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Introduction to the Skew


No surface finish from any other tool can compare with that produced by a skew that is properly sharpened and skillfully applied.  However, no other tool has such a reputation for being as difficult to handle as the skew, sometimes called a skew chisel.   


One of the more familiar applications of the skew is that of making a planing cut on a spindle, but there are many others such as making V cuts and incising the fine detail on a finial.  Often, the point of a skew is the only tool that will reach into a narrow slot to make a fine cut at the bottom.

 

Types of skews.  The body of the traditional skew is rectangular in cross section.  A more recent development is a skew whose cross section is an oval.  Favored by some but not all, the oval cross section makes it easier to rotate the tool to a given angle on the tool rest.  Detractors say the oval confuses the issue because there is no flat surface to provide a reference point, and the oval makes it harder to sharpen.  


A compromise between the rectangular and oval cross sections is the body with rolled-edges.  The cross section is basically rectangular, but the corners are rounded so the tool can be rotated on the tool rest without digging in.  


Yet another version are those having a circular cross section, the so-called round skews.  These are intended for small work and are available in diameters of 1/4, 3/8, and 1/2”.   


The cutting edge of a skew has a double bevel that may be either straight or curved (radiused).  The ends of the cutting edge are the heel and toe.  The toe is also called the long point.  The length of the bevel is normally about 1.5 times the thickness of the body.  This produces an angle between the bevels of about 35 to 40º, which is small enough to allow the edge to be brought to razor sharpness with a little work.


When things go wrong with a skew, the result is likely to be either a catch or a runback.  A catch is where the cutting edge digs into the wood, probably taking a large divot.  In a runback the tool grabs the surface (or so it seems) and then takes off in the opposite direction, carving a deep track as it goes.  Both are caused by presenting the tool to the wood at the wrong angle, and both are avoidable.  


Planing Cut on a Spindle  


Be sure your skew is properly sharpened before you begin using it, and in particular, be sure the bevels are flat.  See the article on sharpening a skew.  


Mount a spindle blank on the lathe and true it up.  Keep the blank on the small side, maybe 6” long and not over 1.5” in diameter. Plan to run the lathe slowly at first.  Suggested RPMs are given below.   


The tool rest will need to be set a bit higher than for a gouge.  It should be set so the cutting action occurs somewhat above the 10 o’clock position on the spindle when the handle of the tool is tilted about 8º.  What this means is that the end of the handle should be about 2” lower than the cutting edge for a tool 18” long, overall.


Start the lathe and then use a pencil to mark a line around the piece near the middle.  Then turn the lathe Off.  


With the lathe Off, lay the skew across the tool rest with the cutting edge facing to the left.  Press the bevel flat against the wood and adjust the position of the handle so that the cutting edge makes an angle of about 30º to the pencil line. Position the tool so the cutting will take place on the lower half of the cutting edge.  


Adjust the height of the tool rest, if necessary, so the handle tilts down a bit and feels comfortable and stable with the bevel flat against the wood.    


Now rotate the lathe by hand and see what happens.  You may get a tiny shaving, or you may not.  If you don’t, rotate the tool counterclockwise ever so slightly to roll the cutting edge into contact with the wood.  As you do this, you will have to raise the handle a small amount to keep the bevel flat against the surface. The shaving should now appear.  Note how little you have to roll the tool and lift the handle to get the shaving. Remember this.


The width of the shaving is controlled by swinging the handle left or right.  The depth of the cut, or the thickness of the shaving, is controlled by rotating the tool. Verify this by turning the lathe by hand and observing the shaving as you make small changes in the orientation of the tool.  


Also note that when the edge engages and begins cutting, the wood tends to push the tool back out of the cut.  The force is small, but it is there.  Be prepared for it.


Try it under power.  Set your lathe for its lowest RPM, then start the lathe.  Position the tool against the wood as described above, but be sure the back edge of the bevel makes the first contact.  If you do this, the cutting edge will not engage before you have a chance to get the bevel planted against the wood.  


