The use of Pneumatic Hammers for building pans is the most significant step forward in pan production in the last 20 years
Credit must go to Denis Martin of Rhythmical Steel for this discovery.
Before you start...
Air hammers are not cheap. To get a pneumatic rig going you're going to need to be prepared to invest a significant amount of money - likely in the range of several thousand dollars.
You'll need to acquire the following:
- An industrial compressor - about $ 950.00 or more.
- Regulator, Oiler, Hoses, Water-trap, connectors etc
- A foot pedal (I'll make a post for plans for it - about $ 200.00)
- The air hammer(s). You'll likely need at least two @ $ 500.00 each
- Tips for the hammers (Sinking, Shaping, Smoothing). Getting these professionally made might cost $ 250.00 or more per tip.
The Compressor
Right upfront - the 30 gallon "home workshop" style units are not up to the task of powering an air hammer. Unless you're in the mood to burn one out, don't even try. You're going to have to invest in an industrial grade compressor.
The one I use is a 60 gallon, 220V, 3.7HP unit. It can allegedly provide 11.5 CFM (Cubic Feet per Minute) at 90 PSI. The Max PSI is around 155, and the tank is rated to 175 PSI. I run my air tools at a max pressure of 120 PSI.
It can run one sinking air hammer comfortably. It can just about run two of them simultaneously, but it works pretty hard to do so.
I've installed a box fan to continuously blow air over the heads when I'm using it. The built in "fan" that's attached to the compressor head only runs when the compressor is charging, so it is not effective at keeping the heads cool. I've had my compressor for about 10 years now and it still going pretty well, and I attribute part of that to the box fan.
I also installed a drain HOSE at the bottom of the tank so that I can easily drain the compressor when I'm done using it. On a humid summer day in Ohio the tank will fill with about a 1/4 liter of water every day. If you have to crawl under the tank to mess around with the tiny stop-cock on the bottom of the tank, you're going to be less inclined to drain it daily.
Replace the oil regularly. I don't replace mine as often as I should, but that's no excuse for you.
Buy a spare power switch for the compressor. When the on-off switch dies halfway through sinking a pan, you're going to be glad you had one on hand. I find the design of the switches is pretty substandard and they die fairly often. I replace mine about once a year because the contacts wear out.
Keep a fire extinguisher handy. And be sure to turn the unit off when you're not using it and shut the main valve. If an air line blows when you're not around, the compressor will likely run to the point of thermal failure.
Don't forget: you'll also need hoses, a regulator, a water trap, an inline oiler, and other miscellaneous air tool stuff.
Foot Pedal
To properly and easily control the speed and pressure of the air hammer, I strongly recommend building a foot pedal. They're not hard to make, and I have instructions in a separate post.
Hammer Tips
I use three main tips on my air hammers - a Sinking Tip, a Smoothing Tip, and a Shaping Tip. I developed a system whereby I can switch these around without too much difficulty.
I turned all these pieces on a lathe. They're made from S7 tool steel; I had originally intended to heat treat them to harden them but it's been 10 years and they're working fine so.....
The end of most hammer shafts have a taper on it (usually an 802 taper or a Morse 2 Taper). Some hammers have a thread cut into the end of the shaft so that the original tip can be secured with a machine screw. Usually when you purchase a hammer you will have to remove the rubber butt that comes pre-mounted. I've found it useful to remove the rubber with a knife and then use a blow-torch to heat the metal mounting plate to "persuade" it off the shaft.
I have found it useful to weld the receiver onto the shaft of the hammer. The downside is that if I ever need to replace anything on the hammer shaft (e.g. the bushings) its going to be PIA. But I can say that you'll likely want to weld them too after the first time the receiver comes off the shaft while you're hammering, and the shaft then punches a hole in the pan on the next stroke.
A few builders I know have simply welded the desired tip onto the mounting plate that comes with the hammer and it works fine if you have more than one hammer.
The Air Hammers
The names and measurements of Air Hammers vary widely. It seems there is very little standardization in the Air Hammer world (familiar, right?) It also seems that one manufacturer (Jet) recently changed all their naming conventions, or at least kept the names but changed the hammers. I bought a few of their tools and ended up sending them back because the tool didn't match the stroke specs that were listed.
What you'll see below are the hammers that I have tried and like; at the end there is a photo of a hammer that I really don't like and suggest that you avoid.
I used 4 different air hammers in my setup. I used to have two and would change the tips on them depending on what task I was doing, but it started to become tedious to do that, so I ended up shelling out to buy a few more.
There's a trade off in air hammers between speed and power. A hammer with a large throw (the distance between extended and retracted) is going to exert a lot of force on the surface of the pan. A large throw means a lower number of strokes per minute, but there's more force on each stroke.
On the other hand, a hammer with a very high number of strokes per minute is going to exert way less force per stroke; so it won't be much good for sinking, but it will be great for smoothing the pan out.
Bear in mind that some hammer manufacturers publish "throw" data that simply doesn't match what the actual extension is for the hammer shaft. I can't explain why this is, and have not been able to find a satisfactory explanation.
You'll find brand names such as "Texas Pneumatic", "Michigan Pneumatic", "Cleveland Air Tools" out there. They all seem to have their own numbering system with the exception of the 2BA model.
A Good First Hammer - the 2-BA
If you're starting out and are looking to get just a single hammer, I would recommend the Model 2-BA. It seems to be made by a few different manufacturers. It's a pretty decent compromise between speed and power, and can be used for sinking, shaping, and prepping. You're not going to set any sinking speed records with this hammer but it will get the job done.
This hammer is sometimes called an S2BA or a BD-2BA. The critical part is the 2BA; it seems to indicate a fairly standard sized hammer across various manufacturers.
Sinking Hammers - 6" or 7" throw
For a sinking hammer you're going to want a slower stroke with a lot more power. I use a Michigan Pneumatic Model No 14 for sinking. I have not seen another one for sale anywhere.
This hammer runs with a faster stroke than the Texas 8-4" (the next model describe) but it seems to also produce more power.
The hammer below is a large Smoothing Hammer that would also work for sinking. I don't have an interchangeable tip for it as I only use this one for smoothing. The reason I use such a large hammer is that when I do the initial smoothing of the sink shape, there is a significant amount of movement required in the material close to the rim. A smaller hammer is not capable of moving the steel in a timely manner.
This is a Texas Pneumatic Tools Model TX 8-4" It has about a 6" throw.
Shaping & Prep Hammer - 2" Throw
The first hammer I purchased (pictured below) was this "Airpower Pneumatic Tool Product" from "Cleveland Ohio". It has a pretty short 2" throw and therefore high number of strokes per minute. It is a fantastic tool for shaping and prepping a drum. It's not great for sinking and it wasn't long after I bought this that I went looking for a heavier duty sinking hammer.
I wish I could find another one of these hammers but I have not been successful in my search.
Hammers to Avoid
The D3 hammer that is available at a very attractive price is (in my opinion) really not very useful for pan building.
The stroke is too long for the size of the hammer, and it sits somewhere between a sinking and shaping hammer but without the power and without the speed. I tried everything to get this to work since it is about 1/5th the price of anything else. People who've visited my shop and tried to use it have all put it down after about 5 minutes.
I can't speak about the other D series hammers since I haven't tried them, but based on the experience with the one I have I'm not inclined to do so.
One other drawback with these hammers is that they seem to have very non-standard fittings on them and it is a bit of a mission to connect them to a compressor.
