For Wild Gears Super Geeks: Modifications
UPDATE: Since this post, Aaron Bleackley, the creator of Wild Gears, has bought his own laser cutter to produce the gears. It cuts more finely than the cutter at Ponoko, where he used to have the gears made, i.e. the jagged edges produced by the cutter’s movement on the X and Y axes should be much reduced. Shop Wild Gears at this link.
More from Jay Heyl, who has provided some great ideas for Wild Gears storage. Jay has noticed that the laser cutting of the gears leaves an edge that is not perfectly smooth; it’s very slightly jagged, like steps on the X and Y axes, or like a pixelated edge if you blow up a digital image. I took out my jeweller’s loupe to look at some gears and I can see these lines, and I can feel their texture with a fine tool. You can kind of see it inside the holes and on the sides of the teeth in this photo:
Not satisfied with this edge, Jay writes:
I have one other rather geeky “modification” I’ve done to many of my Wild Gears…. smoothing out the stair step edges left by the laser when the gears are cut. These can cause an irregular movement as the pen slides around the hole and result in the lines having jagged sections. The stair step on the gear teeth can make the gears not slide against each other as they should. This can make the larger gears stick when using the outer holes and can make the smaller gears jump around. The stair steps eventually wear down from use but it can take a very long time for them to become anywhere near smooth.
Enter the diamond coated burr bit set. This set was less than $10 from Amazon.
This sloped conical burr (right) is a perfect fit for the small pen holes. You can do it totally by hand, simply rolling the bit between your fingers while sticking it in the pen hole, but that will likely wear your hands out pretty fast. I put the bit in a cordless drill and set it to screwdriver mode to slow the bit speed. Run the bit into the hole all the way to the end of the diamond section. Just a quick in and out is sufficient. I do all the holes from one side of the gear and then turn it over and re-do them from the other side.
You do need to watch what you’re doing when using the drill. These bits are covered in diamonds, the hardest natural substance known to man, and acrylic is not remotely close to the hardest substance known to man. With a short span of inattention you can turn a nice round pen hole into something more like a pen slot. This bit isn’t bad because the conical shape helps it center itself in the hole and it’s almost the perfect diameter. Quick in, quick out, you’re good to go.
None of the bits in this set is a perfect fit for the larger pen holes. I use one of the barrel bits and slide the gear around the bit when it’s inserted in the pen hole. I try to keep the gear moving so I don’t get the hole out of round. A couple moderately slow passes around the hole will knock the high points off the stair step and make the pen feel much smoother. You don’t need to get it perfectly smooth. Just knock down the edges and the pen won’t jump as it moves around the hole. You do need to be careful about keeping the gear perpendicular to the bit or you can take material off the rim of the hole and leave the ridges in the middle.
Smoothing the gear teeth takes two passes, the first with one of the medium barrel bits to deal with the outer portion of the teeth and then another with one of the smaller barrel bits that can fit down further between the teeth. The thing here is to watch that the gear is perpendicular to the bit so it takes a bit of material from the entire width of the teeth.
You don’t have to smooth both the gears and the rings. As long as the stair steps have been removed from one, the teeth will slide together smoothly. Imagine you had two staircases, one turned upside down on top of the other. They obviously won’t slide against each other very well. Replace one staircase with a sheet of plywood and the plywood will slide along the edges of the stairs. Same thing with the gears and rings. Doing both should make it a bit smoother but I haven’t found it necessary.
With all of these it’s probably a good idea to start doing it totally by hand until you have a feel for it and some confidence that you aren’t going to mess things up. Do a few holes and then try them with a pen. I think you’ll notice the difference, particularly if your gears are brand new. Ironically, the burr bits will probably leave a slight burr around the edges of the holes and gear teeth. Put the gear flat on a piece of paper and slide it around for ten or fifteen seconds. That will remove the burrs and make the gear feel smooth when drawing.
So if you’re seeking perfection, you might want to try what Jay’s been doing. The diamond burr sets even come in different grits, so a person could totally geek out getting the edges smoother and smoother. Or find out for yourself where the Law of Diminishing Returns applies. Feel free to share in the comments if you try this.
More from Jay Heyl coming soon.
