Quijote
Full Access Member
Unless they are torqued to yield, or have built-in thread-locker, one should be able to reuse them. As for the torque value, the threads clearly have not changed, so unless the surface area of the built-in washer is smaller, the torque should not have changed. But maybe they have realized they don't need to be torqued as much and backed off the spec.
Anecdote: As a younger engineer I was assigned the design of the largest machine we had ever made. I was worried about anything failing (huge piece of capital equipment would be trashed) so for the drivetrain I followed the Gates design guide to a t. Given the stiffness and size of the toothed belts, the tensions required by their calculations were pretty huge. So I then had to design the components and the housing to take those loads without failing or even deflecting too much. We bought sonic tension meters to make sure every belt was properly tensioned. Worried about how high the range was, and extrapolating from smaller machines on which we had decades of field experience, I told manufacturing to go to the lower end of the wide tension range. Still, it was really hard to hit that tension consistently. Finally, we get one of their application engineers to come on site and their response was that those values were too high and could probably be cut in half. *eyeroll* Of course, it was too late to redesign the drivetrain for less beefy and less expensive components, so we were stuck with those.
The point of the story is that perhaps the initial calculations could have informed the initial torque, but maybe over the years they realized it was overkill and possibly too difficult to service, causing premature, wear, etc.
Anecdote: As a younger engineer I was assigned the design of the largest machine we had ever made. I was worried about anything failing (huge piece of capital equipment would be trashed) so for the drivetrain I followed the Gates design guide to a t. Given the stiffness and size of the toothed belts, the tensions required by their calculations were pretty huge. So I then had to design the components and the housing to take those loads without failing or even deflecting too much. We bought sonic tension meters to make sure every belt was properly tensioned. Worried about how high the range was, and extrapolating from smaller machines on which we had decades of field experience, I told manufacturing to go to the lower end of the wide tension range. Still, it was really hard to hit that tension consistently. Finally, we get one of their application engineers to come on site and their response was that those values were too high and could probably be cut in half. *eyeroll* Of course, it was too late to redesign the drivetrain for less beefy and less expensive components, so we were stuck with those.
The point of the story is that perhaps the initial calculations could have informed the initial torque, but maybe over the years they realized it was overkill and possibly too difficult to service, causing premature, wear, etc.
