Tapers – sizes

International tapers

All of the international tapers have the same angle for the taper. This is 3 1/2 inches per foot. This taper is such that a male and female taper will not lock together – it is essential to use a drawbar to hold them together.


fig an Int 30 taper male taper

760 tabs on female international taper

fig an Int 30 female taper

The common sizes of these tapers are 30, 40 and 50.

The easiest point to measure on these is the wide end of the taper. This also happens to be easily accessible on both the male and female taper.

Taper number        width at wide point of taper

30                                       1 1/4 in

40                                       1 3/4 in

50                                       2 3/4 in


Morse tapers – sizes

Perhaps the most common taper is the Morse taper. Its strange characteristic is that though the angle of the taper for each size appear to be the same, They all very slightly different. The angle, in every case, is small enough to make a pair of tapers self locking. Though this commonly works on a drilling machine it is not regarded as self locking on a milling machine and a drawbar should always be used when milling.

fig male Morse taper

fig female Morse taper

The most common sizes are 1, 2, 3 and 4.

The taper for each of these is shown along with the widest width of the taper

taper no                    taper in per foot                widest width of taper

1                                   .59858                             0.475

2                                0.59941                             0.700

3                                 0.60235                            0.938

4                                0.62326                             1.231

This means that when a lathe is being set up to make a taper and this setting is made using an existing taper, then this taper must be the same size as the one being made.



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