It's amazing how they had a whole stamped metal frame in there to stiffen it up. Like what was the design criteria that made them think they needed all that steel? Violent cavemen users?
They may have expected typists coming over from typewriters to hammer on it for 8 hours a day, or to give them a similar feel to ease the transition and limit complaints.
IBM was a typewriter company and their keyboards reflected that for quite awhile - keys you could “tell” you pressed, machines that could take a beating.
Also most keyboards from the era were “similar” since the switches were somewhat of a standard. It wasn’t until the PC market took off and went nuts that cost cutting and other developments began - especially in the portable/laptop area.
It wasn't a "frame" really, it was just a single sheet of stamped steel in a curved shape.
The Model M wasn't nearly as impressive, or durable, as the Model F that preceded it and which was included with the IBM PC. Those keyboards had metal housings, unlike the plastic housings of the Model M.
> If you've never used a Model M, they're beasts.
I jokingly call it the preppers keyboard as it can double as a clubbing weapon when SHTF.