Woodworking lathes are designed to teach carpentry students in schools, universities and other educational institutions, and the machines home handymen often equipped with a tailstock with a non-rotating center. Maintaining them the end of the workpiece when the work is accompanied by the burning of wood in the zone of contact with the metal. The result is a vibration (especially in turning of long parts), which drastically reduces the quality of their treatment, and sometimes can lead to injury if the blank POPs out of the center.

Rotating radial ball bearings centres is significantly better for work, but they also have the disadvantage of low durability. Under the influence of constant axial loads is the relative displacement of the outer and inner rings of the bearing and, consequently, to intensive wear of the working grooves and the ball center goes down.
Such problems can be avoided by applying additional thrust bearing. But this alteration is quite complex and requires the presence of an appropriate bearing.
Offers more simple and not less effective solution: the installation of a suitable steel ball which the axial components of external loads between the cone and shank. Such improvement can be realized even with the power of the students themselves.
Improved tailstock center lathe woodworking machine STD-І20
An improved tailstock center lathe woodworking machine STD-І20:
1 — shank; 2 — transitional bushing; 3 — bearing 7000102; 4 — cone; 5 — bulb

At the end of the neck of the shank (centered) is the spherical recess under the steel ball to a depth equal to 1/3 its diameter. A similar recess is machined on the inner end of the cone. If necessary, when the diameter of the cylindrical neck of the shank is smaller than the inner diameter of the bearing, pressed in the neck of the adapter sleeve, the outer diameter of which is equal to the inner diameter of the bearing pre-pressed into the cone. The prepared spherical hollow filled with grease, fit a ball and cone bearing onto the shank.
In the improved construction the wear resistant ball and spherical surfaces occurs slightly and evenly, without exerting practically no influence on the efficiency of the center: it can perform its functions very long time without reducing the quality of machined parts.
teacher of technical creativity
Khakass state University,
g a b A C a n

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