Blacksmithing Processes -- Part I
by Fred Holder
[Reprinted from January 1995 issue of Blacksmith's Gazette. We have chosen to reprint this series because of a number of new subscribers who are beginning blacksmiths and are looking for basic information. I hope the longer term subscribers will put up with this reprinting, we feel it is necessary.]
All work that a blacksmith does consists of a number of basic processes, which when taken together allow him or her to produce very complex forgings. In this article, we begin to explore these processes. Once each of them are mastered, the beginning smith is ready to begin applying them in more complex situations. The processes that I am talking about are:
I consider these to be the basis of virtually all blacksmithing tasks. Once a smith has mastered these, only the imagination is the limit of what he or she can do. Always, the smith should strive for perfection, although it will generally elude most of us at all times. But, by striving for perfection, one willseek to accomplish the best that they can do at any time in the development of their skills. Remember, each botched job can be looked upon as a learning experience. If one approaches the task in this manner, it makes those botched jobs a little easier to take.
The sequence of events in most of the operations is to bring the steel to a red/orange heat, place in upon the anvil, and strike it with the hammer. It is recommended that the student practice each of these operations over and over until they become second nature. A good way, to do this for the rounding and squaring operations and still go ahead and make projects, is to always make things requiring square rod from round rod and those requiring round rod from square rod. But do not move too far forward in your learning until you have first become quite proficient with each of the basic operations we are discussing here.
I thought that I might compare the various methods to accomplish these basic tasks that different authors had used. When I looked in most of the books, they said now square the stock, but generally squaring and rounding were dealt with in a project or not at all. I'm tackling these tasks in the order of importance as I see them. I'll probably get some flack from some of our readers at least about the order of importance, but remember right or wrong, I'm telling you the way that I do it and the way I see it. Also, we must always remember, there is no wrong way if it obtains the right end result, only different ways and sometimes those different ways are a whole lot easier! This latter thought is what Blacksmith's Gazette is all about, finding the easier way!
In squaring, the steel should be placed as flat as possible upon the anvil and as near to 90 degrees to the edge of the anvil as possible (this latter may not be necessary, but I've always found it to be easier). The hammer should come down with the face as close to parallel to the face of the anvil as possible. I have a fairly flat faced hammer that I like to use for this operation, but within reason most any hammer will serve the purpose. Strike in the same place, somewhere near the center of the anvil face, with each blow. Move the steel rod back and forth under the hammer as a flat space is created.
Do not start your hammering on the end of the rod. Start back a few inches and then work toward the end.
Do not hammer too long in any one place, but attempt to make the surface on which you are hammering as smooth as possible and the width of the flat surface approximately the same width along the full length of the area being squared.
Do not hit the material too hard. Your goal is to flatten from two directions at 90 degrees to each other until you reach a point at which each the dimension is the same and the rounded corners have become as pointed as much as you desire. Hit it too hard and you create a deeper area that you want that is hard to correct.
Obviously, you can only work on the area that is hot. In the average coal forge, this will be somewhere between three and six inches. You can extend the length of the heated area by moving the steel back and forth in the fire until a longer section is brought up to proper heat.
Unless you work very fast, it will be a good idea to return the piece to the fire for another heat before rotating the work an amount as close to 90 degrees a possible. Repeat the above described process. You will now have a piece of round rod that has been hammered into an octagon shape with four of the flats still retaining the rounded form of the original round rod. At this point, you could now work on the rounded flats and hammer them as flat as possible to create an octagonal piece, but here we're working on creating a square, so let's move on. Figure 1 shows the sequence of shapes from round to square. As we continue the hammering on each of the flattened portions, the rounded sections become smaller and smaller. It is a good idea to hammer on one set of flats for the length of the heat, rotate the rod 90 degrees and hammer the next set of flats for the length of the heat. How many times you can do this between heats depends upon how fast you can work. The fewer heats you can take the better because with each heat you lose a little bit of your steel to scale.
Figure 1. The Sequence of Shapes from Round to Square.
Note:After each hammer session, before the steel is returned to the fire, it is a good idea to lay the steel along the length of the anvil face and straighten it as much as possible to eliminate any curve that has developed from the hamering. This helps to keep the rod straight and makes it a bit easier to handle.
Remember, you are squaring the steel. If you were to cut the rod in two, the cross section of the piece should have four sides that are equal in length and the corners should form a 90 degree angle. See Figure 2. If you're not achieving this, and you still have some stock available before your square rod is too small for your planned project, you can correct this by hammering on the high corner of the square to force the high side down closer to the low side. In this operation, it is very important that you regularly rotate the rod 90 degrees to correct the difference between high and low sides at the same time. Once you have a small portion of the rod squared, it gives you a guide to square the rest of it.
