---
title: "Forging hammers, presses, advantages and limits"
subject: "Workshop Technology"
chapter: 9
key: "semester_2/workshop_technology:forging-hammers-presses"
source: https://www.bctengineer.com/q/semester_2/workshop_technology/forging-hammers-presses
site: BCT Engineering
---

# Forging hammers, presses, advantages and limits

Workshop Technology · Chapter 9: Forging Practice

- Asked in: year not given, 6 marks
- Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14
- Page: https://www.bctengineer.com/q/semester_2/workshop_technology/forging-hammers-presses
- Whole chapter: https://www.bctengineer.com/md/semester_2/workshop_technology/chapter-9

## Question

Differentiate between forging hammers and forging presses. State the advantages and limitations of forging.

## Short answer

Forging hammers deliver a high‑velocity impact, deforming mainly surface layers; presses slowly squeezze, deforming the full depth. Advantages: grain flow gives high strength and toughness, eliminates voids, good surface in closed dies. Limitations: costly dies, difficult complex shapes, scale and poor dimension in hot forgig, not for brittle metals.

## Answer

#### Forging hammers and presses
| Forging hammer | Forging press |
|---|---|
| Energy is delivered as a high-velocity blow (impact) | Squeezing action with slow, steady pressure |
| Types: board, drop, steam/air, power hammer | Types: mechanical (crank, eccentric), hydraulic, screw |
| Deformation mostly on the surface layers | Deformation reaches the full depth of the job |
| Noise, vibration; needs heavy foundation | Quiet, smooth operation |
| Dies wear quickly; lower accuracy | Better dimensional accuracy; less draft needed |
| Capacity in kg of falling weight | Capacity in tonnes of force |
| Cheaper, used for small and medium work | Costly; suits large and heavy forgings |

Drop hammer: ram falls under gravity (board or steam-lifted) on the heated billet in a die. Power hammer: steam or compressed air drives the ram down faster.

#### Advantages of forging
- Grain flow follows the shape, giving high strength, toughness and fatigue resistance.
- Removes internal voids and blowholes; gives dense structure.
- Good for small and large parts, produces a good surface and accuracy in closed dies.
- Material saving over machining from solid.

#### Limitations
- High cost of dies and equipment for small batches.
- Complex shapes with deep cavities and undercuts are difficult.
- Hot forging gives scale and poor surface and dimensional accuracy.
- Not suitable for brittle metals; needs heating and skilled operation; some safety risk.

## Check yourself

The answer's key points as multiple-choice questions, with the correct option and why.

1. How does the action of a forging hammer differ from a press?
   A. Hammer gives slow steady squeeze; press gives impact
   B. Both give impact but at different speeds
   C. Hammer gives high-velocity impact; press gives slow, steady squeezing
   D. Hammer works cold; press works hot only
   Answer: C. Hammers deliver energy as an impact blow, presses apply slow squeezing pressure. (Key point: Hammer vs press action)

2. Which is true about the depth of deformation?
   A. Hammer deformation reaches the full depth; press mainly the surface
   B. Press deformation reaches the full depth of the job; hammer mostly the surface layers
   C. Both deform only the surface
   D. Both deform equally throughout
   Answer: B. The slow squeeze of a press penetrates the full section, whereas hammer blows mostly work the surface. (Key point: Depth of deformation)

3. Which is an advantage of forging?
   A. Cheap tooling for small batches
   B. Easy production of deep cavities and undercuts
   C. Suitable for brittle metals
   D. Grain flow follows the shape and voids are removed, giving strength and toughness
   Answer: D. Forging refines structure, removes blowholes and aligns grain with the shape. (Key point: Advantages of forging)

4. Which is a limitation of forging?
   A. High die and equipment cost for small batches
   B. Poor fatigue resistance
   C. Internal blowholes are created
   D. Cannot be done on large parts
   Answer: A. Dies and equipment are costly, so small batches are uneconomical. (Key point: Limitations of forging)

## Related in other subjects

- [Casting versus forging design considerations](https://www.bctengineer.com/question.md?key=semester_7%2Fmachine_design_ii%3Acasting-forging-design-differences) — Machine Design II, chapter 3
- [Noise vs interference and their limitations](https://www.bctengineer.com/question.md?key=semester_6%2Fcommunication_systems%3Anoise-interference-limitations) — Communication Systems, chapter 1
- [Race condition; optimal page replacement limits](https://www.bctengineer.com/question.md?key=semester_6%2Foperating_system%3Arace-condition-optimal-limitation) — Operating System, chapter 3
- [Calorimeter wattmeter and single bridge bolometer limits](https://www.bctengineer.com/question.md?key=semester_7%2Frf_and_microwave_engineering%3Acalorimeter-wattmeter-bolometer-limits) — RF and Microwave Engineering, chapter 8