BIG TREE TOOLS
SHARPENING SYSTEM
SHARPENING MACHINE
TO SET UP THE MACHINE
1. Attach the machine to the baseboard with the four carriage bolts. The nuts require a 1/2 inch wrench.
2. Loosen the 14 mm nuts (2) which clamp the pivot at the lower shaft. One of the nuts is slightly behind the belt guard, but is accessible with the thin wrench provided. Lift the platen into vertical position, and tighten the clamp nuts.
3. Install the buffing guard, but do not tighten the nut yet.
4. Attach the buffing wheel with the hex key provided (3 mm). Make sure the set screw fits onto the flat in the shaft.
5. Adjust buffing guard into final position, and tighten nut.
6. Install the abrasive belt.
PRINCIPLE OF OPERATION
The BTT sharpener is a belt/buff system converted from a standard 4 x 36 belt sander. The BTT sharpener uses an incremental V-block jig for positioning turning chisels for sharpening. This makes it possible to replace the block in exactly the same place each time the machine is used for a particular chisel. Because the angle is exactly the same each time, a minimum amount of metal is removed, which saves time, prolongs tool life, reduces heat, and abrasive dust. The system is accurate and fast, usually requiring less than 10 seconds total time for set up, grinding and buffing.
The machine is supplied with coarse, medium and fine belts. This size (4 x 36) abrasive belt is an extremely common size, and available from many sources. Use the coarse (80) for rough shaping, the medium (150) for turning chisels, and fine (240) for carving chisels and plane blades.
INSTRUCTIONS FOR SHARPENING TURNING CHISELS
1. The first time you use the machine, each chisel must be brought to the angle which is fixed by the V-block. Set the V-block in the position which gives the angle closest to the angle you desire.
2. If you have new chisels which need modification and/or you want to make a large change in the angle or shape of the grind, use the 80 grit coarse belt for this operation, or in some cases start with a grinding wheel.
3. Once you have achieved the correct geometry, use the 150 or 240 belt to obtain and maintain the perfect edge.
4. Apply the buffing compound (provided) to the buffing wheel. Compound will need to be applied liberally at first, as the wheel is being broken in. After that, apply compound occasionally. Compound is required for the buffing wheel to work.
5. After grinding with the belt, use the buffing wheel for a few seconds. Buff mostly on the inside of the gouge, since this is where the burr comes up. For skew chisels, grind on both sides, then buff on both sides.
6. Do not buff too much! It is only necessary to take off the burr left by the belt. The buff should only take a few seconds.
7. After many sharpenings (about 1,000), the chisel will become shorter, and will have to be moved up one step on the board. Use a coarse belt to regrind to the new angle.
8. If the pins on the V-block are too tight in certain positions, use paraffin on the pins. The holes can be reamed with a 1/4" drill, but be aware that the fit will loosen up over time.
9. Many methods have been devised for remembering which step to place the V-block for each chisel. Color codes work well. Labels can be placed on the board corresponding to the name/size of the chisel. With the block in place, draw a line underneath. This will aid in lining up the pins visually and makes it quicker to reset the block.
10. To use a SIDE GRIND ADAPTOR, see instructions for the Versa-Jig.