Tip #19
Sharpening Woodworking Tools (continued)
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Grinding Lathe Chisels

Lathe chisels can be ground on several Shopsmith machines. However using the Shopsmith Sharpening Guide with the disc sander, the belt sander or the strip sander is probably the easiest. Chisels can also be ground on the grinding wheel accessory but there is less apparatus to guide the chisels so accuracy is more difficult. Lathe chisels are held three different ways for scraping, cutting, and shearing. Therefore, they must be ground properly for the way they are going to be used. Some chisels can be ground and held to cut in more than one way while others are designed to cut stock one way only.

The skew and the gouge are generally ground for shearing with a long bevel and then honed to a razor sharp edge. They are intended to shear or cut (depending on how they are held) and are used to make spindle turnings. They can, however, also be ground and used as scraping tools.

The parting tool is ground for either cutting or scraping and is honed razor sharp only when it is intended for cutting. The roundnose chisel is generally ground with a short bevel and the burr is left on the cutting edge. This chisel is seldom honed and is intended to scrape. It is used to make both spindle and faceplate turnings.

Shearing chisels can be used to scrape and scraping chisels can be used to shear if this works best for you, but there are a few things to remember.

Warning: When any chisel ground to a shearing angle is used to remove stock with a scraping technique, especially with alternating grain direction, the sharp cutting edge will dig into the stock, stalling the machine or throwing the chisel and! or the stock. This will leave a deep gouge in the stockand possibly throw the tool from your hands causing injury and certainly damaging the tool.

Round bottom gouges, even when ground for scraping, will roll when the upper corners come in contact with the rotating stock causing them to dig into the stock. This will throw the tool from your hands possibly causing injury and certainly damaging the tool and the workpiece.

The double beveled chisels, skew and parting tool, are measured across both bevels. This is known as an included angle. (This angle includes both bevel angles.)

The longer the bevel or the smaller the angle ground on the chisel, means a sharper tool that will leave a smoother cut. However, the tool will be more difficult to control.

As you grind away metal, the chisel will become short and the handle ferrules will hit the sharpening guide, especially at the shearing settings. By then you will have ground past the heat treated end. For this reason, the chisel dulls quickly and needs to be replaced.

When you're using the disc sander or the belt sander mounted on the Mark V, always grind at “Slow” speed. For grinding on the strip sander, follow the recommended speeds for the different grits in the Owners Manual.

Because grinding removes metal with a moving abrasive working against a stationary metal tool, a great deal of frictional heat is created. To keep this heat from building up and destroying the factory heat treating and hardening of the tool (temper), hold the tool against the abrasive momentarily then slide it away. Repeat this procedure until the tool has been sufficiently ground. Caution: Have a container of water nearby to cool (quench) the tool if it becomes too hot to touch. If you notice that the too/is discoloring and turning blue, you are either holding the tool against the abrasive too long or too hard, the abrasive is dull or the speed setting is too fast.

When you're using the disc sander, the dust chute is used to contain the abrasive particles and protect the way tubes from grit. An alternative to using the dust chute is to place an 8" to 12" wide piece of scrap lumber on the way tubes under the sanding disc. Caution: When you're finished grinding, always slide the power plant away from the grinding position and wipe the way tubes clean.

Grinding Lathe Chisels using the Sharpening Guide
The Shopsmith Sharpening Guide mounts on the disc sander, belt sander and the strip sander and is used to grind skews, gouges, parting tools and roundnose chisels. Set up the machine you will be using and grind the chisels accord-ing to the applicable instructions below. To determine the sharpening guide angle settings, refer to Table 24-1.

Figure 24-6. To sharpen lathe chisels, mount the sharpening guide on the extension table only.

Disc Sander Setup-Mount the sharpening guide on the Mark V extension table (Figure 24-6). Warning: To sharpen lathe chisels, mount the sharpening guide to the extension table only. Mounting the guide to the worktable may cause the cutting edge of the chisel to dig into the abrasive and the tool to be thrown from your hands.

Adjust the sharpening guide to the desired angle setting. Slide the sanding disc to within 1/16" of the sharpening guide then secure the power plant lock. Warning: Never use the Velcro® Sanding System to grind tools.

Figure 24-7. Position the guide to within 1/16" of the belt.

Belt Sander Setup-Position the belt sander vertically and set the table to the “0” setting. Position the parting tool station of the sharpening guide in front of the belt sander backup plate. Adjust the guide to the desired angle setting. Warning: Position the sharpening guide to within 1/16" of the belt and secure the table locking setscrews (Figure 24-7).

