Guides / Cost

When Hot Forging Beats Turning a Brass Part From Solid

September 21, 2026

Turning a chunky brass fitting from solid bar throws away most of the metal as chips. On a heavy part in real volume, that waste is the largest single line in the quote, and there is a process that removes it.

The two routes

Turning from bar. Take a bar at least as big as the largest diameter on the part, and cut away everything that is not the part. Simple, no tooling cost, excellent tolerances, high material waste on bulky shapes.

Hot forging then machining. Heat a cut billet to around 700 to 800 degrees Celsius, squeeze it in a die to a near net shape, trim the flash, then machine only the sealing faces, threads and tight features. Low material waste, good grain flow, and a die to pay for first.

The decision between them is arithmetic, and it turns on three numbers.

The three numbers

1. How much metal you throw away. Take the bar volume you would need and subtract the finished part volume. On a slender shaft that difference is small and forging saves little. On a valve body with a large hex and a thin waist, you might be cutting away two thirds of the bar.

Remember what that metal costs. Brass is 60 to 70 percent copper and bought by weight, and chips sell back well below bar price. See what drives the cost of a machined brass fitting.

2. How much cycle time you save. Removing metal takes time. If the forging arrives at near net shape, the machining operation might be a fraction of what it was, which frees machine hours as well as metal.

3. The die cost. A one off charge, paid once, amortised over every part that comes off it. The question is how many parts it takes to repay the material and time saved.

The rough crossover

The usual planning figure is somewhere around 5,000 pieces per year for a bulky part. Below that, turning from bar normally wins. Above it, forging usually does.

That is a starting point, not a rule. The crossover moves earlier when:

• The part is bulky relative to its largest diameter
• The design is stable and will not be revised
• The annual volume repeats for several years
• Machine time in the region is expensive

It moves later, or disappears, when:

• The part is slender, so little material is wasted anyway
• Volumes are uncertain or the design may change
• The part needs tight tolerance over most of its surface
• The alloy does not forge well

Which alloys forge

C377 forging brass, CuZn39Pb2, CW612N. The classic. Its alpha-beta structure becomes highly plastic at forging temperature. Machinability 80 after forging, which is still very good.

C37700. The close relative, common on American drawings for the same job.

CW617N, C385 and the architectural brasses. Forge well, which is why so much door and window hardware is forged brass.

DZR grades such as CW602N. Forge and machine well, which is exactly why they are the European water fitting standard. See dezincification resistant brass.

C260 cartridge brass. Single phase alpha. It cold forms beautifully and does not hot forge well. Different tool for a different job, see C360 or C260.

Lead-free grades. Some forge. Availability and shop experience are both thinner, so ask specifically rather than assuming.

What changes on the drawing

A part that moves from bar to forging is not the same drawing with a different note. Four things change.

Draft angles. The part has to come out of the die, so vertical walls become slightly tapered. Typically one to three degrees. Either allow it or machine it away.

Flash line. Where the die halves meet, a thin fin forms and gets trimmed. That line stays visible unless machined off. Decide where it is allowed to be.

Radii. Sharp internal corners are hard on a die and shorten its life. Generous radii are cheaper and last longer.

Tolerances. As forged, plan on roughly plus or minus 0.05 mm for a small part. Anything tighter is a machined feature and should be drawn as one. See tolerances and surface finish on brass parts.

The grain flow bonus

There is a mechanical benefit that rarely gets counted.

In a bar turned part, the grain runs along the bar regardless of the part shape, so a thread cut across the grain is cutting through it. In a forging, the grain flows around the shape of the die, following the contours of the part.

For a pressure fitting or anything loaded in bending, that continuous grain flow gives better fatigue behaviour than the same geometry cut from bar. It is not usually the reason to forge, but it is worth knowing when your part is safety related.

How to ask for it

The mistake is asking for a forging quote when what you want is the cheapest route.

Better: send the drawing, the annual quantity and the repeat horizon, and ask the shops to quote the route they would choose. A shop that forges will tell you the crossover on your specific part. A shop that only turns will quote turning, which is also useful information.

If the answer comes back that the volume does not justify a die, you have learned something for free, and the turning quote is still the one you needed.

Got a bulky brass part with real annual volume? Send the drawing, put the yearly quantity in the quantity field and mention that the design is stable. It changes which shops we match it to.

Frequently asked questions

Keep reading

• What Drives the Cost of a Machined Brass Fitting
• Why Your Brass Quote Expires and What To Do About It