I'm attending SIU in Carbondale, and we have one of the new model 50 Kg Kuhn hammers. It's been out of commission for the past three or four years due to the fact that it was losing power, and the rhythm was slowing down. It was losing power to the point that while running, the ram would just stop cycling and sit on the bottom die. It also knocked loudly while running, something that was not coming from slipping belts. All of these problems got worse as the hammer was used. When I finally looked into it (and I was the 4th guy to do so), I noticed that the rod was loose in its bushings on the compressor cylinder (the source of the knocking).
That prompted me to take apart the rear (compressor) cylinder to check on the piston rings. Upon taking the cylinder apart, my first surprise was that everything was bone dry and covered with a black powder mixed with specks of metal. My next (horrible) discovery was that the rings had entirely disintegrated, and that both the piston and cylinder tube had been heavily galled, which was where all those shiny little specks of metal had come from. It looked as though someone had taken a chisel and incised the entire circumference with rather heavy grooves.
Now from what I can tell, there was never an oil line that ran to the compressor cylinder. The only oil line on it goes to the ram cylinder. The dealer at Centaur Forge that I've been dealing with says that the rear (compressor) cylinder does not require any oil due to the materials the rings are made of. Note that this cylinder is an aftermarket component that Kuhn buys ready to go from another manufacturer. However, it seems that a lack of lubrication in the cylinder was the source of the failure. Nevertheless, we are awaiting the arrival of a brand new compressor cylinder to get the hammer back up and running. Once its installed, we are thinking about running an oil line to the compressor cylinder to keep this problem from happening again.
Your hammer may very well be starting to experience the same symptoms as the one at school. I've heard that other smiths who have these newer models have also experienced similar problems. Check it out ASAP before any major damager gets done!
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