BS ISO 16287:2021 pdf download.Plain bearings — Thermoplastic bushes — Dimensions and tolerances.
8 Testing 8.1 General The dimensions of the bush shall be tested in the conditioned state (see also the Note in Clause 6). 8.2 Outside diameter, D o a) Check the outside bush diameter with two ring gauges. The GO ring corresponds to the maximum D o size limit and the NO GO ring to the minimum D o size limit according to Tables 1 to 4 or supplier specification for special thermoplastic compounds. b) Measure the outside diameter in free condition, determined as the arithmetic mean of at least two measurements (see ISO 12301). 8.3 Inside diameter, D i a) Check the inside bush diameter with two ring gauges. Insert the bush successively into two gauging rings, one corresponding to the maximum size limit and the other to the minimum size limit of the housing tolerance class H7. The inside bush diameter shall not exceed the bottom limit of the specified tolerance class according to Table 5, when inserted into the gauging ring having the minimum housing tolerance limit. The inside bush diameter shall not exceed the upper limit of the specified tolerance class when inserted into the gauging ring having the maximum housing tolerance limit. The inside maximum and minimum bush diameter shall be checked with a GO and NO GO plug gauge or measured with a 3-point measuring instrument. b) Check the inside bush diameter with one ring gauge, in accordance with ISO 3547-2, test C for wrapped bushes Press the bush into a ring gauge, the size of which is made up of D o and the rounded average value of the tolerance class H7. The inside diameter of the bush when it is pressed into the ring gauge D i,ch shall be checked with a GO and NO GO plug gauge or measured with a 3-point measuring instrument. The width of the gauging ring shall be greater than the width of the bush. There are tolerance differences between checking the inside diameter of the bush in two ring gauges corresponding to the H7 limit sizes [see 8.3, a)] and checking the inside bush diameter in one ring gauge with the average value of H7 [see 8.3, b)]. There are further tolerance differences between gauging and measuring the inside bush diameter. Therefore, checking details shall be subject to agreement between the supplier and the purchaser. 9 Assembling A cylindrical or flange bush should be assembled into its housing with the aid of a stepped mandrel, preferably made from case-hardened mild steel. A 45° lead-in chamfer should be machined in the housing to assist assembly. For flanged bushes, the minimum chamfer shall be r max × 45° (to allow for the radius behind the flange). The bush, mandrel and housing shall be correctly aligned during assembly. Mandrel and chamfer dimensions should be as shown in Figure 3.\BS ISO 16287 pdf download.