McMaster-Carr logo
    Enter e-mail addresses in the fields below
    Message
    Cancel
    Comments
    E-mail address (if you would like a response)
    51 Products

    Granite Surface Plates
    3D CAD models available

    Image of Product. Front orientation. Surface Plates. Granite Surface Plates, Rectangular Plate.
    Image of Product. Front orientation. Surface Plates. Granite Surface Plates, Rectangular Plate with Two Ledges.

    Rectangular Plate

    Rectangular Plate with Two Ledges

    With flatness tolerances thinner than a strand of hair, these plates give you the flattest possible surface for accurate measurements. They’re typically used as a reference plane to inspect finished products and calibrate precision measuring tools, such as height gauges and dial indicators. Unlike metal plates, these granite plates won’t rust or interfere with nearby electronics. They also won’t warp when temperatures fluctuate. To maintain their flatness and finish, rotate plates regularly and apply granite cleaner (not included) to remove particles without leaving a residue.
    Also Available: Other plate sizes. Please order 2245A999 and specify grade, length, width, thickness, and with or without ledges.
    Laboratory-Grade AA Plate—Best for precision inspections and quality-control work in calibration labs. These plates have the tightest flatness tolerance for the highest level of accuracy.
    Inspection-Grade A Plate—Your go-to for general inspections and quality-control work. These plates are slightly less precise than grade AA plates with double the flatness tolerance.
    Toolroom-Grade B Plate—Suitable for checking routine measurements throughout a shop. These plates are the least precise with four times the flatness tolerance of grade AA plates.
    Black—Harder and denser than red plates to handle heavier loads, such as large bearings and other machined parts.
    Red—Resist wear better than black plates to last up to five times longer. With a higher percentage of quartz, you can slide parts across these plates without worrying about nicks and scratches.
    Rectangular Plate with Two Ledges—Choose these plates if you need to mount fixtures and instruments with a clamp.
    Surface Plate Covers—Prevent dust and debris from accumulating on plates when you’re not using them.
    Surface Plate Stands—Attach to plates at three support points to keep them from sagging and warping, as specified in Fed. Spec. GGG-P-463-c. The welded steel construction offers greater strength, durability, and stability than economical alternatives such as block and wedge systems.
    Rectangular Plate
    Rectangular Plate
    with Two Ledges
    Surface
    Plate Covers
    Flatness
    Tolerance
    Lg.
    Wd.
    Ht.
    Specs. Met
    Certificate Type
    Wt.,
    lb.
    Each
    Wt.,
    lb.
    Each
    Each
    Laboratory-Grade AA Plate
     
    Black
    0.00005"6"4"2"ASME B89.3.7, Fed. Spec. GGG-P-463, ISO 10012Accuracy Certificate Traceable to NIST7000000000000000____00__00
    0.00005"12"8"2"ASME B89.3.7, Fed. Spec. GGG-P-463, ISO 10012Accuracy Certificate Traceable to NIST280000000000000____000000000000000000
    0.00005"18"12"4"ASME B89.3.7, Fed. Spec. GGG-P-463, ISO 10012Accuracy Certificate Traceable to NIST93000000000000083000000000000000000000000000
    0.000075"24"18"4"ASME B89.3.7, Fed. Spec. GGG-P-463, ISO 10012Accuracy Certificate Traceable to NIST1850000000000000175000000000000000000000000000
    0.0001"36"24"6"ASME B89.3.7, Fed. Spec. GGG-P-463, ISO 10012Accuracy Certificate Traceable to NIST601000000000000000____0000000000000000
    0.0002"48"36"6"ASME B89.3.7, Fed. Spec. GGG-P-463, ISO 10012Accuracy Certificate Traceable to NIST1,203000000000000000____0000000000000000
     
    Red
    0.00005"18"12"4"ASME B89.3.7, Fed. Spec. GGG-P-463Accuracy Certificate Traceable to NIST840000000000000000____000000000000000
    0.000075"24"18"4"ASME B89.3.7, Fed. Spec. GGG-P-463Accuracy Certificate Traceable to NIST1680000000000000000____0000000000000000
     
