Turning with Sharp Tools - Roughing Gouges
Last month, we continued our series of tutorials which are covering the proper sharpening of lathe tools. This month, we're going to explain the proper method for sharpening roughing gouges. Next month, we will cover the bowl gouge.
Special Note Concerning Roughing Gouges -
We wanted to take a moment before we get started with this article to remind our customers not to use the roughing gouge for face plate work (i.e. face grain bowls and platters). We get lots of questions and comments from customers who are using this tool for this type of work, and wanted to remind everyone: this tool is not suited for this type of work, and can be very, very dangerous! These tools are designed for spindle work, and using them for face grain blanks can result in breakage of the tool or the piece being worked on. Nobody wants flying chunks of metal or wood zooming through their workshop...so be safe and use this tool for its intended use only!
When to Sharpen -
Sharpening should be performed when the tool no longer can produce ribbons of material during cutting. Other signs of a dull roughing gouge - a tendency to want to bounce excessively when rounding spindles and/or difficulty in running the tool down the face of an already trued up spindle (for example, the tool may collect shavings on the cutting edge which pauses the cutting action, or excessive pressure is needed to move the tool along its cutting path)
Correct Sharpening Angle -
The bevel should be sharpened at a 40 degree to 50 degree angle, with 45 degrees being the best all-purpose angle for sharpening. Reducing the angle to 40 degrees will aid in cutting softer woods clearly, and increasing the angle will aid in cutting harder or more highly figured woods. The tool's front edge should be ground straight across, without any unevenness or grinding back of the top edge of the tool (also known as the "ears" of the gouge).
Grinding Methods for Roughing Gouges -
Sharpening with a Grinding Wheel
Once the proper grinding angle has been set for the rest on the grinder, begin by laying the heel of the bevel (the back side of the cutting edge) against the stone, then slowly rotate the cutting edge to make contact of the wheel. To properly grind the edge, the tool must be steadily held perpendicular to the face of the grinding wheel. Rotate the handle of the tool slowly, steadily, and smoothly back and forth to grind the entire edge. Be careful not to pause while performing the grinding motion, as this will cause misshaping of the front face of the tool. A properly ground tool should be perfectly flat across its top edge when viewed from the top. Any uneven spots will affect the tools ability to cut properly, especially when the tool is being rotated during the cutting process.