Notes for owners · Industry playbooks
Hot forging, cold forging or machining from bar: telling the buyer honestly when forging pays
Whether a part should be hot forged, cold forged or turned from bar depends on yearly quantity and shape, and this post shows a forging shop how to work out the answer with the buyer.
The GullySales team · Updated 17 Oct 2026 · 6 min read
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A development engineer sends a drawing of a flanged shaft, says 400 pieces a year, and wants a forging rate. You can forge it. You also know a turning shop could make it from bar for less at that quantity. The honest answer rests on two things: how many pieces a year, and how much metal the bar route throws away. Forging pays when the die is paid back inside the part's confirmed volume and the shape wastes a lot of bar. Below that, say "turn it from bar" and show the arithmetic.
Three routes, three ways of paying
Machining from bar has no tooling. The buyer pays for bar by weight and for machine time, and every millimetre turned off a large diameter is steel bought and sold back as swarf.
Hot forging puts a die and a trimming tool up front. After that, each piece starts close to shape, so it needs less steel and less machining. The buyer waits for die sinking and sample approval before the first lot. And the buyer carries the die cost whether the order is 500 pieces or 50,000.
Cold forging needs heavier tooling and a bigger press, and is limited to smaller parts in steels that flow without heat. In return the part comes off near final size, so most of the machining disappears. It suits pins, ball studs, small gear blanks and special-head bolts made by the thousand, and little made by the hundred.
Which route to suggest, part by part
Use this as a first answer when a drawing arrives.
| The part in front of you | Route to suggest | Why | When the advice changes |
|---|---|---|---|
| Prototype, or first lots while the drawing is still moving | Bar | No die to scrap when the design changes | If the buyer's test has to be done on a forged part |
| Round part close to bar size, with small steps | Bar | Little metal to remove, so a die buys nothing | At very high quantities, where cold heading may cut the cycle time |
| Big flange or collar on a thin shank: flanged shafts, hubs, yokes | Hot forging | Turning from bar means buying the flange diameter for the whole length | When the confirmed quantity cannot pay back the die |
| Small part made by the thousand: pins, ball studs, small blanks | Cold forging | Near-final size, little machining, good finish | If the grade will not form cold, or volumes are in hundreds |
| Shock-loaded parts: cranks, connecting rods, lifting hooks, steering arms | Forging, as the drawing says | The buyer or the buyer's customer may require it | Never yours to change |
| Large part, few pieces: long shafts, heavy rings | Open-die forging or bar | No closed die is worth sinking | Whether bar of that diameter can be bought at all |
Working out the break-even with the buyer
The arithmetic fits in a WhatsApp message. Take the cost of the die and trimming tool. Divide it by the saving per piece, which is the bar-machined price minus the forged-and-machined price. The answer is the number of pieces at which forging starts to pay.
Then compare it with what the buyer has confirmed, not what the buyer hopes. Three outcomes, three answers:
- Break-even falls inside the first year's confirmed quantity: recommend forging.
- Break-even needs more than two years of the confirmed quantity, or outlasts the model: recommend bar now, and name the yearly figure at which you would switch.
- Break-even lands between the two: ask for the forecast in writing before either of you commits to a die.
"Confirmed" means a schedule, an open purchase order or a written forecast from the buyer's planner. A number said on the phone at the first meeting is a hope.
For example: a flanged shaft quoted from Gummidipoondi
Imagine a closed-die forging shop in Gummidipoondi, north of Chennai, asked by a compressor maker for a flanged drive shaft in EN19, 400 pieces a year. The figures are illustrative.
The shop quoted a die at ₹2.2 lakh and a forged piece price, and heard nothing. Three weeks later the engineer said, politely, that a turning shop in the city was machining the shaft from 90 mm bar. Nobody had compared the routes. So the engineer did it unaided, and the forger looked like a shop selling a die that was not needed.
On the forger's own numbers, a bar-machined shaft cost about ₹780 and a forged-and-machined one about ₹520. A saving of ₹260 a piece pays back ₹2.2 lakh after roughly 850 pieces. At 400 a year, that is more than two years. By the rule above, bar was the right answer.
So the owner rang the engineer and said exactly that, then sent a one-page note with both routes and the break-even. The forger gave up that order. When the compressor maker's larger model came with a heavier shaft and a forecast in the thousands, that drawing went to the forger first.
Put the comparison where the buyer will see it
Many buyers never ask which route is cheaper, assuming a forging shop will say forging. So say it before the question comes.
In the quotation, add a route note under the price:
Routes considered: drawing 4410, rev A, 400 pieces a year
Machined from bar no tooling about ₹780 a piece
Hot forged + machined die ₹2.2 lakh about ₹520 a piece
Break-even about 850 pieces
Advice at 400 a year machine from bar
Advice changes at 850 a year or more, confirmed in writing
A website page explaining the three routes tells an engineer there will be a straight answer. In a capability presentation, one slide about a part you advised against forging says more than three slides of hammers.
When to keep quiet about the bar route
Some drawings settle the question. If the buyer or the buyer's customer has specified a forging, a cheaper bar route is not yours to offer. Raising it only shows you did not read the drawing.
If you have no turning capacity and no shop you would vouch for, do not send the buyer hunting. Say that the quantity does not suit forging yet, and ask the buyer to call when the forecast grows.
And if a trader wants a rate per kilogram, skip the analysis. The trader is collecting numbers, and your route note will reach the next shop on the list.
Add a route note to the next drawing
When the next enquiry arrives with a yearly quantity, work out the bar price and the break-even before you price the die. Put both in the quotation. Add the quantity at which your advice would change. The rest of the forger's selling job is on the forging and metal forming page. If you want the note and the capability slide written around your own presses, tell us what you need.
