Insane Hydraulics
Bold and audacious blog about fluid power
If you are a mechanic with some experience - you've done it. I have done it. All of my friends have done it. We all have done it! I am talking about mounting a tight shaft coupling with the aid of a few hammer taps. It never feels right, and yet - you look to your left, then to your right - and if no one is looking - Whack! - and the coupling is in place!
But there's a difference between a couple of measured taps and full-blown sledgehammering. Here's what happened to a brand-new Rexroth A6VM107 when the shaft coupling was hammered in - the over-enthusiastic strikes caused the center pin to deform the retainer plate, and when the motor began rotating - the "pinch point" created enough metal shavings to gradually destroy first the shaft, then the bearings, and eventually the case-side of the barrel bores.
So, if you need to tap-mount a shaft coupling on a hydraulic pump or a motor, and you can't do it with a plastic mallet and your non-dominant hand - look for a way to "un-tighten it" rather than reach for a tool that requires two hands to be handled.