Chisel Shape Question

[Joe S]

Some gouges, when received from the manufacturer, have a more or less convex cutting edge and a single bevel.  My understanding of how most people sharpen their gouges is that they keep the convex cutting edge, but they add a slight second bevel or “heel” to the convex surface, and maintain a flat surface on the concave side of the gouge.  Similarly, a slight heel is added to straight chisels, while maintaining a flat back side.

The Manual of Traditional Woodcarving (1911) offers a very different perspective on chisel shaping.  From page 49:  “When the tools arrive from the manufacturer, their ends or cutting edges ….are quite long in the point.   The tool blades require grinding down to a fine edge, and this edge should lie in a plane not exceeding a right angle to the direction of the blade.” 

“If a carving tool is long in the point, this part begins to cut the wood first, before the rest of the tool has begun to cut the surface of the wood. Consequently chip which comes out is pushed rather than cut out the result being rough surfaces to the cut, and torn edges.  The tools should always be made so that they cut the surface first.  That part of the tool which lies below the surface should follow, not precede, the upper part of the tool....In grinding the tools, first grind the edges quite square…”

From page 52: “The edges of all tools except skew tools should quite straight and square with the direction of the blade.”

The author grinds a double bevel on the cutting edge, but also recommends grinding the edge from both sides (page 50):  “…the cutting edge of the tool is situated nearer the center of the carving tools…This applies to all the carving tools …”  From the drawings, it looks like he places the center of the cutting edge about 30% of the way in from the back surface that we would normally leave flat.

His rational for having a square cutting edge make sense to me.  It also seems to offer an advantage if a gouge is being used to stab in a cut.  With a square edge, you would have to do less rolling of the tool to get the whole length of the curve to cut, and it would also be easier to maintain a uniform cutting depth.

Any thoughts on this method of chisel shaping?  Does anyone sharpen their chisels this way?

[Dave B]

I have listen to Wallace Gusler as well as John Bivins talk about the verture of a nosed gouge. The middle of the tool being round out more than the sides. The advantage being that as you stab down into the wood it leaves the edges of the cut scalloped and will help prevent break out as the tool swings through the valute. I know that there are professional carvers that shake their heads at those of us that use rounded over gouges.

[Jim Kibler]

In practice for longrifle carving, square or slightly swept back and rounded will work fine most of the time.  For a very tight radised veiner or v-tool having the cutting edge radically swept back might cause a little trouble with the top edges of the wood not being cut, but rather split.  In longrifle carving, generally the modeling cuts are light enough that the shape is very forgiving.  For stabbing in there are virtues to an edge square to the axis of the tool and benefits to a rounded nose.  The rounded nose is more forgiving in adapting to contours, but fails in completely cutting at the edge when the outline is stopped (ex, where the edge being cut intersects another element).

[Joe S]

Well Jim, there’s a clear solution to the problem.  Just have full set of tools with square ends, and another set with a radius.  Like I needed another excuse to buy more tools….

[Jim Kibler]

The problem I've found with having a bunch of tools is keeping them all sharp

[Jay Close]

I had my first carving instruction from a fellow that was a student of a Greek master carver. Subsequently, I took a class with John Bivins specifically on longrifle carving and I have collected all the  old carving books I can get my hands on and studied each. Among all of this certain controversies emerge that seem to cause points of discussion/debate whenever carvers meet. The presence and extent of the internal bevel is one such debate.

 I was initially taught to keep the factory provided sweep as much as possible. This makes sense for modern tools and for the low relief of longrifle carving. However, when I was in the employ of the Colonial Williamsburg Foundation I had the opportunity to examine some gouges attributed to 18th c. manufacture. They were far from cleanly ground on their interior surfaces and showed many peen or fuller marks. A significant internal bevel would be a necessity to make them functional. I suspect that Sheffield carving tool chart with all the various sweeps neatly organized is a 19th c. development.

