Gauge Tolerance Band
I. Gauge Tolerance Band Items
(1) Errors can also be generated during the manufacture of gauges, so it is necessary to specify manufacturing tolerances.
(2) The "go gauge" of a working gauge may wear out when passing through a workpiece, so a wear limit needs to be specified; the "no-go gauge" of a working gauge wears less and does not require a wear limit specification.
(3) Smooth limit gauges control the limit dimensions of workpieces.
II. Diagram of the Gauge Tolerance Band
1. Tolerance band for working gauges
(a) The tolerance band for the "no-go gauge" of a working gauge starts from the minimum material size of the workpiece and is distributed within the workpiece's tolerance band;
(b) The tolerance band for the "go gauge" of a working gauge is symmetrical around the Z value, and its wear limit coincides with the maximum material size of the workpiece.
2. Tolerance band for checking gauges
(a) Classification of checking gauges:
"Check-Go-Go" (TT): Checking gauge for the "go gauge" used to inspect shafts. Its function is to prevent the go gauge dimension from being too small, and it should pass through the checked gauge during inspection.
"Check-Go-Wear" (TS): Checking gauge for the wear limit of the "go gauge" used to inspect shafts. Its function is to prevent the go gauge from exceeding the wear limit dimension, and if it passes through the checked gauge during inspection, it indicates that it has reached the wear limit.
"Check-No-Go-Go" (ZT): Checking gauge for the "no-go gauge" used to inspect shafts. Its function is to prevent the no-go gauge dimension from being too small, and it should pass through the checked gauge during inspection.
(b) Distribution of the tolerance band for checking gauges:
The TT tolerance band is distributed within the tolerance band of the go gauge for shafts starting from the lower deviation of the go gauge;
The TS tolerance band is distributed within the tolerance band of the go gauge for shafts starting from the wear limit of the go gauge;
The ZT tolerance band is distributed within the tolerance band of the no-go gauge for shafts starting from the lower deviation of the no-go gauge.
3. National standards stipulate that the form and position errors of working gauges should be within the range of the manufacturing tolerance of the working gauges, and their tolerance is 50% of the gauge manufacturing tolerance.
4. The manufacturing tolerance of the checking gauge is 50% of the manufacturing tolerance of the shaft gauge being checked, and its shape tolerance should be within the range of the checking gauge manufacturing tolerance.
5. The tolerance band of the working gauge is located within the range of the workpiece's limit dimensions, and the tolerance band of the checking gauge is located within the tolerance band of the gauge being checked, thus ensuring that the workpiece meets national standard requirements but reduces the manufacturing tolerance of the workpiece.