HITACHI Compound Miter Saw C 12LDH User Manual

  • Post last modified:May 19, 2023
  • Post category:HITACHI


HITACHI Compound Miter Saw C 12LDH


Specific Safety Rules for Use of this Power Tool


  1. Review this Manual and familiarize yourself with the safety rules and operating instructions for this POWER TOOL before attempting to use it.
  2. Always confirm that the POWER TOOL is clean before using it.
  3. Always wear snug-fitting clothing, non-skid footwear (preferably with steel toes) and eye protection when operating the POWER TOOL.
  4. Always handle the POWER TOOL carefully. If the POWER TOOL falls or strikes against a hard object, it might become deformed or cracked or sustain other damage.
  5. Always cease operating the saw at once, if you notice any abnormality whatsoever.
  6. Always confirm that all components are mounted properly and securely before using the tool.
  7. When replacing the saw blade, always confirm that the rpm rating of the new blade is correct for use on this tool.
  8. Always shut off the power and wait for the saw blade to completely stop rotating before doing any maintenance or adjustments.
  9. Always clamp or otherwise secure the workpiece to the fence; otherwise the workpiece might be thrust form the table and cause bodily harm.
  10. During miter or bevel cutting, always wait for the rotation of the blade to stop completely before lifting the saw blade.
  11. Always make a trial run first before attempting any new use of the saw.
  12. Always handle the saw blade with care when dismounting and mounting it.
  13. Always confirm that the workpiece is free of nails or other foreign objects before beginning a cut.
  14. Always keep your hands out of the path of the saw blade.
  15. Always confirm that the lower guard is in the proper place before using the saw.
  16. Inspect the tool power cords periodically.
  17. Always confirm that the proper lengths and types of extension cords are being utilized, if necessary, before starting the tool.
  18. Always confirm that the motor air vents are fully open before using the tool.
  19. Always wait until the motor has reached full speed before starting a cut.
  20. Always keep the handles dry, clean and free of oil and grease. Hold the tool firmly when in use.
  21. Always use outboard stands to provide support for long workpieces that overhang the table of the compound miter saw.
  22. Always operate the tool after ensuring the workpiece is fixed properly with a vise assembly.
  23. The operating instructions provided with the tool shall direct the user to secure the tool to supporting structure if, during normal operation, there is a tendency for the tool to tip over, slide, or walk on the supporting surface.


  1. Never operate the POWER TOOL unless you fully understand the operating instructions contained in this Manual.
  2. Never leave the POWER TOOL unattended without first unplugging the power cord.
  3. Never operate the POWER TOOL when you are tired, after you have taken any medications, or have consumed any alcoholic beverages.
  4. Never use the POWER TOOL for applications not specified in the instruction manual.
  5. Never operate the tool while wearing loose clothing, a necktie or jewelry, or while your hair is uncovered, to protect against getting caught in the moving machinery.
  6. Never reach around the saw blade.
  7. Never touch any moving parts, including the blade, while the saw is in use.
  8. Never remove any safety devices or blade guards; use of the tool without them would be hazardous.
  9. Never lock the lower guard; always confirm that it slides smoothly before using the tool.
  10. Never damage the power cord of the tool.
  11. Never attempt to move a plugged-in POWER TOOL while your finger is on the starting switch.
  12. Never use the POWER TOOL if the starting switch does not turn on and off properly.
  13. Never use the POWER TOOL if the plastic housing or the handle is cracked or deformed.
  14. Never use the POWER TOOL near flammable liquids or gases because sparking can cause an explosion.
  15. Never clean plastic components with solvents because the plastic may dissolve.
  16. Never operate the saw unless all the lower guards are in place.
  17. Never raise the saw blade from the workpiece until it has first come to a complete stop.
  18. When slide cutting, never pull the handle toward the operator, since this could cause the saw blade to kick up from the workpiece. Always push the handle away from the operator in a single, smooth motion.
  19. Never place your limbs inside of the line next to warning sign “ ” while the tool is being operated. This may cause hazardous conditions.
  20. Never use abrasive type blades on this saw.
  21. Never expose to rain or use in damp locations.
  22. Never cut ferrous metals or masonry.


  1. Always wear eye protection when using the compound miter saw.
  2. Always keep hands out of the path of the saw blade.
  3. Never operate the saw without the guards in place.
  4. Never perform any freehand operation with the compound miter saw.
  5. Never reach around the saw blade.
  6. Always turn off tool and wait for saw blade to stop before moving workpiece or changing settings.
  7. Always disconnect power before changing blade or servicing.
  8. Saw blade diameter is 12” (305 mm).
  9. No load speed is 4,000/min.
  10. To reduce the risk of injury, return carriage to the full rear position after each crosscut operation.

