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The Kracken 4B starting to come together but has control issues


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The ram repair, swapping compressor pistons, shimming the guides, foundation, dies.... Pretty much done... Now that the thing moves under its own power I am trying to dial it in. If you have run a air hammer you know that the stroke of the ram is relatively short and it goes higher and lower while cycling in that short range... Well for some reason I am getting full strokes of like a foot rather than 4" no matter where I am in the cycle.... Its got to be a valve issue but I dont know what to look for. I have pulled the bottom valve, checked the timing marks under the check valve.... Not sure where to go from here.... As it is there is no fine control... you come down to the work and you cant tap tap tap.. just hit hard... Any ideas?

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No, It means I would like to get the hammer running after spending 15 thousand bucks trying to bring it to life, especially since it cant come to my home shop... I am trying to figure out what I am doing and making plans assuming that this spring I will have to move... If things improve I'll stay in the shop

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Good Morning Larry,

My understanding of the control valve is that when the pedal is released there is no air (or very limited) to the top of the working cylinder. Most of the air is sent to the lower part of the working ram to hold the die & ram up. Is there some way to adjust the control valve so les air goes to the top of the ram. Maybe an extra lever with a dump valve?

Is there a check valve that could be not closing properly?

Good Luck

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My 2b only hit very hard and had no short stroke when i got it. I had to rebuild the valves. Air slipping around the valves gave it no control. I rebuilt the valves like Bob Bergman shows in his video, by brazing up with silicone bronze. I actually rebuilt mine 3 times. First two times i did nothing to the sleaves. Last time i sent the sleaves out to be cylintricly ground. That made all the difference. After remachining the valves to the freshly ground sleaves it works like it should. I had a german guy in PA do the cylintric grinding. HANNER INDUSTRIES $900 for the 2 sleaves. Hope that helps

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  • 4 weeks later...

Larry.... Does your Nazel have the original muffler and muffler cone? If not, and the current parts restrict the air movement differently than the original parts, it would affect the behavior of the ram. I don't know if it would fix your problem, but if your current setup is not original, you might try making a change to allow a litlle more air to be moved through the muffler.

I do know, for sure, that if the air restriction is increased, the result is that the ram moves up more aggressively, so it makes sense to me that decreasing the air restriction through the muffler will produce the opposite effect.

If you try something like this, please post the results.

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Larry

I just did a little experiment on my 1B. I put pressure (pushed up) on the valve stem (bypass valve) while I was pressing down a bit on the treadle. This would simulate having a stronger spring.... It moved the stroke down further, and seemed to shorten it.

Give this a try.

I can't try it on my larger hammer (3B) this morning because I burned up the coil on my magnetic starter a couple days ago and haven't replaced it yet....

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Update.... I wired a temporary switch for my 3B and played with it. I didn't get the same results as with the 1B, so I guess it's back to the drawing board. I still think that too much air may be getting into the lower end though. Gotta study that valving and air flow some more.

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Slowing it down by 10% or so with a VFD should give it some manners. I have worked on a couple of un-usable hammers, that are lovely once slowed down a smidge.


John..... Thanks for the "changing the speed" nudge... I had thought about doing that, but didn't put it on my list. I don't have a VFD, but.... for an experiment, I can hook the hammer up to an old military generator I have and slow the motor down. I know I have read somewhere (can't put my hands on the source document right now) that the speed (BPM) on these hammers can be varied by 25%. If I understand the electrical aspects correctly, I should be able to take the speed of the generator down till it is running at 50 cycles (as opposed to 60 cycles). The hammer motor, although it doesn't have a 50HZ rating on it, should be able to run at that HZ for a while without causing problems (any other opinion out there?). I think the generator motor rpm is proportionate to the cycles generated. If I've done the math correctly, I should be able to drop the hammer BPM to 150 (from 180), assuming the speed of the motor will drop with the lower HZ source.
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This is a mechanical (air getting someplace it's not suppose to or not getting it someplace its needed) issue. Slowing the hammer down will not change the nature of the blow which is the issue. I should not be getting 15" of ram cycle when trying to maintain light squeezing taps. I have replaced the pinion effectively reducing the speed by 20%, no change in blow reciprocating length, still full travel under minimum treadle

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Slowing the hammer down can change the nature of the blow, it stops the air 'fighting' or 'catching up with itself'. , though not in the case of your hammer!

Are there any escape holes in the compressor piston that have been plugged up ? excess air can lead to long elastic light blows.

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So in the nazel where and how does the air come from that limits the upward stroke? I pulled the cushion tower and ram today to check the ball checks (which are working). The cushion plug is sloppy, maybe .025 when it should be .002 but during light treadle the ram should not be engaging the cushion plug anyway (I am building a new one regardless)

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Larry.... I'm tending to agree with you. The source of the missing or errant air is what's in question.

I wanted to try slowing my hammer down to see if it would help because, after John posted his comment (and I planned to take the BPM down as low as 150 BPM), I remembered my hammer is running faster than the factory 180 BPM. Not much, only at 192 BPM, but maybe enough to cause issues for this feature.

I gingerly drove my bobcat over part of my lawn today to move the generator. I wired the 3B motor to it and did the experiment I spoke of earlier. Results were not conclusive. I couldn't slow the motor down as much as I had hoped to. The cycle gauge only went down to 55 (I didn't want to peg it downward). If things worked as I had expected, slowing down the motor till the cycles gauge read 56 should have reduced the speed of the hammer to the factory 180 BPM. The hammer did seem to have slowed down, but when I tried to count the cycles using a stop watch, it was difficult to confirm it. In any case, the hammer still did not perform better with regards to the short, light blows.

Keep in mind that.... earlier, when I had put a restriction on the top of the muffler (closer to what I believe the top opening of the muffler tower should be), it did work better, but still not the way I expect it should (based upon Larry's and others experience.

Larry.... Do you have Mark Krause's Operating Principles handbook? I wish it were more detailed, but it does have air flow diagrams at idle, half treadle down, full treadle down and clamp. The "treadle half way down" diagram was why I thought the bypass spring might be involved.


I will still continue to look for an original cone and muffler tower, or fabricate them with as close to original tolerances as I can. I am totally convinced those tolerances play a significant part in the air management.

My hammer is belt driven with a custom steel pulley. I believe I can have the pulley turned down (it's solid) more to get the hammer running at 180 BPM. I'm not sure, at all, it will help with the light blow issue.

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