Directional vs. Uniform Force: How Hammer Faces Control Steel Movement
For a blacksmith, the hammer is more than just a tool—it’s an extension of the hand, a shaping instrument, and the heart of the craft. Yet not all forging hammers are the same. Rounding hammers, cross peens, and straight peens each serve specific purposes and dramatically influence how metal moves under the strike.
Understanding the difference between them helps you work faster, shape cleaner, and control your material like a pro. In this post, we’ll break down what each hammer does, where it shines, and how to choose the right one for each task in the forge.
What Is a Rounding Hammer?
A rounding hammer features two faces:
One flat face (like a standard hammer), and
One domed or slightly crowned face, which is what gives the tool its name.
Originally popularized by blacksmith Brian Brazeal, this hammer has become a modern favorite.
What the Rounding Face Does
The rounded face:
Moves material quickly
Reduces sharp impressions
Makes isolated, controlled strikes
Helps create smooth, organic curves
Because the domed face distributes force over a smaller area, it pushes metal more aggressively. It’s ideal for forging bevels, drawing out material, breaking edges, or correcting minor misalignments.
What the Flat Face Does
The flat face offers:
Clean planishing
Flattening surfaces
Refining shapes after heavier blows
Best Uses for a Rounding Hammer
General forging and everyday hammering
Drawing out stock efficiently
Forging blades, tools, or decorative work
Straightening and shaping with precision
Skill Level
Beginner to advanced.
Its versatility makes it one of the most commonly recommended hammers for new smiths.
What Is a Cross Peen Hammer?
A cross peen hammer has:
One flat face
One peen face that is a narrow ridge running perpendicular to the handle
The orientation of the peen determines how metal spreads.
What the Cross Peen Does
Because the peen contacts the metal first, it creates a focused blow that spreads metal sideways from the strike. This gives you:
Fast material movement in a controlled direction
Ability to isolate areas of steel
Great accuracy for tight or detailed work
Best Uses for a Cross Peen
Drawing out bar stock quickly
Starting tapers (especially square tapers)
Establishing shoulders and transitions
Texturing and decorative lines
Forging in tight spots where flat faces don’t reach
Skill Level
All levels, but especially useful for smiths interested in controlled shaping or traditional European techniques.
What Is a Straight Peen Hammer?
A straight peen hammer is almost identical to a cross peen—but the peen runs parallel to the handle instead of perpendicular.
Where the cross peen pushes steel sideways relative to the handle, the straight peen moves steel forward and backward.
What the Straight Peen Does
Moves material along the line of the handle
Helps widen or lengthen metal in a chosen direction
Allows you to access areas that cross peens cannot
Gives directional control that matches your hand movement
Best Uses for a Straight Peen
Drawing out long tapers
Spreading steel front-to-back
Working inside curves or along thin areas
Forging in lines or grooves parallel to the bar
Skill Level
Intermediate, mainly because its benefits become more noticeable once you have a feel for directional movement.
How to Choose the Right Hammer for the Job
Choose a rounding hammer when:
You want an excellent all-purpose hammer
You’re drawing material quickly
You want smooth, controlled shaping without deep marks
You planish surfaces often
Choose a cross peen when:
You want fast directional spreading
You’re forging decorative ironwork
You’re starting a taper or creating shoulders
You need accuracy in confined areas
Choose a straight peen when:
You need to elongate steel efficiently
You prefer forging parallel to your hammer stroke
You’re working on leaf work, scrolls, and organic shapes
Pro Tips for Hammer Selection
Hammer weight matters: 2–3 lbs works for most blacksmiths; heavier hammers move more material but cause more fatigue.
Match hammer style to your project: Decorative work often relies on peens; bladesmiths lean toward rounding hammers.
Good handle fit = better control: The hammer should feel like a natural extension of the hand.
Practice striking accuracy: Technique is more important than hammer type.
Use the anvil as much as the hammer: Anvil geometry and hammer geometry work together.
Final Thoughts
Each hammer—rounding, cross peen, or straight peen—offers unique advantages that suit different forging tasks. Many blacksmiths eventually use all three, but understanding how they move steel will help you choose the tool that best matches your style, workflow, and projects.
If you would like to discuss a potential project with us, please do not hesitate to contact us.