When servicing use only identical replacement parts. Repairs should be conducted only by a Hitachi authorized service center.


Make sure your extension cord is in good condition. When using an extension cord, be sure to use one heavy enough to carry the current your product will draw. An undersized cord will cause a drop in line voltage resulting in loss of power and overheating. Table shows the correct size to use depending on cord length and nameplate ampere rating. If in doubt, use the next heavier gage. The smaller the gage number, the heavier the cord.

                                                        MINIMUM GAGE FOR CORD SETS                                _____________

                                             Total Length of Cord in Feet (Meter)                                            ______                         0 – 25 (0 – 7.6)                26 – 50 (7.9 – 15.2)         51 – 100 (15.5 – 30.5)          101 – 150 (30.8 – 45.7)

Ampere Rating

More Than   Not Than

0 – 6 18 16 16 14
6 – 10 18 16 14 12
10 – 12 16 16 14 12
12 – 16 14 12 Not Recommended



To ensure safer operation of this power tool, HITACHI has adopted a double insulation design. “Double insulation” means that two physically separated insulation systems have been used to insulate the electrically conductive materials connected to the power supply from the outer frame handled by the operator. Therefore, either the symbol “ ” or the words and “Double insulation” appear on the power tool or on the nameplate. Although this system has no external grounding, you must still follow the normal electrical safety precautions given in this Instruction Manual, including not using the power tool in wet environments. To keep the double insulation system effective, follow these precautions:

  • Only HITACHI AUTHORIZED SERVICE CENTER should disassemble or assemble this power tool, and only genuine HITACHI replacement parts should be installed.
  • Clean the exterior of the power tool only with a soft cloth moistened with soapy water and dry thoroughly.
  • Never use solvents, gasoline or thinners on plastic components; otherwise the plastic may dissolve.





Item Model C12LDH C12FDH
Motor Type Series commutator motor
Power source Single-phase AC 60Hz
Voltage (Volts) 120
Full-load current (Amp) 15
Digital Display Precision ±0.5° Yes No
Laser Marker Yes Yes
Maximum output <1mW CLASS II Laser Product
Wave length 400~700 nm
Laser medium Laser Diode

saw blade

Outside Dia. 12” (305mm)

Hole Dia. 1” (25.4mm)

No load speed 4000/min

sawing dimension

Head Turntable Max. sawing dimension
Miter 0 0 Max. Height Max. Width or

Max. Height

Max. Width





(70mm) (203mm)



0 Left     45°


Max. Height

Max. Width





0 Left     52°


Max. Height

Max. Width





Bevel Left 45° 0 Max. Height    1-31/32”(50mm)

Max. Width      8”          (203mm)

Right 45° 0 Max. Height

Max. Width





Compound Left 45° Left     45°


Max. Height     1-31/32”(50mm)

Max. Width      5-1/2” (140mm)

Right 45° Left     45° Right Max. Height

Max. Width





Miter sawing range Left 0° – 52° Right 0° – 52°
Bevel sawing range Left 0° – 48° Right 0° – 48°
Compound sawing range Left and Right (Bevel) 0° – 45°, Left and Right (Miter) 0° – 45°
Net weight 47.4 lbs. (21.5 kg) 46.3 lbs. (21.0 kg)
Cord 2 Conductor type cable 6.7 ft. (2.0m)





  1. Extension Holder and Stopper (Code No. 323523)
  2. Crown molding Vise Ass’y (Code No. 323545) (Include Crown molding Stopper (L))
  3. Crown molding Stopper (L) (Code No. 323546)
  4. Crown molding Stopper (R) (Code No. 323547)

Wood and aluminum sash.


Make the following preparations before operating the power tool:

  • Installation


  • When the power tool is prepared for shipping, its main parts are secured by a locking pin. Move the handle slightly so that the locking pin can be disengaged.
  • Installing the dust bag, holder, stopper and vises (The holder and stopper are optional accessories.) Attach the dust bag and vise assembly as indicated in Fig. 1 and Fig. 2.


