The Snarling Iron – A Forgotten Tool Brought Back to Life Thanks to the Pro Monumenta Project
Author: Ladislav Gulyás | ⏱️ 3–4 minutes, photo: Ateliér kovu Ladislav Gulyás
"The biggest mistake would be to keep your knowledge to yourself," someone I respect most—my wife—told me not long ago. I have to admit she was 100 percent right. Artistic blacksmithing, craftsmanship, and our traditions can only be preserved in this consumerist world if we don't keep our knowledge to ourselves, but pass it on to as many people as possible.
Since July 2026, I have been collaborating with the Monuments Board of the Slovak Republic as part of the Pro Monumenta project. This project focuses on the preventive maintenance of historic buildings. Whenever possible, we work together to repair what we can rather than immediately resorting to replacement. Within the scope of our expertise, we also repair downspouts, elbows, and gutters.
And that's exactly what gave me the idea to revive a tool that almost no one uses anymore—and that many people may not even recognize.
While studying at the Secondary School of Applied Arts (SŠUP) in Hodruša-Hámre, I came across a book titled Pasířství by Karel Goňa. For metalworkers, it is a very informative and valuable resource. It was in this very publication, in the chapter on metal forging, that I first read about a tool called a snarling iron.
This tool is primarily used for hammering and shaping vessels from the inside—for example, when making a vase. It consists of an upper needle, which marks the spot where the tool will strike, and the body of the tool itself. To use it, tap the end of the arm (point 1); thanks to resonance and spring vibration, the tool will begin to drive the material out on the other side (point 2). It can be secured in a wooden block, in the square hole of an anvil, or in a blacksmith's vise.
Manufacturing the Tool
I used 25 mm diameter steel round bar, grade S235JR (STN: 11 375), as the starting material. I first forged the circular cross-section into an oval shape along its entire length. I then began forging the final shape at both ends. Even in the design phase, I outlined two important points:
- The end that will be struck
- The end to which the interchangeable anvils will be attached
Since I knew that the material in question wouldn't withstand long-term striking stress, I welded a piece of an old hammer to one end (point 1). I have plenty of hammers like this; they regularly set them aside for me at the local scrap yard. I drilled through the other end, creating a 12 mm diameter hole (point 2).
I made the lower stand from a 27 mm diameter C45 / C45E (STN 12 050) steel round bar. I forged the top into an oval shape, while at the bottom I forged a pin that allows the tool to be easily clamped into a vise without moving or rotating during use.
I marked the center, placed both parts together, and welded them. Throughout the process, I made sure that the weld did not cause the material to twist in any direction.
Making the Anvil
For the anvil tip, I once again used 25 mm diameter round steel bar designated S235JR (STN: 11 375). Since I knew in advance that the tool would be used to repair copper downspouts and elbows, I did not use tool steel—that would have been completely unnecessary. I shaped it to the desired form on a bench grinder and welded a 12 mm diameter screw with a strength grade of 8.8 to the bottom.
Manufacturing the Indicator Needle
An integral part of the snarling iron is the so-called needle. It is a guide that allows you to see exactly where the tool will strike from the inside. For its manufacture, I used 20×3 mm steel strip of grade S235JR (STN 11 375). This is a hot-rolled material that offers guaranteed weldability, good formability (even cold), and is easy to machine—both drill and grind.
I welded two strips to the body itself, drilled through them, and used 6 mm solid rivets to connect the needle to the tool frame.
I believe this short post will help breathe new life into this tool. We at Pro Monumenta will certainly put it to good use. In the video below, you can see exactly how the snarling iron works when repairing a copper downspout.