Figure 2. The Cross Sectional Shape of the Squared Rod should be square and not canted.
As you continue this process, the corners will become less round and more sharp. You may not wish to bring the corners to a complete sharp point like those found on cold rolled steel. You may find it better and more pleasing to leave them a bit rounded like the corners found on hot rolled steel bars. Obtaining a sharp square corner; however, may require the use of a flatter, unless you have a very flat faced hammer like I use for this operation. Actually, I doubt that the corner will ever be really sharp, the rounded portion will simply become smaller and smaller until it looks and feels sharp, but the very point will still be rounded unless you have forced it into a swage of some sort.
I consider the squaring operation to be very important,
partially because I've seen so many squared rods that weren't
really square. Learn to hammer your work into a square and
you'll discover the other hammering operations are easier to do.
There's nothing wrong with using a small square to check your
thickness of the width and breadth. Actually, if your section
measures the same both directions and also the same across the
points both directions you should be fairly square.
When one is using a power hammer, such as an air hammer, you can place a piece of cold steel of the right height to limit the travel of the hammer face to a particular height. Thus, making squaring a piece of stock to a particular size much easier. In hand hammering, one could make a die that would limit the travel of the hammer face to a particular height thus forcing the material into a square of a particular size. This would be easier done if a flatter were used to strike the metal and a hammer or sledge to strike the flatter.
Using these techniques in the beginning would simply be a crutch to avoid learning how to do the job right with the hand hammer. After you've perfected your skill and eye, then for production purposes you may wish to use a die or some sort of jig. In the meantime, practice! There is no other way to learn blacksmithing!
Rounding is somewhat the reverse of the squaring operation. (See Figure 3.) For this discussion, we'll assume that you started with a square piece, but that is not necessary. If your piece is not square, then use the previously described method to make it square before you start the rounding operation. It is a lot easier to make a rod round from a piece of square rod than to do so from something that is not square.
Figure 3. The Sequence of Shapes from Square to Round.
Heat the piece of square rod and place it on the anvil with one of the points down and the opposite point as nearly vertically above it as possible. (See Figure 4.) We are now taking the square rod and making it into an octagonal shaped piece. Its a good idea to make every effort to make the flattened area the same width along the length as possible. Now, rotate 90 degrees so that the other point is on the anvil face and its opposite point is vertically above it. Hammer this point into a flat, again making sure that it is the same width along the full length of the heated area.
Figure 4. The Manner to strike the stock when converting from square to round.
Refine our octagon until all flats are as equal in width as possible and the shape is square. Check with your square to make sure that you're not skewing the shape. Its a good idea to make your entire length of rod to a good octagon before going on to the next step.
Ok, you've made as good an octagon as you can, you now have eight points and eight flats all the same size, hopefully. Repeat this operation of taking a new point, placing it on the anvil face (making sure the opposite point is directly above the one on the anvil) and begin hammering a flat along this point. You will create eight more flats to give you a total of 16 flats.
Now, repeat the operation again and you'll get 16 more flats, much narrower than before. Make all flats the same width if possible. You're beginning to have a fairly round rod by now. So, continue this operation until the flats become so small you can't tell where they are and you'll be as close to round as you can get without using some sort of a die.
Note: Always straighten the rod between heats before you put it back in the fire. If you don't, pretty soon the rod is all skewed out of shape and it becomes quite difficult to work with.
A swage block is a useful tool to have when rounding stock. Once you've made as many flats as possible you can start working the rod in a half-round recess that is close to the size of your stock. The flat areas are then being hammered into a rounded area thus making the bottom part more and more round. You are, however, still striking the top part with a hammer with a fairly flat face. The blows must be lighter and lighter as your rod becomes more and more round. Again, you can only round the rod so much because you are still striking with a flat surface.
To obtain an even more round surface, you'll need a pair of top and bottom swages of the proper size to make the rod nearly round. Hammering the swages together as the rod is rotated and moved back and forth between the swages will create about as perfect a round as it is possible to produce with hammering alone. And, for that matter, it will be as round as you're likely to need for most construction projects. It may not be round enough for an axle, but that is asking a bit much from a hammer and anvil.
Next month we'll talk about the related topics of Pointing and Drawing steel.
This article was originally published in Blacksmith's Gazette. It has been edited to fit the format of our Blacksmith's Gazette Internet Site.
This page was last updated on September 28, 1996.