  • Make sure the power source is appropriate for the tool.
    WARNING: Never connect the power tool unless the available AC power source is of the same voltage as that specified on the nameplate of the tool. Never connect this power tool to a DC power source.
  • Make sure the trigger switch is turned OFF.
    WARNING: If the power cord is connected to the power source with the trigger switch turned ON the power tool will start suddenly and can cause a serious accident.
  • Check the saw blade for visible defects. Confirm that the saw blade is free of cracks or other visible damage.
  • Confirm that the saw blade is attached securely to the power tool. Using the supplied 17mm box wrench, tighten the bolt on the saw blade spindle to secure the saw blade. For details, see Fig. 44-a, Fig. 44-b, Fig. 44-c and Fig. 44-d in the section on “SAW BLADE MOUNTING AND DISMOUNTING”.
  • Check the lower guard for proper operation. Lower guard is designed to protect the operator from coming into contact with the saw blade during operation of the tool. Always check that the lower guard moves smoothly and covers the saw blade properly.
    WARNING: NEVER OPERATE THE POWER TOOL if the safety cover does not function smoothly.
  • Confirm the position of the spindle lock before using the tool. After installing the saw blade, confirm that the spindle lock has been returned to the retract position before using the power tool (see Fig. 44-b).
  • Check the Power Receptacle. To prevent overheating, accidental stopping or intermittent operation, confirm that the power cord plug fits properly in the electrical receptacle and does not fall out after it is inserted. Repair or replace the receptacle if it is faulty.
  • Confirm the tool’s power cord is not damaged. Repair or replace the power cord if an inspection indicates that it is damaged.



  • Trial Run
    After confirming that no one is standing behind, the power tool start and confirm that no operating abnormalities exist before attempting a cutting operation.
  • Inspect the rotating stability of the saw blade. For precise cutting, rotate the saw blade and check for deflection to confirm that the blade is not noticeably unstable; otherwise vibrations might occur and cause an accident.


  1. Oblique Angle
    Before the power tool is shipped from the factory, it is adjusted for 0°, right angle, left 45° bevel cutting angle and right 45° bevel cutting angle with the 8mm bolt (A), 8mm bolt (B) and the 8mm bolt (C). When changing the adjustment, change the height of the 8mm bolt (A), 8mm bolt (B) or the 8mm bolt (C) by turning them. When changing the bevel angle to the right 45°, pull the set pin on the direction shown in Fig. 8-b and incline the motor head to the right. When adjusting the motor head to 0°, always return the set pin to its initial position as shown in Fig. 8-a.
  2. Securing the Workpiece
  3. Installing the holders .. (Optional Accessory)
    • The holders help keep longer workpieces stable and in place during the cutting operation. (1) As indicated in Fig. 9, use a steel square for aligning the upper edge of the holders with the base surface. Loosen the 6mm wing nut. Turn a height adjustment bolt 6mm, and adjust the height of the holder. (2) After adjustment, firmly tighten the wing nut and fasten the holder with the 6mm wing bolt (optional accessory). If the length of Height Adjustment Bolt 6mm is insufficient, spread a thin plate beneath. Make sure the end of Height Adjustment Bolt 6mm does not protrude from the holder.






  • Laser radiation- Do not stare into beam.
  • Laser radiation on work table. Do not stare into beam. If your eye is exposed directly to the laser beam, it can be hurt.
  • Do not dismantle it.
  • Do not give strong impact to the laser marker (main body of tool); otherwise, the position of a laser line can go out of order, resulting in the damage of the laser marker as well as a shortened service life.
  • Keep the laser marker lit only during a cutting operation. Prolonged lighting of the laser marker can result in a shortened service life.
  • Use of controls or adjustments or performance of procedures other than those specified herein may result in hazardous radiation exposure.


Ink lining can be easily made on this tool to the laser marker. A switch lights up the laser marker. (Fig. 17) Turning on the laser marker switch while the digital display switch is on, light up the laser marker. (On the C12FDH, only the laser marker switch.) Depending upon your cutting choice, the laser line can be aligned with the left side of the cutting width (saw blade) or the ink line on the right side. The laser line is adjusted to the width of the saw blade at the time of factory shipment. Adjust the positions of the saw blade and the laser line taking the following steps to suit the use of your choice.

  • Light up the laser marker and make a groove of about 3/16″ (5mm) deep on the workpiece that is about 1-1/2″ (38mm) in height and 3-1/2″(89mm) in width. Hold the grooved workpiece by vise as it is and do not move it. (Fig. 18)
  • Then insert a 4mm hex. bar wrench in the 12 diameter hole on the side of the gear case, turn the hex. socket set screw to move the laser line. (If you turn the Hex. socket screw clockwise, the laser line will shift to the right and if you turn it counterclockwise, the laser line will shift to the left.) When you work with the ink line aligned with the left side of the saw blade, align the laser line with the left end of the groove. (Fig. 19) When you align it with the right side of the saw blade, align the laser line with the right side of the groove.
  • After adjusting the position of the laser line, draw a right-angle ink line on the workpiece and align the ink line with the laser line. When aligning the ink line, slide the workpiece little by little and secure it by vise at a position where the laser line overlaps with the ink line. Work on the grooving again and check the position of the laser line. If you wish to change the laser line’s position, make adjustments again following the steps from (1) to (3).




