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Skews Part 2

Incising a Line, End Grain, V Grooves, and More


Incising a line.  Suppose we want to cut a rectangular groove in a spindle. The obvious tool to use is a diamond parting tool in a peeling cut, but the problem is that the wood will often tear out and leave ragged corners.  However, if we take the long point of a skew and cut a fine line at each edge of the groove, the problem will be solved.  


The line does not have to be very deep.  Once the cut with the parting tool is below the surface, the tear out is less likely to occur.


To cut a fine line, the skew is used with its long point down and the body of the tool at right angles to the lathe.  The cutting edge must be exactly in line with the movement of the wood past the point so there is no tendency for it to skate sideways.  Once the tool is in position, simply arc the point into the wood to produce the line.


Because little if any wood is removed, you can cut the line only to a depth of about 1/32” or 1 mm.  The wood is simply compressed at each side of the V-shaped incision, and you will quickly reach the limit.  


This straight-on approach to the wood produces a line whose side walls are not perpendicular to the surface.  To get a perpendicular side wall, you must swing the handle to the side, as described in the next section.  


Making a cross-grain cut on a spindle.  The skew excels at cross-grain cuts and leaves a better surface than any other tool. The task may be as mundane as squaring up the shoulder of a tenon, or it may be cutting the fine details on a finial or an icicle for a tree ornament.  As before, it is used with the long point down.


The key to success is placing the plane of the bevel parallel to the face of the surface being cut.  This requires swinging the body of the skew to the side an amount roughly equal to one-half the bevel angle.  This places the plane of the bevel parallel to the plane of the impending cut so that the bevel will lay flat on the newly-cut surface as the cut advances.


After the tool is properly aligned, and with the handle slightly down, initiate the cut by lifting the handle just enough to arc the point into the wood.  Then, depending upon the extent of the cut, you may need to push the tool forward.  Do not raise the handle so much that the cut goes below center.


You must take only a very light cut so that the wood peels away as a shaving, which may take the form of a whirling cone.  A cut that’s too heavy will require considerable force to advance the tool, and this, with a possible vibration, is a clear indication that you should be taking a lighter cut.   


Making a V cut.  First of all, you don’t make the V all at one time with one or two deft strokes.  Rather, the V is developed by a series of small cuts, alternating from one side to the other, so that it gradually approaches the full profile.  


The reason for this is that you must remove the wood from the V. This seems like an obvious point, but the initial cut will not release the wood; it takes the opposing cut from the other side to actually cut the wood free.  


For each cut, you must very carefully align the plane of the bevel with the direction of the cut you’re about to make.  This will require swinging the handle to the side, as is done in making a cross-grain cut, but the amount of the swing will be somewhat less because of the angle of the sides of the V.  


Therefore, making a V cut takes a lot of aligning and a lot of swinging as you switch back and forth from one side to the other. However, after a little practice, your speed will increase as the procedure becomes automatic – it’s a muscle-memory thing, whatever that is.  But at first, you’d better take your time.  


Cutting a convex curve.  The essence of this cut is rolling the skew over the curve while keeping everything under control.  A bit too much rolling into the curve, and you will get a runback.  My suggestion is to creep up on it; start with a simple planing cut and let it develop into a convex curve.  


Mount a practice spindle 6 or 8” long between centers.  True it up. Then cut a groove about 3/8” wide and 3/8” deep somewhere in the middle.  This groove will provide a convenient place to stop the cut.  


Begin a planing cut an inch or so to the right of the groove, and cut toward the groove.  Keep the cutting action in the lower half of the cutting edge.  Adjust the swing of the handle so the wood approaches the cutting edge at about a 30º angle.  Take a light cut, and carry it all the way to the groove, just because you can.  


On the next cut, when you get to within about half an inch of the groove, roll the cutting edge into the work (and lift the handle) ever so slightly so that the cut gets gradually deeper as you approach the groove.  Then stop the lathe and examine the surface.  You should see a very slight convex curve where you rolled the tool.


Try it again, but this time, start rolling into the curve a bit sooner, perhaps 3/4” from the groove.  Don’t let the tool back away from the cut; keep it pushed forward to ensure the cutting takes place in the lower half of the cutting edge, not far from the short point. This should result in a curve that is more pronounced.


As the curve develops, you may find that you have to raise the handle considerably as you roll it into the curve, and also you may have to reduce the amount the handle is swung to the right.  Adjust the height of the tool rest if necessary.  Just keep the cut well above center on the workpiece, and in the lower half of the cutting edge on the tool.  


If things have gone well to this point, all you need now is practice. Just make progress rather slowly; don’t get too aggressive with the rolling or you will get a runback.  And, at some point, you will get a runback.  When you do, just grab your spindle roughing gouge, clean up the mess, and go at it again.  


There are two sides to every story.  What about the other side of the groove?  At some point, you should learn to make the cut in the opposite direction.  I’ll let you decide when you should do that.

The next step is to cut a convex curve that ends precisely at a predetermined point.  So, mount a practice spindle on the lathe and true it up.  Then use your skew to cut a shallow V groove near the middle of the piece. The bottom of the groove is your aiming point for the end of the curve.  


As you did before, begin a planing cut an inch or so to the right of the V groove.  As you approach the groove, roll the skew to form a curve, but don’t try to go all the way to the bottom of the V in one pass – unless the V is very shallow, of course.  The objective is to get a smooth curve that ends at the bottom of the V with no lines or tool marks left behind.  


There are two issues here.  One is getting a smooth curve without waves or flat spots.  The other is having it end exactly where you desire.  Chances are that quite a bit of practice will be needed before you will be able to do this with confidence.  Have fun!  






Detail work on a finial.  The following series of photos show how a skew may be used in making an icicle for a tree ornament (or a finial).  Other cuts are possible, but I have not shown cuts that can be made just as easily with a detail gouge.  The skew I use on small items like this has an oval cross section and is 3/4” wide.


The black walnut blank is about 1” in diameter and is mounted between a scroll chuck and the tail center. The first steps are to square the end of the blank, incise a line, and then form the tenon that will be used to attach the completed piece to the globe of an ornament.

xxx


A planing cut is then used to reduce the diameter of the blank a small amount and produce a clean surface at the very end.  The cutting edge will be advanced beyond the end of the blank a small amount.  Next, a spindle gouge is used to remove waste wood, and then the heel of the skew is used to form the convex surface of the base.

X

XX


The other side of the cove is then cut to shape.

X   

X


After reducing the diameter of the section to the left of the cusp, lines are cut to mark out the extent of the ball and to prevent tearout. The toe of the skew is then used to begin shaping the ball.

X      X      X


A gouge is used to shape the detail to the left of the ball because two of the surfaces are slightly concave.  A skew is not the best tool for cutting concave surfaces.  Then a lot of waste wood was removed.                                                                             X

                 X      


A small detail gouge was used to shape the stem because of the mildly concave curve.                                                          X     

 X   



After more shaping with a gouge, followed by sanding, the piece is ready to be parted off.  To part it off, I pull the tailstock back and then steady the piece with my left hand.  I use the long point of the skew to to cut it free.  Then after cleaning up the tip, it is done.



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