The "fingernail" grind is another point of debate. I have concluded that the basic or standard gouge shape should be straight across. This provides a flexible, general purpose edge. Fingernail forms or their opposite -- forward leaning "wings" on the corners of a gouge or V-tool -- are more specialized. You can do without them, but they are useful at times. 

One of the uses of a fingernail edge form is that you can walk it around an unusual curve if you don't have a gouge sweep to exactly conform to a layout line. Several years ago Ike Bay and Jack Brooks collaborated on a bit of an experiment using nothing but flat chisels round with radiused edges to do some simple rifle-style carving. I think the experiment was moderately successful and written up somewhere I don't recall. It did reinforce the utility of the fingernail edge shape but perhaps not to the exclusion of the "standard" grind.

My bottom line for what it's worth: sharpen most tools straight across, this is your baseline. Pick one or two medium deep gouges for a fingernail shape to experiment with. Use an internal bevel if you want, but I don't think you'll find in all that necessary or useful specifically for gunwork especially if you are using tools of modern make.

[Dphariss]

Some gouges, when received from the manufacturer, have a more or less convex cutting edge and a single bevel.  My understanding of how most people sharpen their gouges is that they keep the convex cutting edge, but they add a slight second bevel or “heel” to the convex surface, and maintain a flat surface on the concave side of the gouge.  Similarly, a slight heel is added to straight chisels, while maintaining a flat back side.

The Manual of Traditional Woodcarving (1911) offers a very different perspective on chisel shaping.  From page 49:  “When the tools arrive from the manufacturer, their ends or cutting edges ….are quite long in the point.   The tool blades require grinding down to a fine edge, and this edge should lie in a plane not exceeding a right angle to the direction of the blade.” 

“If a carving tool is long in the point, this part begins to cut the wood first, before the rest of the tool has begun to cut the surface of the wood. Consequently chip which comes out is pushed rather than cut out the result being rough surfaces to the cut, and torn edges.  The tools should always be made so that they cut the surface first.  That part of the tool which lies below the surface should follow, not precede, the upper part of the tool....In grinding the tools, first grind the edges quite square…”

From page 52: “The edges of all tools except skew tools should quite straight and square with the direction of the blade.”

The author grinds a double bevel on the cutting edge, but also recommends grinding the edge from both sides (page 50):  “…the cutting edge of the tool is situated nearer the center of the carving tools…This applies to all the carving tools …”  From the drawings, it looks like he places the center of the cutting edge about 30% of the way in from the back surface that we would normally leave flat.

His rational for having a square cutting edge make sense to me.  It also seems to offer an advantage if a gouge is being used to stab in a cut.  With a square edge, you would have to do less rolling of the tool to get the whole length of the curve to cut, and it would also be easier to maintain a uniform cutting depth.

Any thoughts on this method of chisel shaping?  Does anyone sharpen their chisels this way?

Wallace Gusler's carving video has an excellent segment on sharpening techniques.
The short edge at a different angle from the initial grind is what allows better control of the cut. Its used just like the heal on a graver.
Dan

[Curtis]

Joe S,

I am so glad you asked these questions, it couldn't have come at a better time.  I recently acquired a copy of The Manual of Traditional Woodcarving and was having many of the same questions myself.

Curtis

[Dr. Tim-Boone]

The fellow who teaches sharpening at Dixon's every year just outside of the gun shop showed me how ...if you have a couple of extra V tools you can cut one so that the toe follows the top and one so the top follows the toe..... that is one is tapered forward to the toe and one is tapered back from the toe. used them for cutting curves in incised carving lines ....  I haven't found it uncomfortable to use them as purchased, so I can't say whether his idea would help me or not.

[D. Taylor Sapergia]

I have a long narrow flat chisel (about 1/8" wide) that I use to remove the wood from the bottom of an inlay inlet.  It is sharpened with a bit of an arc, and I love the way it pares the wood away without digging in.  It gives me a lot of control.