I forgot to mention that the burr set I got was 400 grit. The slightly coarser 240 grit should also work well. I wouldn’t recommend going finer than 400 for this.
Thanks for this!
I can’t say as I’ve noticed this, but my eyesight isn’t that good. I wonder whether this problem is in the nature of later cutting acrylic? Should Aaron Bleakley or Ponoko be made aware and the problem addressed at source? Too late for those of us already using Wild Gears.
I’m a little daunted by taking a drill to a set I’ve paid £100 for! I admire your courage, talent dedication!
I use H4000 Silicone Spray when I notice any “little hang ups”. It has worked well for me so far. I also use the Silicone on the flat surfaces and it helps the ‘glide’ of the moving gears on the paper.
Direct from the manufacturer is the only place I’ve been able to find that and they want a ridiculous amount for shipping. Most other products seem to contain other ingredients that I’m not sure will get along with acrylic. Silicone lube sounds like a good idea if I can find the right product.
I’ve discussed the issue with Aaron. It’s not a defect so much as an artifact of the laser cutting process. ALL laser cutters work by moving in discrete steps along the X and Y axes. Very expensive ones move in smaller steps and would produce a smoother surface when cutting at angles other than directly along the X or Y axis, but the cost for using those machines would no doubt be considerably higher, driving up the price for Wild Gears.
I in no way meant to imply Wild Gears are deficient as they come from the manufacturer. The grinding of the holes and teeth on Wild Gears is a more extreme mod in search of perfection. During much of my career there was a push for continual product improvement and I’m afraid that has influenced my daily life as well. I’m always looking for ways to make things better, even if it’s only by a little bit. Aaron, I suspect, shares this ideal as evidenced by his recent changes to existing gear sets trying to make them better.
(Continued from above)
I was also very reluctant to take an abrasive bit to my Wild Gears. I wouldn’t have done so if the bit set hadn’t been so cheap or possibly of use for other things. I carefully did the first pen hole by hand, testing the feel and checking the roundness after each twist of the bit. If it had gone out of round or not clearly resulted in a smoother feel I wouldn’t have continued. It wasn’t until I’d done several holes by hand that I was brave enough to give the drill a try.
The stair steps from the cutting process will eventually wear down from normal use. Using the abrasive burr bits is just a way to speed up that natural process.
Out of curiosity, Jay, what was your career, since you mention it in the past tense? I was going to make a remark about your bifocals being better than mine, but refrained, lol.
I’ve noticed the irregularity more in the small gears than the bigger ones. Perhaps the inertia of the larger mass, and/or increased friction on paper, overrides the effect. I might try this on some smaller gears first. It would also be more noticeable with very fine-point pens, and less with pens having a larger barrell, kind of like the stair stringer example you mentioned.
Over time, the laser cutters will probably improve in quality, just as computer monitors, for example, are giving us better and better pictures as the pixels get smaller.
Meanwhile, it’s so much fun to explore the possibilities of what the gears can do.
I spent most of my career doing software design and programming. Interestingly, during the latter part I worked with high precision laser equipment.
My bifocals are worthless. I have to take them off to see up close. But this was less about vision and more about feel. With the larger holes in particular I can feel the ridges as the pen moves around the hole. A larger barrel would definitely reduce the effect.
I did some experiments where I used other gears as climbable obstacles inside a ring. This required the teeth to slide against each other as the gear moved from ring to obstacle and back. The ridges on the teeth became a noticeable issue and that’s when I started looking for a way to smooth them out. I started with a nail file and eventually ended up with the burr bits.
There are laser cutters with much finer control (stepper motors with smaller movements) but they are a lot more expensive. The ones used at Ponoko seem similar to most of the other online laser cutter services, about 0.1mm steps. They’re basically good enough for most cutting where extremely smooth curved surfaces aren’t required.
What worked well for me on smoothing the large holes was I took some 400 grit sand paper, cut into a smaller piece, rolled it into a tube and twist it around in the hole for a minute or so. It didn’t really make the holes perfectly smooth but it helped get rid of the ridges.
Good idea. It makes me think: I have some round files from when I used to make jewellery. I should try them – gently.