Astro_Al Posted June 2, 2009 Share Posted June 2, 2009 Hi folks, I'm on the cusp of starting to build my kinyon-ish style pneumatic power hammer. I've been investigating the options for the control system. Since there is no specific thread on the relative merits of different control approaches, I thought I'd start one. The only power hammer I have experience of is a modern Sahinler, which I found very easy to use and control - something like that would suit me just fine. I was almost settled on the Coleman approach to controls, but I'm reading comments and having doubts. What would people recommend / suggest, especially those who have used different home built hammers and can comment on the relative performance. I'd appreciate any input. Is the extra complexity of the Coleman worth it? What would you choose and why? Cheers, Al. Quote Link to comment Share on other sites More sharing options...
PeterDE4 Posted June 2, 2009 Share Posted June 2, 2009 My only experience with pneumatic power hammers is a Kinyon style hammer I built myself. I used the modified controls designed by some guys at the Alabama Forge Council, which adds a second regulator. Using their system, the control is excellent. I set the main regulator at 100 psi and the secondary at 50-60 psi. Depending on how far you push down the pedal, you can get a light tap-tap-tap or a heavy bam-bam-bam. I've seen videos of the Coleman system, and it is impressive, but as you say, it is complex as well. Quote Link to comment Share on other sites More sharing options...
JNewman Posted June 7, 2009 Share Posted June 7, 2009 (edited) I built my hammer with the origional Kinyon plumbing and have had no problem with control, I can tap very lightly or hit hard. The one thing that I think is very important is to use faily large control valves and hoses. All my hose is 1/2" and I think the ports on my control valve are 1/2" as well. Make your pilot valve easily adjustable, I adjust mine up if I am using tall tooling under the hammer or if I want to hit a lot of light fast blows or down if you are just drawing out stock or want slower heavy blows. The one change I made to the control circuit after a few years is a change that John Larson came up with and then mentioned on keenjunk. John is the designer and builder of the Iron Kiss hammer and has spent a lot of time testing various control circuits. He was very generous with sharing many of the results of his testing over on Keenjunk. The change made causes the ram to return to the top of the stroke when you take your foot off the treadle, this is particularly useful if you use a lot of tooling under the hammer. This change involves adding an extra pilot valve in the air supply for the pilot valve. The new pilot valve is actuated by the treadle so that when your foot is off the treadle there is no air supplied to the pilot valve that is triggered by the ram. A small leak in the exhaust is then introduced so that when your foot is off the treadle the air in the top of the cylinder leaks out and the ram rises to the top of its stroke. Because there is no air to the pilot valve it does not trip the control valve. I believe John has come up with a new even better control system for his hammers but they involve a custom made exhaust valve that John builds for his hammers. Edited June 8, 2009 by JNewman Quote Link to comment Share on other sites More sharing options...
Astro_Al Posted June 12, 2009 Author Share Posted June 12, 2009 Hi, thanks very much indeed for the information. I see keenjunk is offline. Do you have any more technical info / diagrams or anything for that added extra? I'm off to buy powerhammer materials in the morning... Cheers, Al. Quote Link to comment Share on other sites More sharing options...
John Larson Posted June 21, 2009 Share Posted June 21, 2009 Keenjunk was superceded by forgemagic.com. Also farwestforge.com is similar and technically superior, though sparsely populated. Glenn made this site, probably about the same time as Keenjunk was retired. This site is much superior technically, but the style is topical rather than gossipy. More like a library and technical support center than forgemagic. Keenjunk archives are available if you want to do the effort. The plumbing scheme mentioned by JNewman is simply a way to turn the air to the roller valve on-off as the treadle is depressed. Quote Link to comment Share on other sites More sharing options...
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