applied to the wheel that depending on grade, polishes and sharpens the surface. A lapping wheel is comparatively smoother and rotates comparatively slower than a grinding wheel.
So there we have the three types of method. Next thing to consider is concavity or ‘hollow grind’. The reasons for having a concaved blade are largely hazed over. It would appear that many clipper blade sharpening companies/individuals have a limited understanding for the reasons. They know that a lapping wheel leaves a comparatively smooth finish and takes less material off (which is obviously better) and therefore rave about it and spout the adjoining ‘hollow ground’ without knowing the reasons. Again, the following is an understanding, derived from years of experience.
To decide whether a blade should be concaved or flat depends on the way the two blades are tensioned together.
All horse and sheep (aside from heineger, maverick and oster stewart blades) have a tension set that pulls the blades together from one single point in the middle. Bearing in mind, we are talking microns (1 micron – 1000th of a mm), when tension is applied it pulls the blades together in the middle of the blade which bends the blade (again bearing in mind we are talking 1000th’s of a mm). If this blade is flat, the pressure will be concentrated in the middle and therefore the blades may blunt quicker. This is where a hollow grind is preffered, if the blades are hollow, when they are pulled together, it will pull them flat, making sure wear is even and spread across the whole blade. This even spread of wear means that the blade should last longer.
Other blades are tensioned evenly across the cutter, so there is no need to for the blades to be concaved. This includes most small blade and the exceptions mentioned in the above paragraph.
Above are the two ideals for the blades but because the differences are so minimal, both methods are acceptable for any type of blade. The variables that make a blade blunt are such a substantial factor that the concavity or flatness of a blade is massively insignificant. For instance, a blade that the factory sharpens according to its ideal but is over tensioned, under lubricated and clipping through dirty hair will blunt much, much quicker, than an old blade sharpened contrary to the ideal, which is tensioned properly, lubricated and cleaned often and cutting clean hair. To add to this, not all major and well known blade manufactures hollow lap their blades at the factory, some are ground.
Now that concavity and flatness have been discussed you must now decide whether you want them to be lapped or ground.
There is no definite answer to this, it is up to an informed individual to decide what is best according to their needs. Lapping is generally smoother and takes comparatively less material off the blade, meaning it could be sharpened more times before all the material has been ground away. Grinding is different. Sharpening a clipper blade using a grinding wheel requires more user skill than a lapping wheel but is alot quicker. Some modern lapping wheels available on the market almost take away the need for any skill, where as without skill, a blade can be destroyed in seconds on a grinding wheel. If your blade has been hand ground, it has been done by an experienced blade smith. You cannot guarantee this with a lapped blade. In most applications, grinding is fine, if a blade is rusty and pitted, you would have to grind (unless you have forever and a day to wait for your blade to be sharpened)
Once blades are sharpened, some types of blade require assembling and tensioning correctly before they can be used, unfortunately this cannot be taught in writing! This comes from experience!
Aside from an oil stone, the equipment to lap or grind blades is expensive. An oil stone takes A LOT of effort but is cost effective if you have the time. If you do not have the time or finances to buy proper clipper blade sharpening equipment then you should consider sending your blades to us!