Sharpening and using a scraper.
When I suggest that you should use a scraper in your woodworking. Some are going to say “What?” Others are going to say “I’ve tried it and it doesn’t work!” And maybe others are going to say “I use them every day!” To the latter I’d say “Get a life!” To the previous I’d say “Hang on and we’ll fix your problems!” And to the first I’d say:
Scrapers have been used in woodworking for a long time. It is believed that the earliest scrapers were made out of pieces of handsaw blades that had fulfilled their usefulness of sawing. Today we have many kinds of scrapers.
Not this kind
They are used for paint scraping. They are also useful for getting glue off board glue-ups. The carbide blade scrapes away the glue from the joint. Use them for that. They work.
Not this kind
They are used for scraping out seats in a chair. Getting rid of punk wood on that slab you are going to use for a table top. You can sharpen them on a grinding stone and put a lot of pressure as you make them work. They work, but they are not for finessing wood they are a rough cutting scraper. Others may quibble with that, and I’m OK. You can use a tire iron to work on a lathe, but that might not be the correct tool. But if it works for you, I’m not here to tell you to stop.
As I’ve said these are things I’ve learned, others might have had a different teacher. Or they learned their skills at the school of hard knocks.
This is the scraper that I’m talking about.
They come in different sizes, different shapes, and they come in different thicknesses.
They also have a different hardness in the metal structure. They are somewhere between soft (they wouldn’t have a very long life) and hard (be impossible to sharpen)
They will rust
If you leave sweat on them when you are finished and you just leave them on your bench.
First thing you want to do if you purchase a new shaper is (Open the package) LOL. What you want to do is get the edge flat. Clamp the scraper in a pair of wooden jaws in your vise and with a fine file go lightly down the edge to make it nice and flat. Look at it and make sure that there are no high spots.
Then I take the scraper and slide the edge over some 600 grit silicon carbide sandpaper. To keep a flat straight edge, bend the scraper with both hands, maybe a ¼” curve and then slide it down the sandpaper. It’s tough for me to hold it with both hands and take the picture. So this is a one handed bend and slide.
After you’ve done that a few times and the edge is nice and smooth, you want to remove any burr that might be on the edge. So now slide it on the edge across the same sandpaper.
Do that on both sides of one edge.
It might be good for me to tell you this bit of knowledge. DO NOT SHARPEN both edges of the scraper. You are going to be holding this with your dainty fingers and hands and you don’t want to be holding razor blades and squeezing them tight. Blood messes up woodworking projects.
Now you have both surfaces of one edge nice and smooth and no burrs. As you use a scraper you will have to periodically re-true it up by doing the above steps over and over again. That is not a one-time when I buy a scraper function.
Take the first finger of your right hand (Do it right now, I’ll wait) Take that finger and place it in the valley between your right ear and your head, just in behind your ear lobe. At that point on your body you have an over-abundance of oil. Slide your finger through that oil filled valley and then rub the same finger down the edge of the scraper. You have just lightly lubed the surface of the scraper so that your sharpening tool will slide easily. Notice you don’t need a quart of 10W-30 motor oil for this function. Ear oil is enough. I failed to mention there is another spot that contains the required amount of the aforementioned oil. That is the valley between your nose and your cheek. Not the little hole (were not using bugger material for lubrication). The spot where all of your pimples started when you were a teanager.
Place the scraper on the edge of your bench, table saw, kitchen counter, some place where you have a solid edge. Then use a screwdriver, engine valve stem, hardened steel rod, if you use a screwdriver get one that doesn’t have chrome plating on it. Just a nice hard shiny metal rod. Slide it across the edge, by drawing the shaft of the screwdriver toward you. You want maybe a 5 degree angle on the hardened steel rod. What you are trying to do is to slide a microscopic edge of metal toward you. On that nice smooth edge you just made you are now creating a razor sharp edge, which is sliding toward you. You should slide that hard steel rod back and forth a few times, continuing to pull the metal toward you. After you do this a few times you will know when to stop.
