Before Christmas I had a friend ask me if I could build a reproduction of a Hudson Bay camp knife for him and before I knew what I was getting myself into I agreed. I don't make that many knives and never anything this big, so I am somewhat of an amateur at this business. Some of my procedures probably appear rather silly to those more experienced here, but hopefully you will enjoy watching the process as it unfolds. If you have any suggestions to improve the process I would greatly appreciate hearing them.
I started the process by researching this style knife on-line and using various photographs and other written documentation I was able to arrive at what I feel is a fairly close approximation of this style knife. Big and heavy is one way of describing these Sheffield made knives of the mid 1800's, perhaps scary is another good adjective to use. The sample I used as a basis for this project was by Jukes & Coulson and measures about 13.5 inches long a hair over 2 inches tall at its widest point, and close to 1/4 inch thick along the spine. The handle tang is tapered and the handles are buffalo horn bound in brass plates and washers. Using what I had I ended up drawing the project in CAD.
The above drawing is mostly correct I feel, but the handle slabs I later found out do not taper as I have in the drawing, but remain constant in thickness. I have not had a chance to make these changes, but I will in the finished knife. The first step was to profile out the blank from a chunk of 1/4" thick 5160 steel I had in the shop. I used a vertical bandsaw to do this but unfortunately I was not able to capture any pictures of the process. Maybe when Google Glass is available hands free photography will be easier.
I left an extension on the end of the knife blank that I am going to used to mount the blade to a tooling plate on the angle table of my milling machine. On a knife this size there is a lot of metal that needs to be removed and it is more economical for me to mill it off than it would be to grind it, I have the capability of sharpening my milling cutters, but I haven't figured out how to do the same with my sanding belts.
I cut out a clear plastic pattern to use to check the profile with as I cleaned up the bandsawed blank on the grinder.
After doing this I decided to make another pattern that had the locations of the pin holes marked out as well as the location of the ricasso edge.
With the holes and ricasso layed out I proceeded to center punch the marks using an optical center punch. (I later moved the ricasso forward a bit since it didn't look quite right to me as I had it marked.
The handle tang is going to be tapered and I figured it would be easier to drill the holes into it while the surface is still flat so the holes were spotted drilled first with a center drill and than with a 1/8 inch bit.
Following this all the holes were given a slight chamfer using a center drill in the cordless drill. This was primarily done to debur and remove any chance that the blank would not sit flat on the tooling plate.
Next I marked a line along the center of the cutting edge and than created two lines parallel to it at .015". This will leave an approximately .030" wide edge that I will mill to. Later it will be ground down to about .010-.015 prior to heat treatment. Here I used a surface plate and height gauge to do the work, but a caliper would work just as well.
After making sure that the blank was deburred on all sides I mounted it to my tooling plate on the milling angle table. The angle table will allow me to precisely mill in the tapered sides of the knife and keep both symmetrical. Some would probably consider it cheating, but as I said earlier it is actually more cost effective for me to do it this way and since I have the equipment why not. The mill is nice, but even when finished it still leaves a great deal of material that must be removed by other means. A manual mill does not handle the compound curves that exist in most knives easily and this one is no exception to the rule.
My tooling plate was a chunk of thick aluminum that I bolted to the table. I originally planned on screwing it to the plate, but opted instead to just use large c-clamps to hold it. I used two clamps to hold the blade to the plate and two additional clamps to provide stops to prevent the blade from shifting under the stresses created by the milling operation. I was careful to align the edge of the ricasso with the movement of the table. The angle of the table was set by trial and error. I touched a tooth of the end mill off of the front edge of the blade and than moved the table so the bit was on the flat near the spine and recorded the height at this point. By doing some quick calculations I was able to arrive at a suitable angle that would allow the milled plane to end at the correct position along the spine. Here is the blade mounted on the plate initially. I used a edge finder in the drill chuck on the mill to trace the line of the ricasso to ensure the blade was mounted square.
Once everything was setup I installed a 1/2 inch end mill in the collet and proceeded to mill the blade flat.
Cuts taken were shallow, about .010-.020 because the setup was far from being ridgid enough for comfort. I really did not want to lose the blank after the time that I had already spent on it. After awhile the cuts neared the guideline that I had previously scribed.
Since the blade curves it was not possible to cut the entire face evenly without repositioning the blade. This was done and milling proceeded.
Now everything was even along the guidelines that I had marked out.
I took the blade off the tooling plate, de-burred with a file, and than recorded the mark along the spine where the milled taper ended. I used a caliper to take this measurement and than transferred it to the opposite side of the blank. This way I had a visual to track so I knew when I had reached the right milling depth. This provided me guidelines both on the front and the back to reference too which helps keep everything symmetrical.
Once this was accomplished the blank was remounted on the tooling plate, aligned with the edge of the ricasso, and milling continued the same as on the other side.
I found the edge of the ricasso on both sides was not quite right, but a bit of tweaking fixed the problem and any further refinements can be made when grinding the blade down the road, or with a file.
The finished milled blank was symmetrical, but very rough and the taper was only going in one direction, not compound like the finished knife would be. Not having an extra hand to photograph me I was not able to record the next few steps which included bandsawing the blade tip to remove the waste material and than the rough grinding. The tip got wider at the point and this needed to be blended in with the rest of the blade. The grinding was accomplished using an 80 grit belt, the shape of the blade will be further refined in subsequent operations, but here are the shots as it currently is.
Lots of work is left to be done, but it is starting to look like a knife and a rather heavy duty one at that.My next task will be to grind the tapers into the tang and than stress relieve the blank which has had some serious metal removed from it. Hopefully I haven't bored you too much, thanks for looking. Until the next time.
Regards,
Alex Johnson