Move the turntable left and right with the side handle loosened and set it to the correct position.





  • As shown in Fig. 26 the width of the saw blade is the width of the cut. Therefore, slide the workpiece to the right (viewed from the operator’s position) when length b is desired, or to the left when length a is desired. If a laser marker is used, align the laser line with the left side of the saw blade, and then align the ink line with the laser line.
  • Once the saw blade reaches maximum speed, push the handle down carefully until the saw blade approaches the workpiece.
  • Once the saw blade contacts the workpiece, push the handle down gradually to cut into the workpiece.
  • After cutting the workpiece to the desired depth, turn the power tool OFF and let the saw blade stop completely before raising the handle from the workpiece to return it to the full retract position.
  1. Loosen the side handle and push the lever for angle stoppers. Then, adjust the turntable until the indicator aligns with desired setting on the miter scale (Fig. 27).
  2. Re-tighten the side handle to secure the turntable in the desired position.



  • Loosen the clamp lever and bevel the saw blade to the left or to the right. When tilting the motor head to the right pull the set pin towards the rear.
  • Adjust the bevel angle to the desired setting while watching the bevel angle scale and indicator, then secure the clamp lever.
  1. Grip the handle on the motor head and position it at the bevel angle you need. Temporarily tighten the clamp lever.
  2. Make fine adjustments to the bevel angle by gripping the handle and moving the knob (A).
  3. After adjusting to the desired angle, tighten the clamp lever and clamp the motor head.
  4. Compound Cutting Procedures
    Compound cutting can be performed by following the instructions in 4 and 5 above. For maximum dimensions for compound cutting, refer to “SPECIFICATIONS” table on page 9.

Crown Molding Cutting Procedures


The table below shows the miter angle and the bevel angle settings that are ideal for the two crown molding types.

For miter cut setting
If the turntable has been set to either of the angles described, move the turntable adjusting side handle a little to the right and left to stabilize the position and to properly align the miter angle scale and the tip of the indicator before the operation starts.
For bevel cut setting
Move handle on bevel section to the left and check that the position is stable and that the bevel angle scale and the tip of the indicator are properly aligned. Then tighten the clamp lever.




Cutting method of crown molding without tilting the saw blade


  • Crown molding Stopper (L) and (R) (optional accessories) allow easier cuts of crown molding without tilting the saw blade. Install them in the base both-sides side to be shown in Fig. 41- a. After inserting Tighten the 6mm wing bolts to secure the crown molding Stoppers. [Optional accessories used]
    • Crown molding Vise Ass’y (Include Crown molding Stopper (L))
    • Crown molding Stopper (L)
    • Crown molding Stopper (R)
  • The crown molding vise (B) (Optional accessory) can be mounted on either the left fence (Fence (B)) or the right fence (Fence (A)). It can unite with the slope of the crown molding and vice can be pressed down. Then turn the upper knob, as necessary, to securely attach the crown molding in position. To raise or lower the vise assembly, first loosen the 6mm knob bolt. After adjusting the height, firmly tighten the 6mm wing bolt; then turn the upper knob, as necessary, to securely attach the crown molding in position. (See Fig. 41-b)

Position crown molding with its WALL CONTACT EDGE against the guide fence and its CEILING CONTACT EDGE against the crown molding Stoppers as shown in Fig. 41-b. Adjust the crown molding Stoppers according to the size of the crown molding. Tighten the 6mm wing bolt to secure the crown molding Stoppers.

  • Cutting easily-deformed materials, such as aluminum sash Materials such as aluminum sash can easily deform when tightened too much in a vise assembly. This will cause inefficient cutting and possible overload of the motor. When cutting such materials, use a wood plate to protect the workpiece as shown in Fig. 42-a. Set the wood plate near the cutting section. When cutting aluminum materials, coat the saw blade with cutting oil (non-combustible) to achieve smooth cutting and a fine finish. In addition, in case of a U-shaped workpiece, use the wood plate as shown in Fig. 42-b to ensure stability in the lateral direction, and clamp it near the cutting section of the workpiece and tighten it using both the vise assembly and the clamp available in the market.



