Thread: Air hammer?

Ok, here's a quick video. It seemed like the switch/valve was getting screwed up by pressure in both hoses but I'm starting to think it was just out of air. Sometimes there would be no exhaust as though the switch/valve wasn't doing anything. But the regulator in the compressor always showed 80 lbs or so. Must be different from running low of volume.

So... Down to Princess Auto for a $600 air compressor?

https://vimeo.com/149817681

Nearly every one of these units I've seen operating...eventually ran the tank to empty. The one exception was attached to a largish screw compressor that never lacked for air...good luck.

Looking at an 80 gal 10 cfm shop tank. That's way overkill for anything else I would ever do in my garage. Will decide soon. Got this far, but that's got to double my cost!

I may have just done it...

https://vimeo.com/150215572
Well, it's looking more complete but still not working!

Actually, that video was taken before I fixed the die plates, which were interfering with the up stroke. Still not working though.

What I can't figure out is why t sometimes hisses air out the exhaust continuously but doesn't move, and other times doesn't vent any air at all. It's like the control valve gets equal pressure on both sides like I described and eventually just stops switching.

I may try changing the supply and exhaust again, but I think it is plumbed as it's supposed to be.

Originally Posted by Mike Blue

First off, I've never personally built an air hammer. I have a working hammer I'm happy with. But smiths talk about such things and this is what I remember.

The original Kinyon design and all the subsequent variations, are really air powered treadle hammers. One blow per push of air. They consume air so think about having enough air supply, e.g. a storage tank of some sort in-line because I've seen these things suck a compressor tank down to nothing in a short working time (shorter than the demonstrating smith wanted to get work done).

Discussion, criticisms of that kind of operating system arise from those of us who want to stay on the hammer while the steel is still hot.

https://www.youtube.com/watch?v=L5IIuhCbNto

The above video illustrates an air circuit that recuperates air. Aside of not wasting so much air compressed, it also allows the operator to "feather" the blows, increasing control over the power of each hit and the resultant cushion at the end of the downstroke pushes the tup back into recovery ready for the next stroke. It also means that the power of the downstroke is not beating the bottom seals out of the cylinder or the anvil and then reflecting back into the upper parts of the hammer. It allows for rebound upward. This is the primary type, maybe not an exact match, for the working parts of Beche, Nazel's, Chambersburg and other old style power hammers.

The bigger the falling weight, the bigger the anvil, so pay attention to any required mathematical relationships recommended for any power hammer about that ratio. The bigger the falling weight, the relative increase required in the moving parts as physics strictly applies. Every action means reactions at the same power. You don't want your hammer beating itself apart because of the absence of stout. I think this is why we are all card carrying members of Over-Engineers-R-Us.

Hopefully some of this will help.

Holy smokes, it pays to read and re-read. By the look of that video, the two-switch design does what I was talking about-- venting the 'off' side of the pilot circuit. I may go pick up a second switching valve and try this.

One thing isn't in the video though... Were those old hammer designs operated by throttling the incoming compressed air rather than the exhaust?

And why is that design supposed to be recuperating? There is no audio and I'm not sure I get it.

I will ask an engineer friend to look things over. I built the two-switch design and still it doesn't work!

Well, among other things, the integral valve bolts were coming loose, so who knows what was going on inside. I'll have to secure them with locktite.

I also drilled one hole in each of the pilot hoses to the valve using the smallest bit in my box (1/64" or something). When I removed the switches from their mounts, I could trigger the up and down actions and even reverse direction before the end of the travel. Not bad. Just need to dial in the mount locations. In fact, I am thinking about going back to the single switch design, with the switch placed just lower than half-way across the hammer's travel.

No engineering help yet, but anyway I hope to do creative work with friends rather than troubleshooting.