Sharpening Techniques

It never ceases to amaze me how many carbide bits we sell, both in router bits and drill bits, as well as saw blades, planer knives, etc. My question to you is "What do you do with this item when it is dull?" The answer more times than not is that you throw it away. Did you know that not only are there sharpening services available that will bring your carbide back just about like new, but in most cases you can do your own sharpening and save yourself lots of money both in the sharpening as well as the cost of the replacement.

Let’s first look at why we should sharpen. This is easy. Have you ever tried to drill or cut with a dull piece of carbide. It doesn’t do a very good job, and you can end up ruining the material you are working on. A sharpened piece of carbide will go through your material like butter, and put less strain on the tool's motor. Lets take a look at each type of carbide cutting instrument and see how we keep them sharp.

Let’s start first of all with drill bits. These can be both carbide or non carbide, and the first and easiest thing to do is just throw them away due to their relatively low cost. Although I’ve seen many devices to keep drill bits sharp, the best and most cost effective seems to be the Drill Doctor. Depending on which model you buy, you can sharpen all of your drill bits up to 3/4". Although the cost is up there (starting around ) this is a tool that will pay for itself quite quickly if you use a good amount of drill bits. You’d be surprised at how fast the dollars add up for the replacements.

Next, lets look at router bits and saw blades. The key here is that the price of the router bits and saw blades is quite a bit more than that of a drill bit, and you should do anything possible to preserve it. Many router bits are upwards of each at cost, as well as most 10" blades going for over The easiest way and the best method for sharpening these items is with diamond, and you can accomplish this yourself by purchasing a DMT Sharpening Stone. These are flat surfaced stones of varying sizes, that are impregnated with diamond so that the entire flat surface is used for sharpening. You simply need to apply some water as a lubricant directly onto the stone, and gently rub the flat part of the carbide on the wet portion of the stone to bring it back to its original sharpness. A good quality blade or router bit should be able to be sharpened at least 10 to 15 times before being disposed of.

Lastly, we have planer knives. The trick is to keep an even edge on the knife, or it is worthless. This is accomplished with the use of a knife holder along with a whetstone. There are machines that will assist in performing this task, such as the Delta Sharpening Center. It can be used to sharpen countless items, and when used with the knife grinding attachment, makes quick work of those planer knives. Carbide knives for the planer are probably the most expensive single piece of carbide you will own, and as all carbide should be kept nice and sharp, which makes this machine a must if you own a planer or jointer.

Obviously, sharpening is an art that goes deeper than I just laid out above, and there are many good books on the subject. The bottom line is that most people are afraid to try it themselves, due to the possibility of damaging the carbide. But thanks to some of the items listed above, it has become much easier and something you should definitely give a try yourself. If you have comments or questions about this or any other topic, feel free to e-mail me at dbarnett@internationaltool.com. Speak to you again next month!

Till next month,

Dean "The Tool Guru" Barnett, President
International Tool Corporation

Email the Guru.

Read previous months' tips:

Surface Planers
Finecut Finishing Saw
Production Routers
Biscuit Joiners updated 1/13/99
Cabinet Tablesaws updated 1/13/99
Slide Compound Miter Saws
Mid-Sized Plunge Routers
Cordless Drills
Detail Sanders
Random Orbit Sanders
Brad Nailers
Hammer Drills
Saw Blades
Reciprocating Saws
Routers