V tool Geometry

[Tom McMahon]

In a previous post I mentioned that, in my opinion, Pfeil,or most other new, V chisels are not ready to use as purchased. In this post Iwill try to explain my thinking about V chisels.
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In this picture we see a Pfeil V tool as purchased, the redarrow pointing at the keel on the bottom of the tool.
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This picture shows the bottom view of a Pfeil as sold and anAddis prepared for use. The keel of the Addis is sharpened to a near knifeedge, this allows the keel to get down into the cut and slide along withoutdigging in or rising up out of the cut, but you can dig in or rise out of thecut by raising or lowering the handle. With the wide keel the cutting edge is alwaystrying to dig in and is much harder to control because you can’t get the keelinto the cut to ride the bevel. The cutting edge needs to cut enough clearancefor the rest of the tool to move in the cut behind it. This is old hat for many but may help some beginners prepare and use the V tool.

[Ted Reischl]

I would not be so quick to state that Pfeil is not grinding their tools correctly.

Below is the grind on a Pfeil V tool.

The top portion of the drawing shows the tool in a top/front and side view.

The lower portion shows the tool elevated into cutting position, 20 degrees.

Notice the two red dots on the bevels. That is what rubs on the cut wood and causes the tool to want to climb out of the cut.

Note that the keel is not interfering with uncut wood as are the bevels.

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I recently watched a video produced by a master carver in which he pontificated at length about fixing the keel on a V tool. He may be a master carver but that does not make him a tool engineer.

The important thing to note about the drawing above is that the bevels present less surface as the tool handle is elevated to steeper degrees. I have watched several "master" carvers who would elevate the tool fairly steeply and then use the other hand near the cutting edge to push it. Makes sense, as the tool handle elevates it becomes virtually impossible to move the tip forward. By pushing on the lower end the force is directed along the cut.

BTW, just cause a company grinds a tool differently does not make them correct. IMHO, someone at Addis has bought into the myth about the keels on V tools. Or, their geometry may be somewhat different which calls for them to grind that sharp corner.

In cannel gouges solve the problem, but they are a devil to sharpen. A V in cannel would be extremely difficult at best.

The same issue exists with U type gouges, the bevels ride on the cut material forcing the tool upwards.