Dowel Shear Tests

Test to confirm shear strength of each pin/sleeve size.

Test method – Retain pin in a three block assembly, center block designed to move downward through assembly, side support blocks retain pin/sleeve assembly in a horizontal position. Recorded tonnage will show double the amount due to shear condition on both sides of cutting block. All blocks are A2 tool steel heat treated to Rockwell 62-65 RC. Pins are random samples from inventory. (Note – the slot in the sleeve was positioned horizontal during test).
Size
EX-250
EX-375
EX-500
EX-625
EX-750
EX-1000
Sample 1 Pounds
14,000
31,400
56,500
88,250
126,500
220,000
Sample 2 Pounds
13,850
32,800
57,250
95,250
126,500
220,150

Vibration Tests

Test of eight each of the EX-375 and EX-500

                                                    Test was conducted by Bell Aerosystems Company

A pair of each pins was installed in each of the test unit assemblies.

The test units contained the following materials

TEST UNIT

MATING BLOCK MATERIALS
No. 1 Cast Iron Cast Iron
No. 2 Cast Iron Tool Steel
No. 3 Machined Steel Tool Steel
No. 4 Machined Steel Machined Steel

RESULTS

Each unit was vibrated a total of 140 minutes. Dimensional checks made during and at the conclusion of the test indicated that none of the expanding dowel pins had moved from their installed positions. Removal of the pins from the test blocks was easily accomplished using the pin extractors provided.

Apparatus and Method

The four test block assemblies were bolted to the head of an MB Electronics Model C25A vibration machine to provide vibration along the longitudinal axis of the dowel pins. Vibration input was monitored by an MB Type 124 pickup bolted to the vibrating head adjacent to the test units. The vibration schedule consisted of seven constant octave frequency sweeps from 5 to 500 to 5 cps in 20 minutes. Between 5 and 40 cps, the applied vibration was maintained at 0.35 inches double amplitude and from 40 to 500 cps at a constant peak acceleration of ± 25 g’s.

Prior to, during, and after the test, the position of each dowel pin relative to the test block face was determined with a depth micrometer.