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I am unable to sharpen a card scraper despite trying many times. I am using a Crown card scraper and burnisher. Most times I start by filing the edges, followed by whetstone, and then on to the burnishing part.

I tried both with a hard as well as light pressure on the steel. Saw many YouTube videos, but don't have anyone in person to guide me. I just cannot manage to get a burr.

Can someone help me understand what I am doing wrong.

Graphus
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Shahid Thaika
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    Hi, welcome to Woodworking. For starters don't despair, you're not alone here..... many many people struggle to properly sharpen card scrapers when they start out. Long ago I posted a big Answer on scraping v. sanding that you might want to start with if you haven't seen it already, here's the link. If none of what I wrote there helps directly, can you tell us what you want to use scraping for — finished surfaces or just as a part of finishing, where you will also be sanding? – Graphus Jul 10 '21 at 08:03
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    The most likely cause of your difficulty may be very similar to one common in sharpening knives, where a failure to get a sharp edge is caused by preceding steps not going far enough. Since a burr happens virtually automatically when you draw a burnisher along an edge at almost any pressure if you're not able to get ANY burr it's possible you haven't created a 90° corner to draw the hook from. I think this is the #1 reason people struggle to achieve any burr. And #2 is the burnisher not being hard enough; if it's softer than the card (unlikely, but possible) it can't move the steel. – Graphus Jul 10 '21 at 08:15
  • Hi @Graphus, I am actually making a board bow, and need to remove wood to make the board bend, as a part of the tillering process. I currently use a block plane or a spokeshave, depending on how much wood there is to remove, and use a rasp at the corners (next to the handle), where the spokeshave can't reach. Using a card scraper would not only reach all parts of the surface to be scrapped, but it would also remove less and avoid digging too deep into the wood. – Shahid Thaika Jul 10 '21 at 18:04
  • I have to come clean though that I do not have a vice, so I don't have anything to hold the scrapper in place while filing and honing to get the 90 degree corner. I guess I need to do something about that first. – Shahid Thaika Jul 10 '21 at 18:05
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    Maybe you can clamp the card to something solid (tabletop? shelf?) to hold it steady for the 90... that's really important. – Aloysius Defenestrate Jul 10 '21 at 18:12
  • Well more good news is you don't absolutely need a vice to sharpen a card scraper. They are useful, but not essential — I sharpened my scrapers for years before I had a vice (although full disclosure, I wasn't using card scrapers much during this period {I was using a different type of scraper} but rest assured, you can definitely sharpen a scraper without a vice). I would however highly recommend getting a vice because I can virtually guarantee that once you do have one and get used to using it you'll wonder how you lived without it! :-) – Graphus Jul 10 '21 at 18:38
  • The most important step is to, before you burnish, inspect the edge with a lens, 5x minimum. You want this square to a sharp 90. Feel alone , or relying on a certain regimen of steps, doesn't suffice. – bpedit Jul 22 '21 at 17:37

1 Answers1

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Without seeing or handling a scraper that has gone through a sharpening process and isn't working it is hard to diagnose what's gone wrong, but there are some common problems that you might be experiencing.

If the user is unable to create any burr at all1 I believe the most common issue (and the one I think most likely to be the cause here) is the prior preparation of the edge hasn't achieved 90° corners for the hook to be drawn from2.

So first thing you should do is make sure you are creating square edges on your scraper to begin with. Then the creation of a burr you can work with3 is almost guaranteed.

There are various tricks to ensure you'll get the square edges you're after, and most rely on some kind of block of wood to help hold the card upright. Instead of trying to describe this further in words I'll just link to two videos I think give good clear (and, importantly, brief) demonstrations of how to do it.

The first is an older video from StumpyNubs, and as usual for him he explains what he's doing and why very well. 5 steps for easy woodworking card/cabinet scraper sharpening

The second is one of a couple of vids on scraper sharpening on Fine Woodworking's YT channel. This one, How to Sharpen a Card Scraper, has Mike Pekovich demonstrating a nice simple method with one neat trick (courtesy of Brian Boggs) that is not often seen elsewhere.

No vice
Now both of these do show a vice being used, but you can easily work around this until you have a vice as long as you have some decent clamps.

If you clamp a piece of wood with a known square edge to your bench/work surface and then clamp the card scraper to that you have in effect created the same workholding that a vice provides. It may be in a slightly clunky and slower way, but it works :-)

1 None can be seen or felt, and the scraper won't produce ANY shavings.

2 If instead of a sharp 90 you have a sight radius along your edges when you do the burnishing it just moves metal into the space above the curved edge and it either doesn't create a hook/burr at all, or it's very small and isn't projecting far enough to engage with the wood.

3 Note that as I mention in the old Answer I linked to in the Comments, there isn't just one size and style of burr that will work. All different methods that successfully create some sort of burr are being used by someone, just for different levels of work and/or in slightly different ways. Some users want a very noticeable, very aggressive burr because it suits what they're doing, others need a very tiny burr that produces the most wispy shavings which show that only the tiniest amount of wood is being removed.

Graphus
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