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What is a Planishing Hammer?

Dan Cavallari
Dan Cavallari

The process of shaping sheet metal involves several steps of shaping and bending the metal until the desired shape becomes apparent. After several instances of sinking or raising--two of the techniques used to shape sheet metal--the metal itself will hold the general shape of the desired finished product, but these processes cause several ridges and dents in the metal. Therefore, the metal must be planished using a planishing hammer; this process smoothes out the metal and gives the final product a solid shape and finish.

A planishing hammer is a flat or slightly curved hammer that is used in conjunction with a planishing stake. A planishing stake is a solid metal pole that must be affixed to the ground to provide stability. Its top end is formed into a ball or other smooth, curved surface. The metal product is placed on the planishing stake, and the planishing hammer is struck against the metal product to work out ridges and other imperfections. A series of soft blows work best, as hitting the product too hard will cause dimpling.

A planishing hammer can be used to help shape sheet metal.
A planishing hammer can be used to help shape sheet metal.

The planishing hammer was used most often in medieval times to fashion suits of armor for knights. Today, the process of using a planishing hammer and planishing stake is somewhat outdated, though it is still used. Today, most planishing hammers are motorized and/or pneumatic, which speeds up the process considerably. They can shape, form, smooth, or stretch sheet metal, aluminum, copper, brass, and other metals. Common applications for the planishing hammer today are fashioning airplane parts, car body parts, motorcycle gas tanks and fenders, and other custom settings in which metal shaping is necessary.

Planishing hammers were used in medieval times to make armor for knights.
Planishing hammers were used in medieval times to make armor for knights.

Another type of planishing hammer is operated by a foot pedal. This is a non-motorized, free-standing planishing hammer controlled by a foot pedal that allows the user to maintain the use of both hands to guide the metal through the hammering process, as compared to the medieval process which necessitated the person planishing to hold the metal with one hand and the planishing hammer with the other. Some modern planishing hammers can smooth out steel up to 18 gauge, and planishing hammers can be useful in smoothing out welds and panel crowning.

Small anvils are used in place of the planishing stake on modern planishing hammers. The anvils come in a variety of sizes, the most common of which are one inch (2.54 cm), two inch (5.08 cm), and three inch (7.62 cm). Planishing hammers today vary in price anywhere from $100 USD to $800-900 USD.

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Discussion Comments


I collect a lot of old tools and I specialize in different types of hammers. I have antique douglas hammers, chasing hammers, claw hammers and estwing hammers. Some of these you would not even recognize if you were only familiar with their modern incarnations.

One of my prizes is a planishing hammer that is over 450 years old. It is crudely made and bears almost not resemblance to today's hammers, but it is still clear what it is is. If you saw it you would probably figure out that it is a planishing hammer.

That is what I love about this kind of collecting. You can see they way that so much of what we use today is a descendant from something that they used in the past. The craftsmen of the middle sage our not so far removed from the craftsmen of today.


I have never worked with a planishing hammer but I can remember seeing a pneumatic planishing hammer on a show about motorcycles. It was one of those shows about making custom motorcycles and the bike they were working on had to have this really oddly shaped but perfect looking gas tank.

A big part of those shows is something going wrong and people finding a reason to scream at each other. On this particular episode there was a critical point when the planishing hammer dies. They are on a deadline but the bike can't be finished. I'm sure you know where the story is going. They magically finish the bike and the client rides away happy. I would have never have expected that a planishing hammer could be at the center of so much drama.


When I was in college I helped a friends work on an art project that involved some really detailed sheet metal sculptures. This was a small college that essentially had no metal working shop so we were improvising a lot and making do with what few tools we had. About half way through the project we were able to get a hold of a planishing hammer and it made the project run so much more smoothly.

A big part of the idea was to have this incredibly flat smooth and untouched surface. But as we began to work with the metal we realized how easy it was to leave your mark behind. Before to long we ended up with a mass of sheet metal that was covered in pock marks.

It took us almost as long to fix our mistakes as it did to make the piece in the first place but it turned out really well in the end. My friend put it in an art show and someone offered to buy it for a really amazing price. That was the start of a long career in art for my old college friend

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    • A planishing hammer can be used to help shape sheet metal.
      By: Kybele
      A planishing hammer can be used to help shape sheet metal.
    • Planishing hammers were used in medieval times to make armor for knights.
      By: Dusan Kostic
      Planishing hammers were used in medieval times to make armor for knights.