Box Jaw Tongs & the Cow Poop Theory of Blacksmithing
by Mark Aspery of Springville, CA
Stock: For this example 8 inches of 3/4 inch square A36 Hot rolled bar is used.
Rationale and Method
Box jaw tongs offer a number of advantages over open jaw tongs under most circumstances. Primarily the smith can take a relaxed grip on the tongs when forging without fear of losing the piece. The piece will not shift during the forging process when secured by the box. Making a pair of tongs was a milestone for a lot of blacksmiths. In times gone past a Journeyman Smith meant just that, a smith that went upon a journey to learn more skills before taking a masters test. When the smith appeared at the door of a prospective employer, he/she would be required to demonstrate their skills. A yard stick for this was to make a pair of tongs.
There are a number of skills used in making a pair of tongs. An understanding of the Cow Poop theory of Blacksmithing is a must.
The Cow Poop Theory of Blacksmithing
Imagine a freshly placed patty of cow poop at your feet. If, per chance, you were to jump into this with both feet, where would the poop go? Out! 360 degrees out. If we call the face of the anvil the field and the hot metal the cow poop, your hammer becoming your feet; striking a blow on the hot metal with your hammer will yield the same effects as jumping in with both feet. The metal will spread in 360 degrees. If you were aiming to draw a taper on this piece of metal, then the metal that did not move in the direction of the taper will have to be hit again in order to force it to cooperate.
Let us go back to the cow poop. Suppose that we now hit the cow poop with a Cricket (baseball) bat. Where would it go now? We may get a little on our gloves, but most would move perpendicular to the bat. We have directional control of the metal.
We can apply this to our forging in a number of ways. a.) Forge the piece over the bick or horn (a built in baseball bat), and b.) we can use the peen of our hammer (a smaller baseball bat), or c.) we can draw out with a fuller, or any combination of the above. In this way we are limiting the amount of metal that we have to move twice. We do more with less effort.
When you drive a piece of metal into the corner of an anvil (as in Fig. A) it yields the same result as driving a fuller into the metal. The fuller is shown for clarity. You will be using this technique in the first step in making these tongs. The jaw of the tongs will be only as wide as the parent stock, 3/4 inch, thus any gain in the width will have to be forged back into the stock. In using the corner of the anvil in this manner, we employ the baseball bat side of the “Cow Poop” theory and keep any growth in width to a minimum.
In Fig. B the piece is held flat on the anvil and a half faced blow is delivered. This results in the metal supported on the anvil being spread 360 degrees and the metal that is unsupported being driven down the side of the anvil. The result is termed a “set transition,” as if it were put there by a set hammer. You will use this, the “both feet” use of the Cow Poop Theory when you set down the boss or hinge plate.
There are a number of ways to make a pair of box jaw tongs. Some have the box extending all the way down the jaw. Others have half the box on each jaw. In this example, the box is about 3/4 inch long. In having a sufficient gap behind the box we can pass stock in from the side, as shown in example B. This is useful when we want to hold a bar for upsetting purposes etc.
In the following example it is assumed that the smith does not have an abundance of tools. There are other ways to achieve the same end results, but they are more tool intensive.
Hammer control is an issue during this project, and the smith is advised to make sure that the hammer being used is well dressed, with no sharp edges. That will aid in delivering blended, overlapping blows and improve the overall finish of the piece. The measurements given are approximate.
1 – Working on the near side of the anvil, place a chalk mark on the anvil at about the 1 1/ 4 inch mark. Place the end of the bar against this mark, lower your tong hand and match the angle of the stock as you deliver the hammer blows.
2 – Turn the bar over 180 degrees and work on the offside of the anvil, place about 3/4 inch over the edge. Keep the stock flat as you deliver your blows. Take care to avoid hitting the shoulder that you formed in step 1.
Go back to the nearside of the anvil and work out the resultant kinks formed by step 2. At this stage do not adjust any gain in width as shown by the arrow in step 2C, You will reduce this dimension in step 3.
3 – No matter what you do to the jaws of a pair of tongs, go back to your initial starting place of step 1-C and if you hold your tongs in the left hand, turn the top of the stock 90 degrees to the left. If you hold the tongs in your right hand, turn to the right. Move out to the offside edge of the anvil and while holding the stock flat on the anvil, orient the piece by sliding it to the left to approximately 45 degrees with the edge of the anvil.