    Inspection-Grade A Plate
     
    Black
    0.0001"6"4"2"ASME B89.3.7, Fed. Spec. GGG-P-463, ISO 10012Accuracy Certificate Traceable to NIST700000000000000____00__00
    0.0001"12"8"2"ASME B89.3.7, Fed. Spec. GGG-P-463, ISO 10012Accuracy Certificate Traceable to NIST280000000000000____00000000000000000
    0.0001"18"12"4"ASME B89.3.7, Fed. Spec. GGG-P-463, ISO 10012Accuracy Certificate Traceable to NIST9300000000000008300000000000000000000000000
    0.00015"24"18"4"ASME B89.3.7, Fed. Spec. GGG-P-463, ISO 10012Accuracy Certificate Traceable to NIST1850000000000000175000000000000000000000000000
    0.0002"36"24"6"ASME B89.3.7, Fed. Spec. GGG-P-463, ISO 10012Accuracy Certificate Traceable to NIST55500000000000000053000000000000000000000000000000
    0.0004"48"36"6"ASME B89.3.7, Fed. Spec. GGG-P-463, ISO 10012Accuracy Certificate Traceable to NIST1,1100000000000000001,06300000000000000000000000000000
     
    Red
    0.0001"12"8"2"ASME B89.3.7, Fed. Spec. GGG-P-463Accuracy Certificate Traceable to NIST2000000000000000____00000000000000000
     
    Toolroom-Grade B Plate
     
    Black
    0.0002"6"4"2"ASME B89.3.7, Fed. Spec. GGG-P-463, ISO 10012Accuracy Certificate Traceable to NIST700000000000000____00__00
    0.0002"12"8"2"ASME B89.3.7, Fed. Spec. GGG-P-463, ISO 10012Accuracy Certificate Traceable to NIST210000000000000____00000000000000000
    0.0002"18"12"3"ASME B89.3.7, Fed. Spec. GGG-P-463, ISO 10012Accuracy Certificate Traceable to NIST7000000000000006600000000000000000000000000
    0.0003"24"18"3"ASME B89.3.7, Fed. Spec. GGG-P-463, ISO 10012Accuracy Certificate Traceable to NIST1390000000000000130000000000000000000000000000
    0.0004"36"24"4"ASME B89.3.7, Fed. Spec. GGG-P-463, ISO 10012Accuracy Certificate Traceable to NIST3700000000000000357000000000000000000000000000
    0.0008"48"36"6"ASME B89.3.7, Fed. Spec. GGG-P-463, ISO 10012Accuracy Certificate Traceable to NIST1,203000000000000000____0000000000000000
     

    Granite Surface Plate Stands
    3D CAD models available

    Secure granite surface plates on these stands to ensure a flat surface for accurate measurements. To keep plates from sagging and warping, stands attach to plates at three support points, as specified in Fed. Spec. GGG-P-463c. The welded steel construction offers greater strength, durability, and stability than economical alternatives such as block and wedge systems.
    Mobile—Conduct measuring and inspecting tasks anywhere in your facility. With steel plate casters and hard, durable wheels, these stands support the same capacities as their stationary counterparts. Turn the adjustable screws on top of the stand to level the plate on uneven floors.
    Stationary—Create a permanent setup for routine measurements and inspections. Twist the mounts at the bottom of each leg to level the plate, even on uneven floors.
    For
    Plate
    For
    Rectangular Plates
    For Rectangular Plates
    with Two Ledges
    Lg.
    Wd.
    Ht.
    Load Cap.,
    lb.
    Ht.
    Material
    Each
    Each
    Mobile
    Image of Product. Front orientation. Mobile. Mobile.
    18"12"3", 4"40036"Painted Steel000000000000000000000000000000
    24"18"3", 4"50036"Painted Steel0000000000000000000000000000
    36"24"4", 6"1,20036"Painted Steel00000000000000000000000000000000
    48"36"6"2,40036"Painted Steel00000000000000000000000000000000
     
    Stationary
    Image of Product. Front orientation. Surface Plate Stands. Stationary.
    18"12"3", 4"40036"Painted Steel0000000000000000000000000000
    24"18"3", 4"50036"Painted Steel0000000000000000000000000000
    36"24"4", 6"1,20036"Painted Steel0000000000000000000000000000
    48"36"6"2,40036"Painted Steel0000000000000000000000000000
     
    back to top