Quick answer: Work out the biggest hole you punch in the thickest plate you use. Multiply hole diameter by plate thickness by 80. That is the tonnage you need for mild steel. Then add some headroom.
Most small fab shops are well served by a 45 to 65-ton machine. Shops punching heavy plate all day, or running two operators, should look at 95 tons and up.
An ironworker is the most useful machine in a fab shop that nobody outside the trade has heard of. One machine punches holes, shears flat bar, cuts angle, notches and, with the right tooling, bends. It replaces a drill press, a band saw and a lot of grinding for the work it covers.
Here is how to pick the right one without paying for tonnage you will never use, or running out of it on the first big job.
1. Tonnage: the punching math
Ironworkers are rated by the tonnage at the punch station, and punching is where you hit the limit first. The standard formula for mild steel (about 60,000 psi) is:
Tons needed = hole diameter (in) × material thickness (in) × 80
| Job | Math | Tons needed |
|---|---|---|
| 1/2" hole in 1/4" plate | 0.5 × 0.25 × 80 | 10 tons |
| 3/4" hole in 3/8" plate | 0.75 × 0.375 × 80 | 22.5 tons |
| 1" hole in 1/2" plate | 1 × 0.5 × 80 | 40 tons |
| 1-1/16" hole in 3/4" plate | 1.0625 × 0.75 × 80 | about 64 tons |
Stainless needs roughly 1.5 times that number, and aluminum roughly half. As a rule, you also cannot punch a hole smaller in diameter than the plate is thick, whatever the machine's tonnage.
Rule of thumb: size the machine to your heaviest regular job, then add about 20%. Running an ironworker at its limit every day wears tooling and the machine faster.
2. Stations: what the machine actually does
A typical hydraulic ironworker has four or five work stations:
- Punch station. Round, square and oblong holes in plate, flat bar and angle.
- Flat bar shear. Cuts flat bar and plate strips square and clean, with no saw kerf and no heat.
- Angle shear. Cuts angle iron in one stroke. Some machines also mitre it.
- Notcher. Takes a rectangular or V notch out of angle and plate, so you can fold or fit frames.
- Section shear. Cuts round and square solid bar.
Before you buy, write down the five things you cut most often and check each one against the machine's capacity chart. Flat bar width and angle size are the two numbers that limit shops most often.
3. Single operator vs dual operator
On a single-operator machine, one person runs one station at a time. That is fine for most small and mid-size shops.
A dual-operator ironworker has two independent cylinders and controls, so two people can work two stations at once. A good example is the Baileigh SW-95, a 95-ton, 5-station machine. If you have the labor and the volume, it can nearly double output from one footprint.
4. Power: single phase or three phase
Check your panel before you shop. Many ironworkers are three-phase only, but there are good single-phase options:
- The JET JIW-45T runs on 115V single phase.
- Baileigh builds 1-phase versions of its 44, 50 and 62-ton machines.
- Edwards offers 230V single phase on its 55, 65 and 100-ton machines.
If you are unsure what your shop has, read our shop power guide before you order.
5. Edwards PowerLink: one power source, more machines
Edwards ironworkers with PowerLink can send their hydraulic power out to separate Edwards attachments. These include the HAT series tube and pipe benders, shop presses and the 25-ton dual-station ironworker.
If you plan to add bending or pressing later, PowerLink lets you buy the tool without buying another motor and pump. Edwards also sells most of those attachments with their own portable power unit, if you would rather run them separately.
6. Tooling: budget for it up front
The machine is only half the purchase. Punches and dies wear, and you will want several sizes. Edwards sells productivity packs with a full punch and die set and a back gauge, and several Edwards ironworkers come as packages with a brake attachment or coper notcher already included. Pricing a package is usually cheaper than adding the pieces later.
7. Manual ironworkers
If you only cut and punch light flat bar now and then, a manual ironworker like the Baileigh SW-22M does the job without hydraulics or power. It is not a production machine, but it is a big step up from a hacksaw and a drill.
Quick picks
Not sure which tonnage fits your work? Tell us the material, the thickest plate and the biggest hole you punch. Chat with us on the site or call (888) 990-8016 and we will give you a straight answer.