  • Mounting the saw blade (Fig. 44-a, Fig. 44-b, Fig. 44-c and Fig. 44-d)
    • Rotate the lower guard (plastic) to the top position.
    • Use the driver to loosen the 5mm screw fastening the spindle cover and then remove the spindle cover.
    • Press in spindle lock and loosen 10mm bolt with 17mm box wrench (standard accessory). Since the bolt is left-hand threaded, loosen by turning it to the right as shown in Fig. 44-c.
    • Remove the 10mm bolt and washer (B).
    • Lift the lower guard and mount the saw blade.
    • Thoroughly clean washer (A), (B) and the 10mm bolt, and install them onto the saw blade spindle.


  • Dismounting the saw blade Dismount the saw blade by reversing the mounting procedures described in paragraph 1 above. The saw blade can easily be removed after lifting the safety cover.



  • Inspecting the saw blade Always replace the saw blade immediately upon the first sign of deterioration or damage. A damaged saw blade can cause personal injury and a worn saw blade can cause ineffective operation and possible overload to the motor.
  • Inspecting the lever If the M8 hexagonal head bolts (2) are loose, align the sides of the fence and saw blade with the steel square. After adjusting the saw blade and fence to a ninety-degree angle, tighten the lever securing hexagonal head bolts (2).



  • Inspecting the carbon brushes (Fig. 46 and Fig. 47) The carbon brushes in the motor are expendable parts. If the carbon brushes become excessively worn, motor trouble might occur. Therefore, inspect the carbon brushes periodically and replace them when they have become worn to the wear limit line as shown in Fig. 46. Also, keep the carbon brushes clean so that they will slide smoothly within the brush holders. The carbon brushes can easily be removed after removal of the brush caps (see Fig. 47) with a slotted (minus) screwdriver.
  • About Handling the Motor (see Fig. 1) Winding of the motor is said to be the heart of this tool. Exercise utmost caution not to damage the winding by exposing it to wash oil or water.
  • Inspecting the screws Regularly inspect each component of the power tool for looseness. Re tighten screws on any loose part.
  • Inspecting the lower guard for proper operation Before each use of the tool, test the lower guard (see Fig. 7) to assure that it is in good condition and that it moves smoothly. Never use the tool unless the lower guard operates properly and it is in good mechanical condition.
  • Storage After operation of the tool has been completed, check that the following has been performed:
    • Trigger switch is in OFF position,
    • Power plug has been removed from the receptacle,
    • To prevent unauthorized operation of this tool, insert a padlock through the hole in the switch trigger. When the tool is not in use, keep it stored in a dry place out of the reach of children.
  • Replacement of Poly-V-Belt The power of the motor is transmitted to the saw blade by a Poly- V-Belt. When the Poly-V-Belt is broken or damaged, remove the pulley cover by loosening the three 5 mm screws (see Fig. 2) and replace the damaged one with the new one. When connecting the belt on pulleys, first connect 2 or 3 teeth of Poly-V-Belt to the grooves of the pulley (A) and pulley (B). Then turning the pulley (A) and pulley (B), connect all teeth of the belt to the pulleys.
  • Lubrication Lubricate the following sliding surfaces once a month to keep the power tool in good operating condition for a long time (see Fig. 1 and Fig. 2). Use of machine oil is recommended. Oil supply points:
    • Rotary portion of hinge
    • Rotary portion of vise assembly
  • Cleaning Periodically remove chips, dust and other waste material from the surface of the power tool, especially from the inside of the lower guard with a damp, soapy cloth. To avoid a malfunction of the motor, protect it from contact with oil or water. If the laser line becomes invisible due to chips and the like adhered onto the window of the laser marker’s light-emitting section, wipe and clean the window with a dry cloth or a soft cloth moistened with soapy water, etc.

SERVICE AND REPAIRS All quality power tools will eventually require servicing or replacement of parts because of wear from normal use. To assure that only authorized replacement parts will be used and that the double insulation system will be protected, all service (other than routine maintenance) must be performed by an AUTHORIZED HITACHI POWER TOOL REPAIR CENTER ONLY.

Issued by
Hitachi Koki Co., Ltd.
Shinagawa Intercity Tower A, 15-1, Konan 2-chome, Minato-ku, Tokyo 108-6020, Japan
Distributed by
Hitachi Koki U.S.A., Ltd.
3950 Steve Reynolds Blvd. Norcross, GA 30093
Hitachi Koki Canada Co.
6395 Kestrel Road Mississauga ON L5T 1Z5

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