WWA Info Exchange :: View topic - Sharpening a card scraper Page 1 of 5
We start by clamping the card in the vise, with about an 1 1/4" showing. We then commense with DRAW FILING, which is pulling the mill file along the edge, while holding it perpendicular to edge. I like to clamp the card just high enough that my knuckles barely touch the top of the vise. This helps me keep the file square to the work. I guess that makes me a knuckle dragger.
This will raise a ragged burr on the edge of the scraper that needs to be removed by dressing the edge. To do this, I lay the file flat on the surface and with gentle pressure, dress the edge take care to maintain the square edge.
NOTE: Some poor, ignorant souls will stop at the burr raised by draw filing, and say that the scraper is sharp. To that argument, I counter that you wouldn't even consider sharpening your Leigh-Nielssen plane blade with just a file, so think about the quality of the edge you're trying to achieve.
The next step is to hone the edge, repeating the motions of the file, with a hard Arkansas stone.
mhtml:file://C:\Users\Ed\Documents\Wood related\WWA Info Exchange View topic - Sharpening a card scrap... 7/24/2010
Then dress the edge in the same way.
Next, comes raising the burr. To do this we need a long hard burnisher. I prefer a round one as it is far more forgiving to use, than an oval or triangular cross section.
Yes I know, some neanderthals will insist that you can use a screw driver, or a nail or the extension from a socket set. I'm not going to spend anytime on this argument other than to remind you that you are trying to produce a edge of the same quality at you would on your best planes or paring chisels.
To raise the burr, lay the card flat on the bench, an with between 1o-3o of bevel (exaggerated in the photo), stroke the edge with gentle pressure. 3-5 strokes are plenty. Use a drop of oil on the burnisher to prevent galling.
Then the burr needs to be pulled perpendicular to the surface. To do this, clamp it back in the vise, and draw the burnisher at 90o to the edge, just as in draw filing.
Next, we turn the hook. To do this, hold the burnisher at a constant angle, and gently draw it across the edge. The angle can be anything between 5o and 15o, depending on personal preference. I like something around 8o. The important thing is to keep it constant, and as with raising the burr, the fewer strokes, the better.
An alternative to the long burnisher, is the adjustable burnishing tool, like the one sold by Lee Valley (mine is wood, but I think the new ones are plastic). A drop of oil, and adjusted to 8o; it's good to go.
Just a reminder, there are four usable edges on the card, and they tend to all look alike so I like to label them with a marker.
Lastly, you now have a scraper with four sharp edges, BE CAREFUL!! It's very easy to cut yourself if you're not paying attention.
Next time out, try a scraper, you'll wonder how you ever did without one.
Tom
_________________
"There is no path to peace, peace is the path." Mohandas K. Ghandi
mhtml:file://C:\Users\Ed\Documents\Wood related\WWA Info Exchange View topic - Sharpening a card scrap... 7/24/2010
_________________
"There is no path to peace, peace is the path."
Mohandas K. Ghandi