What detrimental effect can occur from over-tightening the gauge glass studs?

Over-tightening the gauge glass studs can lead to the cracking of the cone washers because excessive pressure can cause the washers to deform or fracture. Cone washers are designed to create a seal by conforming to the shapes they're compressed against. When the studs are tightened beyond their intended specifications, the cone washers cannot effectively handle the extra force, resulting in cracks. This compromises the integrity of the seal, potentially leading to leaks of steam or other fluids, which can pose safety hazards. Proper torque guidelines are crucial to ensure that the washer and gauge glass operate effectively and safely.