Figure 24-8. Draw an index line 3-5/8" from, and parallel to the platen.

Strip Sander Setup-Set the strip sander worktable to 90° and adjust the sharpening guide to the desired angle setting. Because there are no table slots or mounting holes in the strip sander table, the sharpening guide must be clamped to the table top. An index line is used to align the guide. Draw this line 3-5/8" from, and parallel to the platen (Figure 24-8).

Figure 24-9. Clamp the sharpening guide to within 1/16" of the belt.

When setting the angle, position the hole in the rear of the sharpening guide and the angle setting indicator directly over the index line. Slide the sharpening guide along the line until the desired station is in front of the belt. Make sure the sharpening guide is within 1/16" of the belt, then clamp the guide securely to the table (Figure 24-9).

Grinding the Skew-The skew chisel has a bevel ground on both sides at an angle not perpendicular to either the side faces or the top and bottom edges. To grind this compound angle the skew must be held at an angle to the abrasive and leaned to the left and to the right. These angles are controlled by the sharpening guide.

Figure 24-10. Position the tip of the skew down and the side against the left wall of the second station.

Position the tip of the skew down and the side against the left wall of the second station of the sharpening guide (Figure 24-10). Be sure the skew is not touching the abrasive and the speed dial is set to “Slow” (if you are using the Mark V), then turn on the machine.

Gently slide the skew against the wall of the skew grinding station and into the moving abrasive. Hold the chisel there momentarily then back it away. Repeat this several times.

Figure 24-11. Position the tip of the skew up and the side against the right wall of the second station.

Turn the skew over and position the tip of the skew up and lay the side of the skew against the right wall of the second station (Figure 24-11).

Gently slide the skew against the station and into the moving abrasive. Hold it there momentarily then back it away. Repeat this several times.

Grind away only enough metal to remove any damage to the cutting edge and create a slight burr. If the skew is being ground for scraping, then it is ready to use (the burr is sharp and scrapes very well). If the skew is being ground for shearing or cutting, it will need to be honed to a razor sharp edge.

Grinding the Gouge-The gouge chisel has a bevel ground on the convex side (bottom) at an angle measured from the concave side (top). This bevel is curved to form a rounded cutting edge. To grind this complex curved bevel, the gouge must be held at the proper angle, fed into the abrasive and rotated. The angle is controlled by the sharpening guide.

Figure 24-12. Set the gouge in the third station and lay its side against the left wall.

Place the gouge in the third station of the sharpening guide and lay the side of the gouge against the left wall of the station (Figure 24-12). Rotate the gouge until its center touches the abrasive.

With the machine “OFF” prac-tice rotating the gouge, first clockwise from the center to the edge, and then counterclockwise from the center of the gouge to the edge.You should notice while rotating the gouge that in order to keep the bevel in contact with the abrasive, you must slide the gouge forward on the station as the bevel is ground from the center to each edge.

After you get the feel of this grinding motion, be sure the gouge is not touching the abrasive and the speed dial is set to “Slow” (if you are using the Mark V), then turn on the machine.

Gently slide the gouge against the wall of the station and into the moving abrasive. Start rotating the gouge, like you practiced. Repeat this several times.

Grind away only enough metal to remove any damage to the cut-ting edge and create a slight burr. If the gouge is being ground for scraping, it is ready to use (the burr is sharp and scrapes very well). If the gouge is being ground for shearing or cutting, it will need to be honed to a razor sharp edge.

Grinding the Parting Tool- The parting tool has a bevel ground on both the top and bottom edges. To grind these angles the parting tool must be held on its side at the proper angle to the moving abrasive, turned over and reset at the exact same angle. These angles are controlled by the sharpening guide.

Figure 24-13. Set the parting tool's side in the first station.

To grind the parting tool, lay the side of the parting tool in the first station of the sharpening guide (Figure 24-13). Be sure the parting tool Is not touching the abrasive and the speed dial is set to “Slow” (if you are using the Mark V), then turn on the machine.

Gently slide the parting tool on the station and into the moving abrasive. Hold it there momentarily then back it away. Repeat this several times.

Turn the parting tool over and lay the other side in the first station. Slide the parting tool on the station and into the moving abrasive. Hold it there momentarily then back it away. Repeat this several times. Grind away only enough metal to remove any damage to the cutting edge and create a slight burr. It is VERY important to grind an equal amount from each bevel so that the widest part of the parting tool is exactly at the cutting edge. If the parting tool is being ground for scraping, then it is ready to use (the burr is sharp and scrapes very well). If the parting tool is being ground for cutting, it will need to be honed to a razor sharp edge.

