Page 107 - CITS - Fitter - Trade Theory

FITTER - CITS

- Shaft Basis System:
In the shaft basis system, the size of the shaft is considered as the basis for establishing the fit. The tolerance
zone for the shaft is fixed, while the hole is designed to accommodate the shaft within this tolerance zone. This
means that the hole’s dimensions can vary within a specified range to accept the shaft.
- Key points:
• The shaft is held to a specified size, and the tolerance is applied to the hole.

• The hole can have various sizes within its tolerance range, but it must accept the shaft.
• The fit is determined by the relationship between the size of the hole and the size of the shaft.
- Applications:
• This system is often used in applications where the shaft is more critical, such as gears, pulleys, or other
components where precise shaft dimensions are essential for proper functionality.

92

CITS : CG & M - Fitter - Lesson 14