A chisel, a wooden handle, a piece of steel with a sharp edge on one end and a hammer on the other end. Although the shape is extremely simple, it is the most important "weapon" for woodworkers.
Many beginners in woodworking always have these doubts about chisels:
I think Paul Sellers can answer these questions very well. Paul is one of the top 10 woodworkers in the world. Since he began his career in woodworking in 1965, he has been immersed in the world of woodworking for more than half a century and has written the book Essential Woodworking Hand Tools. In later life, he spares no effort to share the skills of debugging and polishing various hand tools.
Today's article is about how Paul sharpened chisels with diamond and sandpaper. He suggested that diamonds are the best choice for grinding chisels, but beginners can also use sandpaper to transition and then move on to diamonds after they get the hang of it.
Note. Be careful when sharpening the chisel and make sure the blade is pointing away from you when you are sharpening the chisel as the chisel gets sharper as it is sharpened.
Grinding chisels with diamondsIn the process of using a diamond grinding bit, you will need the following materials:
①Three grades (coarse, fine, ultrafine) or other grades of diamond sharpening
② Auto glass cleaner
③Polishing agent
④A piece of plywood 19mm thick, 76mm wide, and 254mm long, with leather glued on the surface
01
Face grinding
Whether your chisel is new or used, check it for flatness first, then sand and polish as needed. Starting on the rough side, press down on the support with one hand, then place the chisel flat with the other hand, swiping back and forth.
After a few light sandings, you can turn the chisel over and evaluate the degree of grinding. If you notice that only some areas are heavily ground, then the bit is not ground.
In the grinding process, while the cutting edge itself or even the back of the cutting edge is ground, it is not necessary to grind the entire surface of the bit.
In the process of grinding the chisel, first use the rough grade, then use the fine grade, and finally use the super fine diamond to grind, the effect will be better.
When grinding with a fine-grained diamond, place the chisel lengthwise on the grinding plate. To prevent wear on the handle by the diamond blade, rotate the handle towards the body, stand on the side and press down on the chisel. fingers to start grinding.
We then use the wood side of the plywood to polish and remove any remaining signs of wear.
First, hold the plywood in a vise with the wooden side up and rub in a waxy polish containing an abrasive that will eventually polish the surface of the chisel, pressing it well into the board.
Fill the plywood with polish
In the process of polishing the chisel, the surface of the plywood began to blacken. This is due to the fact that the abrasive grinds the steel, changing the color of the mixture. At this point, you can simply remove the excess paste from the chisel with a rag or paper towel. If that doesn't work, try thin steel wool.
Push and drag the chisel back and forth across the plywood to sharpen the blade
02
Chamfer grinding
Because water can leave rust on the diamond plate, we can use glass cleaner instead of water. When sanding the bevel of a chisel, spray glass cleaner onto the sharpening boards, usually one pump per board is sufficient.
Place the chisel with the beveled side down on the coarse grinding board. Apply pressure evenly to the bevel of the chisel, press and pull along the sharpening plate several times, about 10 times as a group, and apply even pressure along the grinding plate.
Rough diamond polishing effect
Most of the grinding is done on a coarse grinding board. The chisel starts grinding at about 30° and finishes between 20-25° each time. The beveled cutting edge, ground in this way, creates a smooth curve towards the bit.
Repeat the above steps for thinner, medium quality boards, and finally for ultrathin boards.
After following the above two steps, burrs form on the cutting edge of the bevel. To remove burrs: Turn the chisel over, press the flat side against the sharpening plate, push down on the top of the chisel and pull the chisel back (away from the cutting edge) in one motion.
Next, we polish the bevel of the chisel.
Start with the plywood side up. Then apply varnish on the leather side. Place the chisel beveled down and pull back hard about 30 times to polish and remove any wear marks. Be sure to pull back gently as the chisel may dig into the skin when pressed.
Finally, carefully remove the remaining wax with a cloth or napkin.
After carefully polishing the surface, the cutting edge becomes very sharp
Grinding the chisel with sandpaperIf you are using sandpaper to sharpen your chisel, you will need the following materials:
①Sandpaper strips (approximately 228.6mm x 88.9mm) 80 or 150 coarse sandpaper, 400, 800, 1500, 2000, 3000 fine sandpaper (2 sheets each), or as close as possible to them graininess
②Spray glue
③Tile, about 9" * 9" (228.6mm)
④Sharpening stand
⑤Ruler
01
Preparation process
Spray the adhesive on the back of the coarsest sandpaper, then apply to the tile and press firmly. If your tiles are large enough, you can also glue on a few more strips of sandpaper.
Whether you're buying a new or used chisel, it's important to improve the flatness of the edge and sand the back of the chisel.st chisels. You have to make sure the surface you are sharpening the chisel on is really flat and while ceramic tiles are recommended here, some tiles are uneven so be sure to use a square to check the flatness of the tiles.
02
Grinding the plane
With the chisel flat side down, start with the coarsest sanding paper (80 or 150 grit) and rub the chisel back and forth. Press the bearing with one hand and the chisel down with the other hand, after a few sharpenings you can turn the chisel over and see if you find that only certain areas are poorly ground, indicating that the chisel has not been ground.
Once the chisel has been ground to the cutting edge, no further grinding is necessary. Sand with varying grit sandpaper, then wipe off excess steel from the chisel with a cloth or paper towel.
Tips ↓↓
It is recommended that you sand the wood side of the plywood and remove any remaining sanding marks, this will give your chisel a "power boost".
Place the plywood in the vise with the wooden side up. Rub the polish well into the wood to coat the wood surface, and the wax contains very fine particles to polish the flat surface of the chisel.
When polishing a chisel, the wooden surface begins to blacken, because the abrasive grinds the steel, changing the color of the paste. Wipe off excess paste from the chisel with a cloth or paper towel, or if it doesn't work, fine steel wool.
03
Chamfer grinding
When using sandpaper to grind the bevel of a chisel, we need to use a sharpening tool - a whetstone to help the beginner apply the force evenly.
Place the chisel on the sharpening stand and tilt it down. If you want to sharpen a bevel up to 25°, you need to extend the chisel blade out of the grinder by 40mm (this data may differ for different grinders). Check with a ruler if necessary.
Place the chisel in the sharpening stand, bevel the coarse sandpaper. Apply even pressure to the sharpening block and pull evenly along the paper about 10 times to create a fixed angle bevel.
Most sanding takes place on coarse sandpaper, so this process takes the most time.
The subsequent sanding is basically a simple chamfer sanding. Once the bevel is determined to be 25°, adjust the chisel in the sharpening stand from 40mm to 30mm and use the finest sandpaper to start sanding at the 30° position and the sanding width should be only 1-2mm.
Finally, you need to sand by hand using 3 different grades of sandpaper to create a smooth bulge from the edge of the cut to the heel of the bevel.
When sharpening a chisel, you may feel very fine burrs forming on the cutting edge of the bevel on the back planebits.
To remove burrs, turn the chisel over with the flat side pressed against the sharpening board, push down on the top of the chisel until the surface on the sharpening board is completely flat, and pull the chisel toward you once.
If you are using plywood for further bevelling, fill the leather side with polish, place a chisel and pull back hard about 30 times to polish and remove any wear marks present. Gently run the chisel over the leather surface, leading it to the back of the cutting edge, and finally carefully remove any remaining wax with a cloth or tissue paper.
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