Grinding the Roundnose Chisel-The roundnose chisel has a bevel ground on the bottom at an angle measured from the top. This bevel is curved to form a round cutting edge. To grind this curved bevel the roundnose chisel must be held at the proper angle to the moving abrasive, pivoted and fed into the abrasive. The bevel angle is controlled by the sharpening guide.

Grinding the roundnose chisel on the fourth station is the only grinding operation that does not repeat the “factory” angle. The new 15° bevel angle is ideal for scraping. The distance between the pivoting station and the moving abrasive will set the radius of the cutting edge. Position the pivoting station close to the abrasive and the cutting edge will be ground completely around the chisel leaving no sharp corners. Position the pivoting station further away from the abrasive and the cutting edge will be ground around the chisel on a large radius leaving sharp corners where the sides and the curved cutting edge join.

Figure 24-14. Position the roundnose chisel, bevel up in the fourth station. Tighten the knob.

To grind the roundnose chisel, position it, bevel up in the fourth station (the pivoting station). Slide it under the knob until the center of the round nose chisel touches the abrasive and tighten the knob (Figure 24-14).

With the machine “OFF” practice pivoting the roundnose chisel first to the left, and then to the right to complete the edge. You will notice that the chisel will need to be repositioned further forward on the grinding station to complete the bevel. After you get the feel of this grinding motion, be sure the round-nose chisel is not touching the abrasive and the speed dial is set to “Slow” (if you are using the Mark V), then turn on the machine.

Gently slide the roundnose chisel in the fourth station until it just touches the moving abrasive. Tighten the knob and start pivoting the roundnose chisel, like you practiced. Repeat this several times.

Grind away only enough metal to remove any damage to the cutting edge and create a slight burr. The roundnose chisel is ground for scraping, so it is ready to use as is and should not be honed (the burr is sharp and scrapes very well).

Grinding Lathe Chisels using the Grinding Wheel
The Shopsmith Grinding wheel mounts on the Mark V and will grind skews, gouges, parting tools and roundnose chisels. Set up the grinding wheel on the Mark V and grind the chisels according to the applicable instructions below.

Grinding the Skew-The skew chisel has a bevel ground on both sides at an angle not perpendicular to either the side faces or the top and bottom edges. To grind this compound angle the skew must be held at the proper angle to the side of the wheel and leaned to either the left or to the right on the appropriate sides of the wheel. Warning: Do not grind the skew on the front of the wheel. This will leave a hollow ground bevel on the skew that may make the chisel difficult to control.

One angle is controlled by the tool rest and the other angle (the lean of the tool) is controlled by feel.

Figure 24-15. Hold the skew on the tool rest with the tip up and the bevel against the wheel.

To find the desired tool rest angle setting hold the skew on the tool rest with the tip up and the bevel of the cutting edge against either side of the wheel. Loosen the wing nut and pivot the tool rest until the cutting edge is parallel to the rotation of the wheel (Figure 24-15). At the same time, slide the tool rest to within 1/16" of the wheel and then secure the wing nut.

Figure 24-16. Position the tip up, and lay the right side bevel against the left side of the grinding wheel.

To grind the skew, position the tip up and lay the right side bevel against the left side of the grinding wheel (Figure 24-16).

Tilt the skew away from the wheel and be sure the skew is not touching it and the speed dial is set to “Slow”. Then turn on the Mark V and set the speed dial to “R” (3400 RPM).

Gently lean the skew back toward the side of the grinding wheel. Feel for the bevel of the skew against the side of the grinding wheel. Hold it there momentarily then lean it away. Repeat this several times.

Figure 24-17. Position the left bevel, with the tip up, near the right side of the wheel.

Reposition the left bevel with the tip up near the right side of the wheel (Figure 24-17).

Gently lean the skew into the side of the grinding wheel. Feel for the bevel of the skew against the side of the grinding wheel. Hold it there momentarily then lean it away. Repeat this several times.

Grind away only enough metal to remove any damage to the cutting edge and create a slight burr. If the skew is being ground for scraping, then it is ready to use (the burr is sharp and scrapes very well). If the skew is being ground for shearing or cutting, it will need to be honed to a razor sharp edge.

Grinding the Gouge-The gouge chisel has a bevel ground on the convex side (bottom) at an 293 angle measured from the concave side (top). This bevel is curved to form a rounded cutting edge. To grind this complex curved bevel, the gouge must be held at the proper angle to the grinding wheel, rotated and fed into the wheel. The angle and the roll of the gouge is controlled by feel.

