My nephew built a pen. I have to share because his process was amazing, and yet another example of creative, persistent problem-solving. The short version is he took a brass rod that my late father-in-law used in his garage for various tamping and pounding tasks over the years. Brad bored it out, ordered some things online to help create a bolt-action model he liked. After a lot of steps and hard work there sat a pen.
He made a frickin’ pen.
Yes, I’m impressed. There were mistakes along the way so he had to change course many times, but I loved his persistence. If you want the longer more technical version see below. I’ll let him tell the story, because… well, I don’t understand most of it.
I might add here that Brad the nephew is a former third grader of mine. That’s another story… Sometimes a teacher’s job is to step aside and let the student shine, so I’ll do that now. Again, mostly because this is way beyond my capabilities. My “pen” would likely be a piece of charcoal from the fire pit scrawled onto an uneven rocky wall.
His final product is on the left. The one he modeled it after is on the right.
Here is the main body of the pen, its two brass end caps and the aluminum clip. The body required seven operations to make. In order they are cutting to length with a hack saw, drilling the U (part of the A-Z series of American standard drill sizes) through hole in the 1/2” bar stock, tapping the writing end with a 7/16-UNC14 tap, drilling the reverse end to 25/64” to slightly widen it, tapping the wider hole with a 7/16-UNF 20 tap, pre drilling the slot with a 1/8” drill, and finally cutting the slot with a 1/8” tungsten carbide end mill. After that it’s all sanding and polishing to whatever finish you are going for. (I went with a polished finish using brasso as the final buffing compound)
Notes: UNC and UNF stand for unified national coarse or fine respectively. The threads are similar in diameter but have different threads per inch making them incompatible. I did this so that you can’t assemble the pen backwards. The tip only fits on the front.
The slot had to be pre drilled because even though the end mill is center cutting and could drill strait into the brass, it doesn’t like to. End mills work better when cutting on their sides not their front.
The rear cap is pretty simple and only took four steps. Cut to length as before, reducing the diameter of the threaded section with a carbide bit, tapping the threads with a 7/16-UNF 20 die to match the body, and cutting away the bad threads with the carbide bit.
Notes: Taps and dies both work by incrementally cutting threads. This means they are tapered so that every time you go around, they cut the threads a little bit deeper. When trying to put outside threads on a rod with a wider head on one end like the end cap (and the pen tip for that matter) the die can only cut so far before it runs into the larger diameter. At this point, the threads near the back of the die are well cut but those right at the front are barely started. These shallow threads cannot mate with the deeply cut threads at the rim of the body of the pen. If you try to screw on the back cap as is, the threads will bind up when the cap is a quarter inch or so away from being fully on. To fix this problem, you have to cut away the bad threads on the cap or drill out some of the threads on the body. I chose to remove those on the cap because it makes for a nicer looking setup. The washer then made up for the reduced diameter so the clip still fit.
The clip is also a simple part and one that has more to do with style and personal taste than anything else. You could make this part with a wide range of hand or powered tools but I chose to use my end mill again because it removes material wonderfully fast. To make this part, I drilled the hole for the end cap, drew out the spoon shape I wanted in pen and sculpted out the shape with the end mill. Then it was off to the usual battery of files and sanding to get the finish right.
Note: To make sure that the outer edge of the ring lined up with the body of the pen and end cap, I waited until the three pieces were assembled to file the clip flush.
After I got the finish the way I wanted, I put my personal mark on the clip by brushing a circle on the front with the tip of the end mill.
The tip of the pen is the most complicated piece of the entire pen. This is because the geometry is so complex for its size. The entire thing took nine steps. First, cut to length, then turn one end to a diameter so it can be tapped, then pre cut the new surface to remove the area where bad threads will for as before, flip the part around and cut the angled front to 18.5 degrees (with respect to the parts turning axis) with the same carbide bit as before, refine the surface and ensure flatness with a file, mark the center of the front with a drill bit and drill the small diameter for the tip of the ink cartridge, flip around and drill the larger diameter to allow for the thicker part of the ink cartridge and the spring, finally, tap the threads . All in all this took me three separate attempts and almost a week’s worth of work.
The bold isn’t in this picture but I think you have one with it too. This was also a pretty simple piece. All I had to do was grind the stem to the right diameter, grind a ruff ball shape, and refine the ball with a file. Simple and quick.
The inner rod is the final piece and I haven’t made it yet. I had to buy a shank of M2 high speed tool steel because it was the only material in the right diameter. Consequently, it is harder than hell and nicer steel than my drill bits. I have to wait for two tungsten carbide twist drills come in the mail to finish that part.
That covers all the pieces of the pen!
This picture shows my digital calipers. These are essential for any metalwork that requires precise geometry. Metal is a lot less forgiving than wood so a normal ruler is usually not good enough. Most any caliper will be good enough for this project but nicer is always better. This isn’t a top of the line tool but it’s a good one.
This is my set of taps and dies for cutting threads. It’s a relatively cheap ($80) set of Taiwanese tools but so is the way of buying taps. Get a cheap set to start off with and replace the ones that break with good USA tools.
Here are the three attempts I made at the pen tip. Note that this does not show a progression of steps. The first piece was drilled off center, turned poorly and tapped with the wrong threads. The second was also poorly drilled and used flawed methodology to cut the angle. The third I got just right and it ended up exactly as I would have hoped.
This is a set of tungsten carbide bits for turning parts. (Turning is when you spin the part and use a tool to reduce its diameter. This is opposed to facing in which you turn a part and use a tool to reduce its length.) These bits are fancier than most, maybe even gimmicky, but I thought I would give them a try having only ever used standard carbide bits. They seem to work fine and the rotating /replaceable cutting surfaces are a plus.
This is me with the old drill press. Drill presses are pretty crude for this kind of work. To do this project properly you would need a lathe, mill and vertical turntable to cut the slot and shape the parts. However, for the poor home gamer that’s just trying to get by, a drill press can hack its way through the process. Here’s why drill presses are not precision machining tools:
Drill presses are great if you use them for what they are designed for- drilling vertical holes. They are not so good at cutting with end mills or turning parts like a lathe because of how they are set up. First, drill presses generally use chucks. These are three (sometimes four) jawed contraptions that grip the tool and or the part. Chucks are versatile and quick to use but lack precision in centering. Good cutting tools are usually held with a collet. A collet is a tool with a hole cut through it the exact size of the shaft of the bit. When the collet is put in the collet chuck, it tightens down on the bit and holds it very tight and very strait. Yes lathes use chucks too but not the dinky drill kind. Think four inches in diameter and two inches thick. Much more carful machining and centering with those.
Second, drill presses are not designed to take axial loads. They are great in the up and down axis but are terrible in the side to side. This can cause chatter when cutting laterally as the whole quill rattles around.
For all this, I still use my drill press for everything. The point is to get to know the tool, its limitations and your own. Don’t expect a $200 misused drill press to crank out parts like a $150,000 Haas CNC. Take pride in the apprentice marks and irregularities!
Above is the bench grinder. This little ripper can tear off material like no other tool in the shop. It sucks at most things because of its limited uses but when a job suits its style, it can cut hours off an operation. Avoid ever using aluminum on it. That sticky mettle will clog up your grinding wheels.
These are my two tungsten carbide end mills. I use them for cutting just about everything. Carbide is so hard that it is pretty hard to mess it up. It will chip if you impact it too hard but other than that you can cut everything from plastic to steel without dulling the bits much. I got a couple of nice USA end mills off the old amazon and they have never done me wrong. Even without a mill (the tool they are meant for).
Brad’s journey building a pen. The final product is below.