John Larson Posted March 29, 2012 Share Posted March 29, 2012 I used a test today to satisfy myself that my Iron Kiss hammers work best on a throttled exhaust as opposed to a throttled inflow of pressurized air. You can do the same test on your exhaust throttled machine. Your results may differ from mine. With the inlet air hand valve turned off, I blocked the treadle so that it was down. Then I started to turn on air inflow using the hand valve as a throttle. And, of course, the hammer reciprocated. All the variations of the exercise showed me that air-inflow throttling does not produce as crisp a hammer blow as air-outflow throttling does. Try it and see what you think. [i use very responsive Nugget 500 spool valves with air-actuation and spring return.] Quote Link to comment Share on other sites More sharing options...
ptree Posted March 29, 2012 Share Posted March 29, 2012 John, in industry, air cylinder flow is controlled on the exhaust almost exclusively in every machine I can think of. The probelm with air being compressable is that if you control in, then all the exhaust from the other side runs away, and you build a little pressure in the fed side, the pistion overcomes stiction and moves, the pressure drops as the volume increases and then the cycle starts anew. I would agree with you to controlling the exhaust Hydraulic cylinders ARE NEVER controlled exhaust. If you put the rated pressure in the blind side, the rod side being controlled you get a pressure multiplication that can blow seals at the least. Bigger the rod the bigger the issue. In air not a problem as the air is easily copmpressed. Quote Link to comment Share on other sites More sharing options...
mike-hr Posted March 30, 2012 Share Posted March 30, 2012 John, could you firm up on this check a bit? You want us to block the treadle down, and then turn on the air? I don't know if I want to whang on my dies dry just to see if they start whanging or not....Is there a stopwatch involved? What are we looking for? Quote Link to comment Share on other sites More sharing options...
John Larson Posted March 30, 2012 Author Share Posted March 30, 2012 Just open the hand valve slightly at first as if just barely pressing the treadle under usual conditions. If your dies bang together then they bang together under your usual conditions, and I doubt you have your machine set to do that. So there should be no problem. If you want to play with hot metal, just get somebody to assist. If there is little difference, then you'll sense it, just as if there is substantial difference. No stop watch work needed. You can be the judge. Quote Link to comment Share on other sites More sharing options...
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