The Amateur Crafter: Project 3.0 - Chillin' & Drillin'

One of the goals about this project, and the purpose of equipping the shop, was to learn about the processes into making a knife. By that I mean a custom knife. Learning about these processes allows a deeper understanding towards manufacturing the product and gives insight into areas that need improvement, in particular processes that produces 'hit-and-miss' results. The process where I am (or rather was) at in my knives is one of those steps that didn't produce the expected result. I'll explain.

To lighten the weight of my knives I intended to drill out some holes along the handle. This is a common practice by all professional knifemakers. I knew that removing material from the blade when I grind it would make the knife heavier in the handle. I want these knives to be balanced more at the choil, just behind the back of the blade. 

To do this I first laid out the template and put four 3/8 inch holes along the handle area. While I was at it, I went ahead and drilled out the holes for the 1/8 inch handle pins. Since the template was thin material (1084 steel I think) this was pretty easy to do. Also, I did this at the shop at work on a large vertical knee mill. This provides a considerable amount of rigidity. However, my knives are 5/32 inch thick and made of 1095 steel. And I'm trying to do this process almost entirely in my shop. This means I'll drill out the 3/8 holes on my little bench-top drill press. First I marked the location of each hole.

Next I center punched each location with my automatic punch. Then I simply lined up each punch mark with the tip of my drill on my drill press. 

This also gave me an opportunity to test out my drill press clamps (sometimes called "toe clamps").

Despite the blade having a secure, rigid mount the holes didn't come out good at all. Compared to a large milling machine, my Central Machinery drill press just doesn't have the same structural stability - which means that the holes turned out to be more of a Reuleaux Triangle in shape rather than a hole. Note this diagram retrieved from Tanya Khovanova’s Math Blog. 

From the image, the right shape shows a "rounded" triangle. This is the type of hole that was produced on my drill press albeit more exaggerated in the image. Note the photo.

It may not be as visible but the holes are not round much at all, plus the walls of the holes are very rough. This might seem trivial especially since the holes are along the handle which will be covered by scales anyway. And it's true, along the handle those 3/8 holes won't matter much at all. However, the holes for the brass handle pins might not work with the brass rod. Also, as I am wanting to work towards the creation of my own custom folder knives, I will need to resolve this problem if I want the pieces to fit together properly on future folders. This means that I need accuracy through rigidity. 

Since my drill press can't really provide me with much, I needed to improvise. This is something I try to teach my students as much as possible - learn to improvise. To complete a job, one may not always have access to high end stout machines and high quality tools, yet the job must still get done. Being able to improvise and work around the limitations of a shop is one of the best skills any technician could develop. I decided to try additional tools. 

Enter the center drill, sometimes called a combination drill/countersink. Note the following image from Harvey Tools.

Note also the type of hole a tool like that will leave. The cross section shows a beveled hole (countersink) leading into a small cylindrical hole. Doing this first before drilling out the 3/8 holes will provide a better "center" for the drill to start on. Additionally, I decided to purchase a "screw machine" drill rather than continue to use my jobber length drill. A screw machine drill is much shorter and less likely to "walk" during use. Also center drilling first then immediately drilling out the hole afterwards, without moving the work piece, will improve my accuracy.

Because I didn't have these tools available, I had to purchase them online. 

This is a #2 x 4 inch center drill.

Here one can see the screw machine drill next to the jobber length drill. The shorter length gives greater rigidity.

Once I got the tools in I started back on my process. Last time I drilled these I had them marked with just a permanent marker. That didn't hold up to normal wear so I decided on something stronger.

The steel dye (called Dykem) can provide a durable coating on the work pieces that'll withstand oil, coolant, and water. This also allows me to scribe the location of the holes.

This allowed me to simply line up my center drill in the middle of each scribed circle. No center punch needed.

I also added an extra drilling operation before I drilled the final size. This is known as pilot drilling. Using a smaller sized drill than 3/8 I drilled out the hole, which puts let burden on the larger drill bit due to less material removal. On larger machines, this is not an issue. But my small drill press doesn't have the same horsepower as the larger machines so my larger drill bit has to work harder to remove material. Putting a smaller hole there first means that the drill doesn't have to work as hard now to produce a hole.

A good result. Note the "cushions" I used on the table clamps to protect the blade from scratches by the "toes" of each clamp.

The final result. The steel dye is still visible on 4 of the blades

The blades are now tip heavy and will probably balance back at the choil once the grind has been completed. Speaking of knife grinding, the following photo shows the angle iron stock I plan on using to make my grinding fixture for my knives. I've taken the time to file, sand, and scotch-brite each side to a good flat surface.

This is how I plan to mount the blade onto the fixture. I'll need a bit of planning to work it out. That'll come in the next article. 

Despite this particularly long delay happening, it was not only expected but needed. I had to figure out if my drill press would be capable of producing the result I needed it to. I do plan to purchase a larger bench top drill press, possibly even a floor model if necessary. But I wanted to wait until tax time to do it because that'll be a substantial purchase like the Grizzly. At least, if I purchase one with any structural integrity I'll have to pay much more than just the price of a cheap-ee Harbor Freight model.  Thankfully, the tooling worked out just fine. This method does add more to the time to produce it. Because I'm concerned with accuracy, I must center drill, then remove the combination drill/countersink, then mount the pilot drill, drill out the pilot hole, then remove the pilot drill, then mount the 3/8 inch screw machine drill, drill out the 3/8 hole, then finally unclamp the work piece to move to the next hole and repeat the steps. I cannot center drill each hole on every work piece while the tool is mounted and then remove it for the next tool, not if I wish to maintain any degree of accuracy. To get an idea of this, imagine center drilling, then drilling, then drilling again 4 holes for 5 separate knives and each time you drill or center drill once, you must stop what you are doing and then switch tools for the next operation. It really adds up to a lot of time. Fortunately, the result is exactly what I wanted. After grinding all that's left to do is heat treat and put the edge to each blade and start working on the final product which will be mounting some material on each side of the handle for the scales. I can now see a final result in sight!

Up next, creating the grinding fixture!