Cutters have been installed on the head (See article: Installation of cutters on a finger joint head) and now it’s time to post the cutter stacks and tighten the nuts to the specified torque value. The set-up stand must be bolted to a stable workbench.
- All nuts and washers should have been installed with anti-seize compound. Nuts should be no more than finger tight at this point. Do not allow anti-seize to get between the cutters or cutters and top plate and bottom surface of the heads.
- Rotate all the cutter stacks back toward the center mast of the head before placing the head on the multi-post set-up stand. The bottomed-out stacks will allow maximum clearance between the cutters and the alignment posts when lowering the head into position.
- Verify that the alignment dowel/torqueing dowel is placed in the center position. There are three locating holes drilled into the bottom plate of the set-up stand. The center hole is for aligning the cutters. The left and right pin locations are for torqueing: the left hole for right hand threads/clockwise rotating heads and the right hole for left and right hand threaded bolts/counter clockwise rotating heads.
- Slowly lower the head onto the mast of the set-up stand. DO NOT DROP the HEAD. Verify that the alignment dowel is safely inserted into the machined recess of the bolt head. Always install “bolt # 1” down on the alignment dowel each time the cutters are aligned or re-posted. This will aid in identifying any alignment or grinding issues that may arise in the future.
- Lightly position the cutters against the alignment post from the top of the stack downward. If the cutters are difficult to move, it may be necessary to loosen the nuts on the adjacent bolts slightly. It is also helpful to use a pull up tool to rotate the cutters against the alignment post. Do not use excessive force when positioning the cutters against the alignment post, as distortion of the post may result.
- Once all the cutter stacks have been posted, examine to verify that all cutters in each stack are against the alignment post.
- As each cutter stack is aligned against the post, lightly tighten each nut with a wrench. Grip the head of wrench to avoid overtightening. Typically, this is where the cutters will move away from the alignment post on counter clockwise rotation heads with bolts with right hand threads. Left hand bolts will eliminate this as the cutters are rolled toward the alignment post when tightened.
- When all cutter stacks have been positioned against the alignment post and the nuts lightly tightened, check all cutters on all stacks with a .002” (.050mm) thick piece of shim stock. The shim should be cut to a point approximately 0.040” (1mm) in width so each individual cutter may be checked. If the .002” (.050mm) shim can be inserted between the cutter and post, that cutter is not posted correctly and must be pulled against the alignment post before proceeding. Loosen the nut, repost the cutter and recheck the stack. This check will reduce the grinding time required to clean up all cutters.
- When all cutter stacks have been checked, rotate the head back away from the alignment post to the pin location for torqueing. Again: the center hole is for aligning the cutters. The left and right pin locations are for torqueing: the left hole for right hand threads/clockwise rotating heads and the right hole for left and right hand threaded bolts/counter clockwise rotating heads.
Do not torque bolts with cutters against the alignment post.
- Torque all nuts to 25 ft/lb (35 Nm) in a crisscross pattern. See the diagram below.
- Rotate the head to the alignment pin location again and recheck with .002” (0.50mm) shim as outlined in step 8. Reposition any rolled back cutters against the alignment post. You will have to back the nut off to reposition the cutters. If the cutters are difficult to move, it will be necessary to loosen the nuts on the adjacent bolts.
- When all cutter stacks have been checked and corrected, reposition head on the correct torqueing pin and proceed with torqueing in a crisscross pattern in 50 ft/lb (70 Nm) increments.
- A minimum torque of 150 ft/lb (205 Nm) should be applied to 3/4” bolts with stack heights below 1.500”. As stack height increases, torque must also increase. Do not exceed 250 ft/lb (340 Nm) on 3/4” (19mm) bolts.
- When all bolts have been torqued to the proper value, repeat the torqueing sequence one final time.
***Always have your torque wrench calibrated at least once every year.
***Never use a torque wrench to break loose a tightened nut.
***Always use a breaker bar to loosen the nuts.