Card scraper must be one of the simplest woodworking tools of all. A mere thin piece of steel does not look like it would be a powerful cutting tool capable of making the finest and smoothest surface on the hardest of woods. However, properly used and understood how it works, it is really an efficient cutting tool. I have collected some tips and tricks with which you could get more out of this awesome versatile tool.
Heat management tips
Certainly, everyone who is sometimes used cabinet scraper has noticed that it heats like a crazy when used for a prolonged period. A heat is produced by the cutting resistance and because the scraper is a thin and light piece of steel, it gets hot very fast. Especially thumbs are in danger of getting blisters or burns if you get inspired to use it too long. I remember the first time when I managed to sharpen the card scraper to cut great shavings, I was so excited to cut beautiful shavings that I got water blisters on both of my thumbs. With these tips, you can effectively reduce or prevent burning your thumbs.
- This tip comes from the old timers of woodworking. One annoying feature with the scraper is the extreme heat produced when scraping vigorously. It can burn your thumbs causing painful blisters. An easy way to prevent this is to use several scrapers in a row. When one gets too hot, lay it down to the table to cool off and continue to scrape with another cool one. Large areas are scraped efficiently with a couple of scrapers. Another good thing is that with couple scrapers you have more fresh cutting edges to dull and to cycle through before needing to sharpen them again!
- Another good trick is to use something as an insulation between the thumbs and the cabinet/card scraper. A flexible fridge magnet is handy and works well as a heat shield for a single cabinet scraper. It is easy to reposition or switch to the other side when flipping the scraper over. I tried sometimes painter masking tape and it worked well although the heat burned the glue onto the scraper making it difficult to remove when ti was time to sharpen the scraper again.
- You can also make leather thumb covers from old leather work gloves by cutting the tips off, to protect your thumbs from burning.
- Dedicated scraper holder like the Veritas Scraper Holder eases the use of cabinet or card scraper in many ways. Burned and fatigued thumbs are relieved when the scraper holder insulates and takes care of bending the scrapers with an adjustment screw. The Veritas Scraper Holder is highly recommended, particularly with arthritic hands. Scraper holder can also be shop-built from a piece of wood.
Scraper sharpening and maintaining tips
Sharpening the card scraper may seem arcane or mysterious for the uninitiated. It is incredible how the innocent looking piece of steel can cut thin shavings as a state of art smoothing plane. Here are a couple tips about the scraper sharpening and maintaining the great cutting edge. You should also read my in-depth guide about cabinet scraper sharpening.
- The scraper can be burnished a couple times before you really need to file and hone the edges again. First, draw the burr straight along the face, then turn the burr by swiping along the edge couple times starting by holding the burnisher level and steepening the angle with every swipe.
- You can get very aggressive cutting scraper by using the file only, no honing. File the edges square and draw and burnish the edges as usual. The drawback with this method is that the edge is not very durable due to the roughness and needs to be re-filed often, and the surface quality is worse compared to thoroughly sharpened and honed scraper. An aggressive cutting action is useful when scraping of paint or lacquer.
- A good quality burnisher is an important tool when sharpening any scraper. Take care of your burnisher. Buff the burnisher if it has any nicks or scratches. Any imperfection will hinder the burnished edge quality breaking and tearing the microscopic burr.
- Remember always to use oil when burnishing. You get better quality and longer lasting edge with an oiled burnisher. If you don’t have the suitable oil with you, swipe your fingertips along your nose and then along the edge to be burnished. Skin oils work as well as any other oils
- The Ruler Trick, by David Charlesworth, is a really useful trick when sharpening the scrapers. It speeds up the honing process of the faces when only the narrow area along the edge honed, just like when honing the back of the plane blades.
- Burnishing the face gives a burr that lasts longer because the steel is work-hardened by the hard burnisher. The burr formed is more perfect and flemish–free and it will, therefore, last longer.
- Rectangular card scrapers have 4 sides. You can burnish them with different angles, one or two edges for more aggressive work and other for finer finishing work or prepare them same way so you don’t have to sharpen as often.
- Remember to store the scrapers right. They are cutting tools that must have sharp edges to work perfectly. Do not allow the cutting edges to come in contact with other scrapers or metallic objects. Sew a tool-roll with individual pockets for storing the scrapers or make a wooden scraper blade holder with slits sawn in it to keep the scrapers away from each other.
- Use the old hand saw blades as a source of material for new scrapers. Thin used Japanese saw blades are good for delicate scrapers for luthiery. With good tin snips, you can cut any shape from the saw blade. Note though that Japanese saw blades are harder and require a properly hardened burnisher rod to turn the burr properly. They are sometimes so hard that even a file skips over it and you need to use bench stone or grinding as a substitute for a file.
- Industrial razor blades are good touch up scrapers when finishing, they work without needing to turn the burr.
- For touch up work when finishing, tape the corners of the scraper to prevent the scratching the surface accidentally
- Methodical scraping is the key for flat surfaces. Do not stay in one place too long or you can leave a hollow that will show after the finish is applied. When removing local flaw, it is a good habit to take two strokes either side of the flaw for every stroke on it. Also, try to cover as much ground as possible with each stroke. This way you blend the repair and the resulting surface will be perfect
- In veneered surface only cutting tool precise enough is the scraper. Veneers are many times mere 0,6mm thin and you can easily cut through them with power sanders. The bond between the veneer and backing can be too weak and can release accidentally if the veneered surface is cut with a plane. Recommended methods for cleaning the veneered surface are scraping and hand sanding.
- Scraping softwoods like spruce: For best results in softwoods, you need scraper with a very sharp and light burr. Use very, very little pressure when turning the burr and usually single stroke is enough. It will scrape Spruce readily, producing shavings rather than dust. A sharp scraper also emits a certain sound. The scraper will leave a little corduroy texture on the Spruce.
- Sometimes card scrapers and planes leave too smooth a surface for some finishes, especially stains. When staining the wood after scraping you need to roughen the surface bit with sandpapers so it will properly take stain.
- Card scraper cuts better when skewed to about 30°.
- Like in hand planes, same basic principles apply: Work with the grain of the wood, and not against it or across it. The scraper is not the holy grail of the gnarly grain, you still need to read the grain and scrape accordingly
- Get card/cabinet scrapers with different thickness. Thinner the scraper the finer the work and vice versa. Thick scrapers are for rough and fast material removal.