The stock will tend to creep a little over the rounded edge of the anvil, so start a little further back (about 1/8 inch) than you would like. The direction of the creep is shown in step 3A by the arrows. Photos in step 6 shows the result of the creep in the slope of the transition.
Deliver a mix of half faced and moving further back onto the anvil, full faced blows. Stop when the stock is an even 1/8 inch thick.
4 – From step 3, turn the stock 90 degrees to the left (or right for the left handed smith). Move the bar out about 7/8 inch (Photo step 4 A), lift your tong hand and deliver your hammer blows, matching the angle of the stock. This will form the back edge of the boss or hinge plate.
5 – To dress the boss you will need to work from the front of the boss holding your hammer handle in a vertical plane. Move this front face onto the anvil and dress the rear of the boss (photo Step 5 B). Lower your tong hand and dress the bottom of the boss and then finally dress the sides of the boss. The boss should measure 1 inch between the flat sides and be 3/8 inch thick. I would repeat the cycle a couple of times rather than do it all in one cycle!
6 – You can choose to punch the rivet hole either now or later. There are pros and cons to each. Punch from the outside, with the shoulder over the edge of the anvil and finish by back punching over the pritchel hole. The punched hole should accept a 5/16 inch rivet.
7 – You have finished with the set up for the box jaw side of this pair of tongs. You must now turn the bar around and make a flat jaw side. This is identical to the previous side except that you move the chalk mark on the anvil back towards the edge by about 1 inch or so. Omit the steps that isolate the material for the box.
8 – After the second jaw is made, the bar must be cut in two, the ends drawn out and scarfed for a lap weld. I only work from the A & B sides when I draw out the reins in order to protect the stock transitions.
The placement of the scarf is important. As you look at the jaws, there’s only one flat side. I have found that this needs to be on the anvil at the time of welding in order to make the weld go a little easier.
Keep the flat side uppermost as you make the scarf, this will ensure that the scarf has the correct orientation.
9 – 20 inches of 1/2-inch diameter is used for the reins, this gives you a little extra in case of mistakes. A jaw of the tongs is welded to each end. If you are upsetting the ends of the 1/2 inch on the anvil, remember to upset both ends before making a scarf, otherwise you will have to upset the other end in the vice.
The cross pein, fuller, or a piece of round bar stock, is driven into the material at the end of the jaw to spread it sideways. The order is important.
First divide the material down the middle. Next, making sure that you don’t create a cold shut, work one side out. Come back and do the other side.
10 – The next step is to form the box.
After spreading the mass to create the sides for the box, you will need to fold them up to make the sides of the jaw. There are a number of ways to do this. Having made a few pair of tongs for my school, I have found the following way to be the least troublesome, producing a clean result.
The vice insert (Photo step 10 A) shows a piece of one inch half round welded to the back of a piece of angle iron. The angle iron is held in the vice by means of the bailing wire. This allows it to pivot freely from both sides and allows you to move the insert along the jaw. On the front of the angle iron is welded a piece of 1/2 x 3/4 stock, with the 3/4” side on the angle iron. This will act as a spacer as you form the box. Remove any sharp corners.
You will find this tool very useful for gripping non parallel stock. I have a number of different spacers and lengths of insert etc. depending upon what it is that I am working on.
The angle iron will pivot around the one inch half round as it attempts to grip the non-parallel stock.
Take a heat on the tong jaw and clamp in the vice with the edge of the jaw and the edge of the spacer in line. Taking a small set hammer (this could be a piece of square stock the appropriate size, with the edges rounded). Strike the set hammer and lifting up as you go, bend the side of the box over. Be careful not to shear the tab as you start the bend.
Take another heat on the jaws and repeat for the other side.
11 – Mark center and drill the rivet hole if you haven’t already punched the hole. The wooden block acts as a spacer so that the jaws can lay flat under the drill. I usually use a 5/16 or 3/8-inch rivet to hold the tongs.
Fit the tongs together and rivet. The tongs can be adjusted by placing the stock that you want them to hold, in this case 3/4 inch wide by 1/2 inch thick, and hammering the jaws together.
I adjust the reins in the vice using a pair of ‘Dog wrenches.’ The photo is of a pair of scrolling tongs, showing how the stock they are sized for is inserted between the jaws to protect the jaw setting while the jaws are clamped in the vice.
Mark has authored a number of blacksmith articles and books.