A few months ago, we caught up with our friend Greg, the skilled woodworker deeply involved in testing and reviewing cutting-edge woodworking tools. Our conversation steered toward the condition of his hand tools, leading me to offer sharpening assistance for one of his chisels. Naturally, I ended up with a challenging one. I took before and after pictures to showcase the transformation.
The success of this trial prompted Greg to send me a stack of chisels, plane blades, carbide-tipped router bits, and even a kitchen knife for sharpening. While the chisels and planes posed some work but were manageable, the real test lay in the router bits. Sharpening carbide bits requires diamond tools, fortunately, I had Jende Diamond Films on hand. These films excel at refreshing and conditioning bits, though they can’t repair chips. Router bits, in most cases, are tough to fix once chipped due to their required balance and precise dimensions.
Below, microscope images taken with a Veho 400 microscope illustrate the edge of a dovetail router bit I received from Greg. The initial edge displayed roughness and wavering, typical of a used tool. Despite having coarse Jende Diamond Films starting from 80 microns (180 grit), I began with a 30 micron (500 grit) film and ended with a 15 micron (1,000 grit) film. To work effectively on the small bit, I crafted a slip stone using a 1/2″ wide piece of aluminum and 6″ PSA-backed film.
Following the contours and angles of the bit, the 30 micron film made a significant impact, refining the scratches on the bit’s surface and giving a crisper edge with minimal chipping. Moving to the 15 micron film provided a smoother finish, maintaining the edge’s integrity over time.
The Jende Diamond Films proved their prowess with carbide bits, reviving their edges for extended use. Transitioning to a wide radius Cove bit involved a similar process but with adjustments due to its rounded shape. Despite the challenges of the curved surface and slight hollow ground of the carbide bits, the 30 micron film, followed by the 15 micron film, eventually delivered excellent results.
In summary, the versatility of Jende Diamond Films as slip stones across various grits, ranging from 80 microns (180 grit) to 0.5 micron (30,000 grit), is truly remarkable. Their effectiveness in handling carbide bits and rejuvenating edges demonstrates their exceptional utility in woodworking.
Here’s the final outcome of the sharpened bit
