For a geologist, chemist, or industrial worker, one of the banes of your existence is probably the venerable china marker. They are a wax-based colour pencil, with an outer casing of paper for rigidity that is supposed to be 'easy sharpening' or 'easy peel' along perforated lines. They're extremely useful, being able to mark on pretty much any surface with a semi-permanent mark that is easy to draw and highly visible.

The sharpening of a china marker is simple: pull the string down, and then peel off a layer of paper along the perforated line. This all too often ends poorly.

The paper these china markers are made from is usually pretty high grade stuff, but that doesn't help much if it gets wet, or sits too long, or gets dropped, or you peel too quickly, or too slowly, or at anything but the perfect angle. It doesn't take very long before you get frustrated with the whole business and end up with something that looks like a mess and doesn't support the lead properly, leading to the weak lead breaking and frustrating you even more.

There are plastic versions available on the market that ratchet like a mechanical pencil but they tend to be prohibitively expensive compared to the paper ones so companies tend to go for the cheaper, more available option. They also aren't necessarily available in colours needed for coding in your workplace.

Step 1: Supplies

The magic ingredient is Sugru. It is a self-drying rubber clay that can be molded into whatever shape you want, and stick to pretty much anything. It's quite durable when fully cured, great for modding.

You will also need a pen-style eraser. I used a Staedtler, but there are lots of others on the market, they all work on more-or-less the same principle.

Tools:
-Drill bit. I used a 3/16, as that was the closest match to the leads I have. If you can't get a perfect match you should err on the side of smaller, since the cured Sugru is spongy and will 'give' a little. (No need for a drill)

Step 2: Disassembly/Molding

You begin by disassembling your eraser. On the Staedtler version this is done by popping the end cap off and zipping out the little sled that holds the eraser. The end cap pops back on easily when you're done.

Open up a packet of Sugru and start molding it in your hands to get it nice and pliable. Once it is warmed up mold it into a slightly pointed shape and push it into the sled of the eraser, getting it as densely packed as you can. Peel the excess off so that it's flush and smooth with the edge of the sled.

Next is the "business end" of the marker. Push the eraser up into the tube so that it rests about 1cm (1/2") from the end. This will be used as a mold so that you can get the Sugru tight to the outside of the casing. Roll the leftover Sugru into a point again and push it into the hole, holding the eraser in place. Again you will want to make it as dense as you can. Use your fingers to round and smooth the outer part of the Sugru. Remove the eraser so that it doesn't set into the Sugru. Discard any excess Sugru or use it to make more markers.

Once everything is to your liking, allow the Sugru to set for 24 hours.

Step 3: Drilling

Once your Sugru is set the next step is to drill a couple of holes. This can be the tricky part.
The Sugru is much softer than wood so using a drill would be overkill. Set the marker casing on a table or flat surface and align the drill bit as straight as you can with the length of the casing and the centre of the plug of Sugru. The hole will only be a centimetre long so it doesn't have to be perfectly straight, but the straighter it is the better it will work.

Twist the drill bit with your fingers gently to drill a hole until it pokes through and give a few more twists to ream the edges nice and smooth. Do the same with the sled.

Step 4: Reassembly

Once your holes are drilled it is time to reassemble the marker. Put the sled in the casing, put the cap back on, and you're done.

Now comes the fun part: pull the string along the whole length of your old paper china markers and peel the paper off in one big sheet. Be careful to keep the lead as straight as possible as they are quite delicate. You will probably need to cut the lead in half to fit in the new marker. Simply insert the lead as you would a new eraser and use your handy new markers. As the lead gets worn down advance it with a satisfying click.

Be sure to make one for every colour you use. It's up to you whether to bask in the envy of your coworkers, or to be the hero your workplace needs and make them for everybody.