First time using card scrapper - lower my expectations or...

[John C Cox]

Each response seems to be a bit different...makes it even more confusing to the OP.

Too many versions to just flip a coin, and try one over the other.....about normal for sharpening threads around here...

Steven,

Here's what it boils down to in my experience......

If you need a scraper to deal with nasty grain and clean up the surface between Planing and sanding - get out the fine cut file and screwdriver. That's what you need. This makes a fairly large burr that cuts aggressively. Every time it gets dull - give is a quick couple passes on the file and off you go. It will leave fine tracks and slight lines... It's not really good as a final finish for show faces....

If you want to scrape instead of sand as a final finish.... Get out the stones and hone the scraper to form a very fine burr. Use a proper smooth burnisher to form and polish the burr. These do not cut aggressively - but they leave a buttery smooth finish that glistens...

Hope this helps.

[Patrick Chase]

But, The question still lingers.......

No matter how you prepare and use your scraper is surface left behind finish ready?

Yes, but only with a perfectly prepared scraper, and not for very long. If the burr is uniform and well-shaped, and if I can lightly run my fingernail down its tip/edge without any catching then it will take a clean shaving without tracking. I can still get a higher-sheen surface from my planes, though.

+1 to Derek's comments about angle. I would add that a lot depends on how large of a burr you're trying to create, and whether you "draw" the scraper's surface with flat strokes before turning the burr. If like Hock you just turn the Burr from a square corner then you have to use a relatively high angle as he did to get a reasonably-sized burr. If you "draw" the surface first then that gives you some extra material to work with at the very tip, which allows you to turn a smaller angle and still have a decently sized burr.

My own philosophy these days is to minimize how much I "touch" the scraper's edge, because IMO every manipulation is just another chance to mess it up and leave tracks on my work. I therefore *don't* draw the burr, and I turn at a higher angle (10-15 deg).

The smoothness of the burnisher is also an oft-neglected variable. My own Crown burnisher was too soft and got nicked up, and those nicks left defects in the burr leading to tracks. I have a steel Pfeil burnisher that seems quite hard and works well, and I also have a piece of solid 1/4" Tungsten Carbide rod (from McMaster Carr) that works well. Some people swear by the Arno Carbide scrapers as well.

[Jebediah Eckert]

Thanks Patrick!

[Steve Hubbard]

+1 on Glenn's advice to add a liitle oil, or WD-40, to the burnisher. That made a big difference for me.

[Derek Cohen]

If you use polished carbide, then lubrication appears unnecessary. The polished carbide "floats" smoothly over the carbon steel.

Regards from Perth

Derek

[Patrick Chase]

If you use polished carbide, then lubrication appears unnecessary. The polished carbide "floats" smoothly over the carbon steel.

Carbide burnishers are more or less immune to galling.

I still lubricate very lightly, mostly out of habit, but I don't think I really need to with the WC bar that I now use for most burnishing.

[Philipp Jaindl]

Sharpening a scraper so far has been more of a gamble then anything else for me, sometimes i get fantastic results others not so much. I never thought about lubricating the burnisher i'm gonna give that a try, also Hocks Video does help, seems like i tilted over the burnisher a bit too far and used too much force sometimes.

One question i do have is once it gets dull(er) are you going straight back to filing or can you "re-burnish", for lack of a better term, an existing hook?

[Derek Cohen]

Philipp, I joint the edge of the plate after a 3-4 "sharpenings" (what does one call the process of turning a hook?). It becomes evident how many times you can do so since the steel will stop scraping. The hook becomes progressively weaker and cannot be turned back. Then it is time to joint the edge flat and square, draw out the steel once again, and turn another hook.

Regards from Perth

Derek

[Patrick Chase]

Philipp, I joint the edge of the plate after a 3-4 "sharpenings" (what does one call the process of turning a hook?). It becomes evident how many times you can do so since the steel will stop scraping. The hook becomes progressively weaker and cannot be turned back. Then it is time to joint the edge flat and square, draw out the steel once again, and turn another hook.

Every time you manipulate the edge you create fractures that can expand into chips or other discontinuities. For me the limiter to re-burnishing is when the tip of the hook is no longer a perfectly continuous and uniform edge, such that I feel variations in "drag" when I draw my fingernail down its length. When that happens it's time to joint the edge and start over.

I seldom get more than 2 burr-turnings between jointings. By that point I can almost always still create a reasonable-looking burr, but it doesn't pass the uniformity test and will leave tracks on the work.

[steven c newman]

All too complicated for me......I just cut a new edge on a piece of glass and go back to work....maybe a bit of kerosene on the glass cutter...

Cut but cut to the profile of any molding. Edge gets dull? cut a new edge. Price? Go to about any Glass place and ask for their scrap barrel..Or, IF the neighborhood brat breaks another window...save the pieces.

Sometimes known as "Glass-papering" Have used this for quite a few decades. It also works to shape a hammer's handle, for a better fit..BTDT.

[Patrick Chase]

Sharpening a scraper so far has been more of a gamble then anything else for me, sometimes i get fantastic results others not so much. I never thought about lubricating the burnisher i'm gonna give that a try, also Hocks Video does help, seems like i tilted over the burnisher a bit too far and used too much force sometimes.

What are you using for a burnisher?

If it's made of steel and on the soft side (like my old unlamented Crown) and if you haven't been lubricating then it's likely that the burnisher itself has been damaged due to galling. If so then you'll want to get a new one, because it won't draw a clean burr even with lubrication.

Burnishers don't have to be expensive. My current burnisher of choice is a 1/4" polished Tungsten Carbide rod bought at an industrial supply house (McMaster-Carr here in the US). I think I paid $20.

[John C Cox]

Sharpening a scraper so far has been more of a gamble then anything else for me, sometimes i get fantastic results others not so much. I never thought about lubricating the burnisher i'm gonna give that a try, also Hocks Video does help, seems like i tilted over the burnisher a bit too far and used too much force sometimes.

One question i do have is once it gets dull(er) are you going straight back to filing or can you "re-burnish", for lack of a better term, an existing hook?

Philipp,

The easiest and fastest thing to do is to clamp your fine file in a vise and give the scraper 2 passes on each side... Back on the wood without even burnishing. As soon as it dulls - flip it to another edge. Once all 4 edges are dull - back to the file which is still clamped in your vise.. You will be back on the wood in 60 seconds... It's not a final finish sort of operation - but you will get the hang of it quick. And once you get the hang of it - you can fool with burnishers, hook angles and all that... But it's not necessary..

[Derek Cohen]

Building on John's comment about draw filing an edge, one of my favourite scrapers is simply prepared with a bench grinder wheel.

I made the following out of the end of a 3/16" thick O1 plane blade. It must be flat (as above).


Take it to the grinder (mine uses a 180 grit CBN wheel) and create a hollow around the edge.





It is almost effortless ...

Regards from Perth

Derek

[Patrick Chase]

The easiest and fastest thing to do is to clamp your fine file in a vise and give the scraper 2 passes on each side... Back on the wood without even burnishing. As soon as it dulls - flip it to another edge. Once all 4 edges are dull - back to the file which is still clamped in your vise.. You will be back on the wood in 60 seconds... It's not a final finish sort of operation - but you will get the hang of it quick. And once you get the hang of it - you can fool with burnishers, hook angles and all that... But it's not necessary..

This is probably a good point to note that scrapers have a multitude of applications within woodworking, with different demands in terms of preparation etc.

Most of what I've said in previous posts in this thread assumed that you're doing final smoothing and trying for a finish-ready surface. If you're not then you can be a lot less OCD about it than I've implied, turn the burr more times from a single jointing, etc.