Understanding What’s in a Railroad Spike
Before diving into forging with railroad spikes, it’s essential to understand their composition and purpose. These spikes are engineered to secure railway tracks firmly in place, enduring heavy loads and constant stress. Their material makeup is tailored to balance strength, toughness, and ductility, making them suitable for various forging applications.
Key Properties of Railroad Spikes
A railroad spike must possess specific properties to perform its role effectively. It needs to be strong enough to hold tracks securely yet malleable enough to tolerate bending without cracking. The balance between hardness and ductility is crucial; overly hard spikes tend to become brittle and prone to shattering under impact, while too soft spikes lack the necessary strength.
Standards Governing Railroad Spike Material
The ASTM A65-07 standard outlines the requirements for railroad spikes, categorizing them into three primary types based on their material composition:
- Category 1: Low carbon steel, primarily mild steel with minimal carbon content.
- Category 2: Higher carbon steel, which offers increased hardness and strength.
- Category 3: Structural steel conforming to A36 specifications, suitable for heavy-duty applications.
Material Composition and Variations
Typically, railroad spikes are made from carbon steels with approximately 0.4% carbon content, similar to grade 1045 steel, making them tough and capable of handling substantial loads. Low carbon spikes are akin to mild steel, offering excellent ductility but limited hardness. Some spikes may incorporate alloying elements like copper or manganese to enhance malleability and reduce the risk of cracking. Over the decades, especially since the 1970s, manufacturers have shifted from low carbon to higher carbon spikes to improve durability and performance.
Identifying and Testing Railroad Spikes
Given the variability in manufacturing, especially with older or recycled spikes, testing becomes vital. While heat treating and heat testing can provide some insights, the most reliable method involves using specialized hardness testing files. These inexpensive tools can approximate the spike’s hardness level, helping you determine suitability for specific projects. For precise measurements, professional hardness testers like Rockwell machines are available but tend to be costly.
Working with Railroad Spikes: Preparation and Techniques
The Annealing Process
To facilitate cutting or forging, it’s often necessary to soften the spike through annealing. This involves heating the metal until it loses its magnetic properties, generally around 1500°F. Then, the spike must be cooled slowly in a controlled manner—preferably in a furnace or by wrapping it in insulating material—to prevent stress and cracking. Allowing the spike to cool gradually over several hours ensures optimal softness for machining or forging tasks.
Cutting and Machining
Once properly annealed, railroad spikes become much easier to work with. For cutting, using a band saw with a high-quality bimetal blade set at slow speeds yields clean results. Torch cutting is possible but generates a heat-affected zone (HAZ) that can compromise the spike’s integrity, especially if subsequent heat treatment is planned. Abrasive cutoff wheels are effective but require intermittent cooling to prevent overheating. Grinding tools are excellent for shaping and finishing the spikes.
Forging Tips
Railroad spikes lend themselves well to forging due to their size and material properties. Always ensure the spike is heated to a glowing temperature—around 1200°F to 1500°F—before hammering to avoid cracking. Cold forging is risky and can lead to fractures, so keep the spike hot during shaping. Proper heating and controlled forging techniques allow you to create a variety of tools and decorative items from these versatile pieces.
Creative Projects and Practical Uses for Railroad Spikes
While making knives from spikes is often popular on platforms like YouTube, it’s generally not recommended unless you’re aiming for ornamental pieces. The carbon content in typical spikes is insufficient for creating durable, high-quality cutting edges. However, they make excellent practice material for learning forging techniques. You can craft unique blacksmithing tools, such as:
- Letter openers and decorative items that don’t require a hard edge
- Wedges for axe and chisel assembly
- Ironwork accents like wall hooks, curtain tiebacks, or ornamental pieces
- Curved hammering blocks by embedding spikes into stumps for shaping metal
In blacksmithing projects, railroad spikes excel for creating functional and decorative components, especially when forging or welding. Just remember to keep them hot enough to prevent cracking and handle them with care to avoid damaging your tools or injury.