A.1 Principle
The saddle tree is supported at specified points, subjected to a load through the stirrup irons and the deflection is measured. The saddle tree is then examined for visible damage.
A.2 Apparatus
A.2.1 Stirrup bar, capable of withstanding a load of 10 x N.
A.2.2 Steel former, of 152 mm diameter.
A.2.3 Weights, or other means of loading the stirrups, to produce a downwards force of 8.9 x N ±0.5 x N.
NOTE This force is approximately equivalent to the downwards force generated by 2000 lb.
A.2.4 Stopwatch, or similar timing device.
A.2.5 Measuring instrument (e.g. a rule), capable of measuring in increments of 1 mm.
A.3 Procedure
A.3.1 Prepare the saddle tree as intended for use in a saddle. Fit with stirrup bar (A.2.1) and rivet on to withstand the test conditions using rivets conforming to 6.3.
A.3.2 Place the saddle tree on the steel former (A.2.2) and mark datum points (Y and Z) on the saddle tree, measuring 178 mm from the top (X) of the front arch down on either side of the front edge of the tree as shown in Figure A.1.
A.3.3 Load the saddle tree by gently adding weights (A.2.3) evenly to the stirrups, so that a total force of 8.9 x N ±0.5 x N is applied.
A.3.4 Allow the load to act for 300 s±5 s, as measured with the stopwatch (A.2.4), and measure the deflection at the datum points (see A.3.2), using the measuring instrument (A.2.5).
A.3.5 Remove the load and visually examine the saddle tree for damage.
A.4 Test report
The test report shall contain the following information:
B.1 Principle
A mass is dropped onto the saddle tree and then the permanent set is measured. The saddle tree is then examined for visible damage.
B.2 Apparatus
B.2.1 Steel disk, of 152 mm diameter and 50 mm thickness.
B.2.2 Fiat board, of dimensions 300 mm x 900 mm.
B.2.3 Weight, comprising a canvas sack and dry sand of mass
63.5 kg ±3 kg.
B.2.4 Lifting device, capable of lifting the weight (8.2.3) to a height of between 122 mm and 183 mm above the flat board (8.2.2).
B.2.5 Measuring instrument (e.g. a rule), capable of measuring in increments of 1 mm.
B.3 Procedure
B.3.1 Support the saddle tree on the steel disk (B.2.1). Place the flat board (8.2.2) on the saddle tree such that it is supported level on the saddle pommel overlapping by 150 mm ±10 mm.
B.3.2 Raise the weight (B.2.3) using the lifting device (8.2.4) to a height of 1.5 m ±0.3 m above the board. Drop the weight (8.2.3) onto the saddle tree end of the board ensuring that the whole weight is transmitted to the saddle tree.
B.3.3 Remove the saddle tree from the test equipment and measure the permanent set using the measuring instrument (B.2.5). Visually examine the saddle tree for damage.
B.3.4 Test report
The test report shall contain the following information:
a) the identity of the saddle tree;
b) the permanent set, expressed in millimetres;
c) whether or not the saddle tree was damaged; and