Do SDS drills lose their oomph as they get older?

IME all SDS systems recommend periodic greasing in this way. If you don't, you get fretting wear which will eventually cause the bit to seize in the chuck.

Crankshaft bearings wear too.

Although motor brush wear usually manifests as very sluggish or intermittent movement for a relatively short time, followed by failure. Rather than steady degradation which is more consistent with mechanical wear (or perhaps hardening of rubber seals).

Diamonds burn. Nice CO2 out of them.

And the owners :-)

yes, but use the black stuff that comes with a CV boot repair kit. Ordinary grease will rot the outer rubber nose.

Its usually a swash bearing style drive, the arm on which moves a cylinder or plunger back and fourth, and that is pneumatically coupled to a free sliding hammer.

So I suppose some wear on that interface could make the pneumatic couple weaker with age. Having said that, by SDS is probably at least 15 years old, and I have not noticed any drop off in performance (other than when I had to replace the armature that is!)

Really? I'd be surprised if that wasn't nitrile. Certainly mine copes fine with ordinary mineral oil grease.

Hmm, perhaps I'm either imagining it then, or I've found some harder walls than before. I might also have been spoiled because I borrowed a nearly-new Makita for a short time.

It possibly depends on the internal design of the drill as well. Some of the more basic ones need a continuous supply of internal grease it seems, whereas the better ones only need the occasional bit of grease on the back of the bit.

The manual for mine says to use any, ordinary, lithium grease.

SteveW

My Bosch drills came with a sachet of silicon grease.

Bill