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locking taper angle

locking taper angle

locking taper angle

Hi all,

what is the standard angle for a locking taper? Does it depend on mating materials?

A taper machined onto two mating parts such that when the parts are mated the frictional forces are so great will not rotate or move with respect to one another. No clamping forces are required to keep the parts joined, but considerable force is required to separate the items. This is an extremely rigid and accurate method of joining arbors and spindles.


RE: locking taper angle

I have always used 7 degrees as a rule of thumb. This is for steel on steel. It must change for different materials but I'm not sure by how much.

RE: locking taper angle

Look in Machinery's Hdbk is the section on "Standard Tapers"
Brown & Sharpe & Morse are locking [~2-3deg], whereas "Self releasing" tapers are 16 deg

RE: locking taper angle

the taper angle measured in radians should be less the coeficient of friction between the mating surfaces.

RE: locking taper angle

The way I remember it,is that approximately 7 degrees (Semi-Cone Angle) is the greatest angle that will "stick".

Morse, Brown and Sharpe, Jarno tapers, etc, are mostly less than 4 degrees a side, See "Machinery's Handbook"

Machine tool spindle tapers that use drawbars or other clamping devices tend to have much higher angles.

RE: locking taper angle

I have just completed the design of a Rope Socket, used in the wireline industry of the oilfield.  My taper angle was exactly 14 degrees, 7 degrees per side; this was stated above.

She works like a dream.  The semi-cone angle of 7 degrees is ideal for reasons discussed above.

Kenneth J Hueston, PEng
Sturni-Hueston Engineering Inc
Edmonton, Alberta Canada

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