Standard Machine Tapers

Note: The information contained here is for referance only of common standards and and may not accurately reflect actual product dimensions.

Please check the product details or ask if any dimension is critical

  • Standard Morse Taper Dimensions

    morse-taper2

    MORSE
    TAPER
    No.    		 A

    mm

    		 B

    mm

    		 C

    mm

    		 D

    mm

    		 E

    mm

    		 TAPER
    per mm
    on dia.
    1 12.065 62.0 65.5 5.2 5 0.04988
    2 17.780 75.0 80.0 6.3 6 0.04995
    3 23.825 94.0 99.0 7.9 7 0.05020
    4 31.267 117.5 124.0 11.9 8 0.05194
    5 44.399 149.5 156.0 15.9 10 0.05263

  • Standard R8 Taper Dimensions

    r8_taper

  • This taper was designed by Bridgeport Machines Inc. for use in their milling machines. It is used with a drawbar extending up through the spindle to the top of the machine to prevent the collet from falling from the spindle when lateral forces are encountered. The collet, which is inserted into the taper, has a precision hole in one end for holding a cutting tool and is threaded for a drawbar on other end. They are also keyed (see image) to prevent rotation during insertion and removal. However, cutting torques are transferred through friction at the taper, not through the key. The drawbar thread is typically 7/16″-20tpi (UNF).

    The cutting tool is placed in the collet, the collet placed into the taper, and the drawbar is tightened into the top of the collet from above the spindle. The collet has a groove to engage a key in the spindle to keep the collet from spinning inside the taper and to aid in the installation and removal of the collet. The angle of the cone is typically 16 degrees and 51 minutes (i.e. 16.85 degrees) with an OD of 1.25″ (source, Bridgeport Manufacturer).

  • Standard Jacobs Taper Dimensions

    jacobs_taper

    The Jacobs Taper (abbreviated JT) is commonly used to secure drill press chucks to an arbor.

    Taper Small End Big End Length
    mm inch mm inch mm inch
    0 5.80 0.2284 6.35 0.2500 11.11 0.4375
    1 8.47 0.3334 9.75 0.3840 16.67 0.6563
    2 12.39 0.4876 14.20 0.5590 22.23 0.8750
    2 Short 12.39 0.4876 13.94 0.5488 19.05 0.7500
    3 18.95 0.7461 20.60 0.8110 30.96 1.2188
    4 26.34 1.0372 28.55 1.1240 42.07 1.6563
    5 33.43 1.3161 35.89 1.4130 47.63 1.8750
    6 15.85 0.6241 17.17 0.6760 25.40 1.0000
    33 14.23 0.5604 15.85 0.6240 25.40 1.0000