Figure 24-18. Practice rolling the gouge toward the front of the tool rest. Feel the bevel seat on the wheel.

Set the tool rest to 90° and slide it to within 1/16" of the wheel and then secure the wing nut. Set the gouge on the tool rest with the cen-ter of the bevel against the front of the grinding wheel and the handle pointing to the left.

Practice rolling the gouge toward the front of the tool rest (Figure 24-18). Feel for the bevel against the grinding wheel while keeping the side firmly against the tool rest. Repeat this movement with the gouge handle pointing to the right (Figure 24-19).

Figure 24-19. Roll the gouge to the front of the tool rest, this time with the handle pointing to the right.

When you feel confident with the rolling movement of the gouge, slide it away from the wheel. Be sure that the gouge is not touching the wheel and that the speed dial is set to “Slow”. Then turn on the Mark V and set the speed dial to “R” (3400 RPM).

Gently slide the gouge into the grinding wheel. Feel for the bevel of the gouge against the grinding wheel. Roll the gouge just as you practiced, first with the handle to 294 the right, then with the handle to the left. Repeat this several times.

Grind away only enough metal to remove any damage to the cutting edge and create a slight burr. If the gouge is being ground for scraping, then it is ready to use (the burr is sharp and scrapes very well). If the gouge is being ground for shearing or cutting, then it will need to be honed to a razor sharp edge.

Grinding the Parting Tool- The parting tool has a bevel ground on both the top and bottom edges. To grind these angles the parting tool must be held on its edge at the proper angle to the grinding wheel, turned over and held at the exact same angle. Adjust the tool rest to match the center of the bevel previously ground on the parting tool and slide the tool rest to within 1/16" of the wheel and then secure the wing nut.

Figure 24-20. Lay the parting tool edge on the tool rest as shown.

Lay the edge of the parting tool on the tool rest (Figure 24-20). Practice sliding the tool forward while holding it perpendicular to the tool rest and the grinding wheel. Try this on both sides of the parting tool.

When you feel confident with the movement of the parting tool, slide it away from the wheel. Be sure that the parting tool is not touching the wheel and that the speed dial is set to “Slow”. Turn on the Mark V and set the speed dial to “R” (3400 RPM).

Gently slide the parting tool on the tool rest and into the grinding wheel. Hold it there momentarily then back it away. Repeat this several times.

Turn the parting tool over and lay the other edge on the tool rest. Slide the parting tool on the tool rest and into the grinding wheel. Hold it there momentarily then back it away. Repeat this several times.

Grind away only enough metal to remove any damage to the cutting edge and create a slight burr. Be sure to grind an equal amount from each side so that the widest part of the parting tool is exactly at the cutting edge. If the parting tool is being ground for scraping, then it is ready to use (the burr Is sharp and scrapes very well). If the parting tool is being ground for cutting, itwill need to be honed toa razor sharp edge.

Grinding the Roundnose Chisel-The roundnose chisel has a bevel ground on the bottom at an angle measured from the top. This bevel is curved to form a rounded cutting edge. To grind this curved bevel the roundnose chisel must be held at the proper angle to the grinding wheel, pivoted and fed into the wheel. The bevel angle is controlled by the tool rest.

Set the tool rest to a 5° to 10° angle to the wheel and slide the tool rest to within 1/16" of the wheel. Then secure the wing nut.

Figure 24-21. Slide the chisel, bevel down, until its center touches the grinding wheel.

Grinding the roundnose chisel is the only grinding operation that does not repeat the “factory” angle. The hollow-ground 50 to 10° bevel angle is excellent for scraping. Set the roundnose chisel, bevel down on the tool rest. Slide the chisel forward until the center of the chisel touches the grinding wheel (Figure 24-21).

With the machine “OFF” practice pivoting the roundnose chisel first to the left, and then to the right to complete the edge. After you get the feel of this grinding motion, be sure the roundnose chisel is not toucriing the wneel and that the speed dial is set to “Slow”. Turn on the Mark V and set the speed dial to “R” (3400 RPM).

Gently slide the roundnose chisel on the tool rest and into the grinding wheel. Like you practiced, pivot the chisel to grind the bevel.

Grind away only enough metal to remove any damage to the cutting edge and create a slight burr. The roundnose chisel is ground for scraping, so it is ready to use as is and should not be honed (the burr is sharp and scrapes very well).

Continue to Honing Lathe Chisels
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