(A) Seamless steel pipe size accuracy
In order to determine the position of the shaft,it is usually required for its dimensional accuracy (IT5 ~ IT7). The accuracyof the journal size of the assembly drive is generally low (IT6 ~ IT9).

(B) Seamless steel pipe geometry accuracy
The geometric shape accuracy of the shaft partsrefers mainly to the roundness, the cylindrical degree, etc. of the journal,outer cone, Mohs cone, etc., and should be limited to the tolerance range. 40Crseamless steel pipe with high accuracy requirements of the inner and outercircular surface, the drawings should be marked on the allowable deviation.

(C) Seamless steel pipe position accuracy
The positional accuracy requirements of the shaftparts are determined primarily by the position and function of the shaft in themachine. It is usually necessary to ensure that the journal of the drive bodyis required to coax the support journal, otherwise it will affect thetransmission accuracy of the transmission (gear, etc.) and produce noise. Theaxis of normal accuracy, the radial runout of the support shaft with respect tothe support journal is generally 0.01 to 0.03 mm, and the high precision shaft(e.g., the main shaft) is usually 0.001 to 0.005 mm.

(D) Seamless steel pipe surface roughness
In general, the surface roughness of the shaftdiameter is Ra2.5 ~ 0.63μm, and the surface roughness of the supporting shaftdiameter is 40.63 ~ 0.16μm with the 40Cr seamless steel tube bearing.