Card scrapers

[Mark Kelly]

Once you have tuned a card scraper, how long can I expect it to last before I have to retune it?

And, when retuning it, do I start from the beginning by making a flat surface before burnishing the bur?

[Tom Scott]

It's kind of hard for me to say how long a bur lasts. I will usually turn 4 burs at a time, and since I can't remember which one I used last, will rotate around until I find one that works. When they are all used up, will start from the beginning by jointing the edge and proceed through all of the steps again.

Tom

[Alan Turner]

Mark,
I get 5 or 6 hooks out of an edge before reflattening, etc. When you can no longer pull a shaving, burnish the edge towards the edge, and then reform it back to the blade, and you will be good to go again, in about 30 seconds. No need to file and hone each time, in my experience. When the re-burnishing no longer works, it is time to return to to the file and stone.
Alan

[Tim Sproul]

that's like asking how long an iron will stay sharp....too many variables for any definitive answer other than, "as long as it stays sharp." And I'd likely argue you'll get more variability in scrapers because there is the added step/variability of raising the burr, unlike sharpening an iron.

For retuning, I wip out the file and stone.....but I do know others who successfully raise the burr again without.

[Dave Anderson NH]

Since each scraper has at least 4 usale edges, when I get a new scraper or make one from scrap steel, I etch the numbers 1 to 4 near each cutting edge. After turning a new burr or renewing an older and dulled one, I start using edge #1 and proceed along to #4 after which it becomes time to rework the edges again. It's a real help in remembering and identifying which edge has been used. Heck, even magic marker would work for a while before it wore off.