|Brent's Sharpening Pages|
|Microbevels front and back.|
|Use a jig.|
|Copyright © 2002-15, Brent Beach|
During this time I also read many web forums on sharpening - forums in which strongly held opinions are presented.
To broaden my understanding I have read a number of books on Metallurgy and Metallography. Metallurgy is the study of the production of steel. Metallography is the the study of the internal structure of metals.
All this to understand how best to sharpen tools.
Sharpness in tools means the right balance of edge sharpness and edge durability. We want to be able to plane several hundred feet between sharpenings.
Finding the right included angle is a matter of experimentation. You can begin with a standard angle and experiment with larger and smaller angles and see which angle works best for the wood you are using and your style of working.
Other sharpening systems - different combinations of jigs, abrasives, angles - will either not produce a reliable edge angle, or will produce a less durable edge, but most likely a combination of both.
So, the question is not whether you use a jig. You do. How good is your jig?
A jig that is unable to meet both of these criteria will produce inferior tool edges.
We will see when we discuss steel condition at the edge that fine abrasives cause less damage to the crystal structure of the steel. Very fine abrasives are able to remove steel with almost no damage to the steel at the edge. The result is a tool that is as durable as possible given the steel in the tool.
The finest abrasives, those that produce almost no deformation beneath the scratches they produce, remove metal very slowly. Much too slowly to be used on an entire bevel. They can only realistically be used if you use microbevels.
Many people try to solve this problem of slow metal removal by combining grits. You will see elsewhere in these pages the actual grit combination in an abrasive labelled as 0.5 micron. In fact, it is mostly particles over 45 microns. Such an abrasive leaves subsurface damage associated with the 45 micron grits. It is completely inappropriate as a final abrasive. People who use it will find their tools dull very quickly.
The Sketchup model of a sharp edge (on the left) and a worn edge (red, on the right) clearly shows the challenge a sharpener faces. Both surfaces of the tool have been modified during use. Sharpening using a jig like mine will quickly return the tool to the sharp state. Other methods probably won't. For example, any freehand method will instead take you somewhere between sharp and dull (closer to dull). Any jig that does not do back bevels will get you somewhere between sharp and dull.
You can use a dull tool. You did use it while getting it dull in the first place. Why work with dull tools all the time, when sharpening correctly is so easy. Watch this video of me using my honing system to see how quick and easy it is.
Check out the introduction to Sketchup models that shows honed microbevels and wear bevels.Sharpening
Examination of sharpened blades over 8 years has convinced me that a combination of 3M Micro-abrasives on glass and a simple shop-made jig produces the best quality edges. No other sharpening system I am aware of can produce edges this good. You will see the photomicrographs in these pages that prove that this combination works. What other sharpening system shows you photomicrographs of their honed edges?
People have sent me pictures of jigs they have built.Testing
You have all read the claims by tool makers about how their blades last 5 times as long as ... blah, blah, blah. Have you even been shown their tests?
Tool testing has three phases: tool preparation, the test, and test evaluation.
Sharpen the plane blade to the same fine surface on both faces. For most tests I show microphotographs of both the front and back of the blade before the test.
A standardized test (all tests have used wood from the same part of the same tree!) means that the test conditions are the same for all blades.
These are the shavings produced during part of one test.
The ability to measure plane blade wear to the ten-thousandth of an inch, using the QX3.
In this section, see photomicrograph test results -- before, during and after -- of over 20 commonly used plane blades, both antique and modern.
You decide which blades are the most durable. (None of that "our blades lasted 5 times longer" stuff.)The QX3.
A description of the Intel QX3 microscope.
Some people might be interested in the microscope itself. This section also contains an introduction to the images of plane blades, knives, razor blades.My other pages.
In addition to plane blades, I also sharpen saws and chisels, and travel.Links.
Other people who are sharpening and testing plane irons.