After making sure the impending cut will occur on the lower half of the cutting edge, roll the tool (and lift the handle) until the edge begins to cut, then advance the tool slowly in the direction of the cut.   


With the lathe turning slowly, you will not be able to advance the cut very rapidly.  After you build a bit of confidence, speed the lathe up to around 1,000 RPM.  This is still slow but it will get you closer to what most turners recommend.  


I use a palm-up grip with my index finger against the tool rest and my thumb pressing the tool against the tool rest.  Some turners suggest a palm-down grip, but I can’t feel the action of the tool nearly as well with my palm down.  The force on the cutting edge is a combination of sideways and down, so the tip of the tool is not going to tend to fly upward.  Nevertheless, keep a grip on the handle with your other hand, but don’t overdo it.


There’s little reason to be afraid of the procedure described above. With the small spindle turning at only 1,000 RPM, it will not contain enough energy to be dangerous.  Even in the worst case where you get a dig in and jerk it off the lathe, it won’t be going anywhere fast.  It may bounce off your faceshield and drop to the floor, but no damage will be done.  The greater injury will be to your pride.  


Problems?  I can’t imagine that anything might go wrong, but just in case . . .  


Runback, possible causes:  Failure to keep the bevel flat on the surface; rolling the cutting edge too far toward the wood; lifting the handle too much so that it comes off the tool rest.  Not applying enough force to the tool to counteract its natural tendency to back away from the cut.  Letting the cut get onto the top half of the cutting edge where it’s more difficult to control.


Dig in: You made a big boo boo.  Did you let the long point contact the wood?  That will do it, as well as approaching the work with the handle too much straight-on to the work and not rubbing the bevel.  The handle must be well to the right with the cut high on the workpiece, near 10 o’clock, or even higher.


The cut tends to get deeper and deeper:  Roll the cutting edge away from the wood, lowering the handle as you do.  This is just the opposite of what you do to begin the cut.  


The shaving is too wide:  The handle needs to be farther to the right, or, you’re rolling the edge too far into the wood.


Hard to control; leaves a rough surface:  The bevel is concave instead of being flat, which is a sharpening issue.  What happens is that the cutting edge tends to curve into the wood and take a deeper cut as it progresses.  The only way to prevent this is to forcibly lever it back out using the heel of the bevel as the fulcrum (pivot point) of the lever.  The wood fibers are pried away rather than being cut.


Runs back just as the cutting edge engages:  Either you are being ham handed in rolling the edge into the wood, or the bevel is rounded over (convex) right at the cutting edge.  This is another sharpening issue.  


Change direction and repeat.  Once you’ve gotten pretty good at doing the right-to-left planing cut, swap everything around and try it in the other direction.  However, don’t just jump into it; take it one step at a time.  With the lathe Off, establish the tool position, rotate the lathe by hand, and so forth, as you did initially.  


Whether you should swap hands (so your right hand rides on the tool rest) depends on what is most comfortable for you. If you can position and control the tool without doing the swap, it’s OK to go that way.  However, it is good to cultivate the ability to operate all turning tools either-handed.  


Working near the ends.  Because a planing cut begins somewhere in the middle of a spindle and then advances toward one end or the other, there is a region near the end that is behind the cut and which doesn’t get the benefit of it.  The obvious remedy is to make a subsequent cut in the other direction.


Practically speaking, you can’t initiate a cut at the very end because there’s nothing for the bevel to rub against.  However, you can cut from the other direction and actually run off the end, uneventfully, as long as you don’t go far enough to drop the bevel off the piece.


This gives us something else to practice.  Make a planing cut that begins near the tailstock end of the spindle and advances to the left.  Then, come back and make an overlapping cut that advances to the right.  The objective is to pick up the second cut in such a manner that you can’t tell that two different cuts were made – a seamless overlap.


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