If you continue until the edge of the scraper looks like a knife edge, I can tell you this, “You have gone too far!” and “You have pressed too hard!”
Now you want to take the scraper and put it back in the nice wooden jaws of your vise. You want to take your hardened steel rod and bend that curl of metal you pulled to the front edge and curl it to the side.
I now will now show you some of my artistic ability, Not!
The top picture is placing the behind the ear oil on the scraper. The second picture is drawing the metal on the edge toward you. And the third picture is forming the curl unto the side of the scraper. You can put the curl on both sides of one edge. If one is not sharp then rotate it and use the other side. It is OK to sharpen like that, just don’t put it on the opposite side of the scraper. If you have 3 or 4 scrapers when you sit down to sharpen them it goes quite fast and you put off having to work with a dull scraper until you are really tired of it. Just grab another one and keep trying until you find a sharp edge.
The burr that you make is not the size that you see in the picture. It is quite small, but you can feel it and if you run your fingers down the edge, they will cut.
To use it hold the scraper in two hands, give it a slight bow, maybe 1/8” and with your thumbs in the middle, and your fingers on the outside push it down the board. What you will get is dust. What you are supposed to get is shavings.
You will notice the scraping dust on the board just above the scraper edge.
This occurs when you are not holding the scraper correctly. You will remember the burr that we turned on the edge of the scraper. What you want is those burrs to cut wood not scrape along the surface of the board. You held your hardened steel rod at about a 5 to 10 degree angle as you turned that burr. You now want that scraper to be held at about the same 5 – 10 degree angle. So it is almost straight up and down.
If you’ve tried this before and it didn’t work. It’s either the burr was not made correctly or you didn’t hold it correctly. That’s all there is. Nothing fancy. It makes a surface on the board that you can’t get with sandpaper. It’s glassy smooth. You can get rid of planer snipes and washboard surfaces. Hold the scraper at a 45 degree angle as you move down the board so you don’t follow in the valleys. You want to cut the tips off all of the high places.
You don’t want to be like a boat riding between waves in the ocean. You want to be like a pier that cuts across all of the waves.
A couple of other things. Single edge razor blades make great scrapers to remove paint and varnish runs. Let the finish dry and then just scrape the blade down the high spots to level the finish out with the rest of the finish. Hold the blade like you were taught to hold your scraper. Don’t cut the finish off, just scrape it away gently.
You can also buy holders for scrapers. They are handy it you are trying to scrape a log slab that you are making into a table because the scraper will get hot enough to be uncomfortable.
You use the center knob to put the curve into the scraper.
You hold it in both hands with your thumbs in the indentions and push. Again holding at the correct angle.
You can also buy jigs to help you file and sharpen your scrapers. I’ve got three different kinds.
Do it like I showed you here, that way no matter where you are you can sharpen a scraper. You won’t have to say, “If I had my jig I could sharpen it!”
You always Have your ear, or someone else’s. You can find a screwdriver. And you can get away without the sandpaper, but, it is better with it. You don’t need the jig to hold it, use your hands. You just might have to cut up a perfectly good handsaw to get your scraper material though. Too big to carry in your billfold, you might have to start carrying a gym bag though.
Updated next morning:
I noticed the picture of the sandpaper where I had been cleaning up the edge of the scraper after using the file. If you noticed that there were black marks in rows which meaned that this previously planed board had an uneaven surface. So this morning I thought I’d take a picture again after I’d done the practice scraping picture taking. Here is the new picture with the sandpaper from the earlier sanding.
There is still an uneaven surface but it is definetely smoother from when I started. I don’t recommend using this technique to tell when the board is smooth. your hand is usually close enough.
(C) Copyright Karson Morrison 6-22-2007, 6-23-2007 All right reserved.
-- I've been blessed with a father who liked to tinker in wood, and a wife who lets me tinker in wood. Southern Delaware firstname.lastname@example.org †