Found a load chart from 1972 for a Manitowoc 3900

Ngl I was digging through some old files in the shop last Thursday and pulled out a load chart for a Manitowoc 3900 from 1972. The safe working loads are way lower than what we run on modern cranes of the same size class. Crazy to see how much the engineering has changed in 50 years. Has anyone else ever compared old load charts to new ones for the same basic boom length?

3 comments

3 Comments

sethhernandez6d ago

Bet you the wire rope ratings were totally different too, old stuff was built for way less abuse than what we push through now. It's wild how much headroom they built into those old charts compared to the computer-designed limits today.

the_jordan6d ago

Wait, you're telling me grandpa's old crane was actually 10x stronger than my new one and he just didn't know it? That's like finding out your beater truck from 1985 secretly had a V8 under the hood while your new F-150 is running on a lawnmower engine. I swear the numbers on those old charts might as well have been pulled out of a hat after three beers. 'Looks like 5 tons, feels like 10, let's call it 3 to be safe.' Now they've got some intern with a laptop shaving off every last pound because the computer says it'll hold.

webb.ben6d ago

Had a buddy who used to run an old P&H from the 50s, thing had a plate that said 15 tons but he'd pick 25 all day without breaking a sweat. @the_jordan would get a kick out of that one, same way old wire rope manuals had safety factors of like 7 or 8 while new stuff's cut down to 3. Makes you wonder if all that "progress" is really an upgrade or just us getting comfortable with less margin.