furniture making techniques and tool use. Close up of a Stanley Bailey type wood plane taking a shaving and showing handling technique
 

Sharpening

Sharp tools are a pre-requisite for woodworking yet so much mystique surrounds this basically simple subject, especially with plane irons and the steel cabinet scraper.

 
 
Close up of wood working plane blade bieng worked on a Japenese water stone
 
 
The Plane
Rasp,File & Scraper
The Bench Tools
Setting up a work station
The Drawing
Templates
Setting out
Joinery solutions
Profiles and Piercing
 


 
 

Sharpening chisel type tools.

    Chisel type tools includes plane and spoke shave irons as well as chisels, a plane or spoke shave is basically a tool with a chisel type iron held at a specific angle and the principals behind their sharpening are identical, however, there is an extra refinement required for the correct functioning of the plane irons that is covered after the fundamentals of sharpening chisel type irons.

 

 
    Detail of the survey of a chisel type wood tool. Preparing for working on a sharpening stone    

    The picture above shows the face of a chisel held up to the blade of a small square to check the flatness along both the length and width of the chisel face. Survey the tool surface in this way to check for any bulges or raised areas. Slight hollows are a fine thing, as long as they are slight.
The picture below shows the ideal condition (with a brand new chisel, fresh from the wrapper). The chisel face has been worked for a few seconds on an inexpensive industrial diamond sharpening stone. The bright areas around the outside edges are where the chisel rubbed with the diamond stone, the darker areas are very slightly hollow, this is the perfect condition for a chisel type blade.
The reverse of these light and dark areas is, of course, the opposite of what you want and you will need to spend time on a lapping stone to flatten a chisel in such an unfortunate condition.

Picture of the face of a woodworking chisel during working on ato shapen the tool water stone          
    Next check that the bevel edge meets the face of the chisel. The left hand detail in the images below is correct, the bevel meets the face of the chisel. The right hand picture shows the bevel edge not meeting the face of the chisel. This is one of the most common reasons for a chisel not working correctly and is usually caused by raising the face of the chisel from the sharpening stone while removing the burr created by working the bevel edge on the sharpening stone.
Detail of the correct result of working a chisel type iron on a sharpening stone
Detail of the wrong result of working a chisel type iron on a sharpening stone

 

When the tool face is flat and the flat meets the bevel edge, the tool will perform properly. There is no "gray area" here, the tool is prepared correctly or it is a waste of your time using it.

The clip on the right shows the 1½ " chisel, the work horse of the chisels, in action cutting tenons and cleaning shoulders. This very efficient and simple chisel task is completely dependent on the chisel being in the correct condition.

The clip below demonstrates the sharpening of a new chisel (a Marples Blue Chip) .

 
 
   
       

The steps to sharpness :
1.Work the flat face of the blade on the diamond sharpening stone, look at the face periodically to read what is happening.
2. When the face is flat you will be able to read this from looking at the face of the blade and you will feel a slight burr when feeling from the bevel edge.
3. Strop this burr to remove it on a piece of leather.
4. Work the secondary bevel on the stone until you just feel the blade cut into the stone (this is a matter of sensitivity in your touch.... just be aware and you will feel the chisel cut the stone... stop as soon as you feel the chisel cutting the stone). Strop the burr on the leather to remove it and you are in business with a very sharp edge.
 
"The thing about 2nd hand chisel type irons"
 

   The demo above dealt with a new chisel, anything you did not buy new for yourself should be considered 2nd hand and may have a major unseen problem. The common practice of grinding chisels on high speed grinders, the usual workshop variety with the two wheels, can "burn" chisels all to easily. When a chisel is "burnt" it turns a dark blue color and, depending on how rough handed the operator was, this blue area can vary from as little as a 1/4 inch to a 1/2 inch or more and indicates that the temper of the steel has disappeared from said area of the tool, to make things worse the blue color is just a surface coloring that can be wiped away leaving no indication that the tool will no longer hold a decent edge and should now be called a screwdriver.
Having said that, there are some good deals in the 2nd hand tool market, especially if the tools were used professionally. The subject of grinding chisel type irons will be looked at separately after the treatment of plane irons

 
Sharpening plane irons
      Contrary to popular belief the sharp end of a plane iron is not square to the sides of the iron. The cutting egde of the plane iron is in fact a part of a perfect circle.......that's the idea, in practice what you do is understand the geometry below and give it your best shot and perhaps refine your technique over time. This geometry, when applied to all the plane type tools, leads to an ability to confidently tackle wild grain in your materials. The "fine" in fine furniture refers to "fine woods", collectivly known at the bench as wild grain. Without a properly prepared plane iron you will have trouble with wild grain
   



    So that you are clear what I am talking about in the video: the illustration on the left shows the side view and face view of the plane iron. It's on the secondary bevel that you read the amount of curvature, the illustration is a bit exagerated so you can see that there is a slight curve on the cutting edge. The actual curve is part of a circle that would be a few feet in diameter. Creating this shape produces a slight curvature on the sharpening stone as well (of course) so only plane type irons can be sharpened on this face of the stone (more on this later).
 

 

 

However counter intuitive this may seem; to be using a curved blade to produce square faces and edges, it is the fact of the matter. For example, close examination of 18th century tables, particularly on the underside of the top, will always find evidence of the boards being worked with a plane with a curved cutting edge and flat unfinnished surfaces on C18th furniture in general will show evidence of a curved plane iron.