In our recent article, The Making of the WaterColorBot, we walked through the manufacturing process of the WaterColorBot, in which we make use of a number of specialized jigs, with varying levels of complexity. We also left a teaser:
“The winch is also assembled from laser-cut wooden parts. The lower part has the shaft collar that mounts to the motor shaft, and the upper part has two halves that disassemble for cord management. It turns out that the winding-drum part of the winch needs to be quite round and concentric with the motor shaft for smooth operation– smoother than we can get with the laser. We solve this with our very-most-complicated assembly jig….”
And here it is.
“Jig” may in fact not be the right word– it’s more of a cutting machine, and (if you squint your eyes enough) there’s just a hint of CNC hiding inside this manually operated tool.
Terminology aside, the jig/machine is based around the Vanda-Lay Drill Press Plus, which we wrote about earlier this week. The Drill Press Plus is a precision drill press type fixture for Dremel and similar rotary tools, and which we attached to a heavy base made of MDF. To its aluminum base plate, we added a pair of tapped holes that allow us to bolt down a wooden superstructure. The superstructure has a single stepper motor, pointed upwards and driven by the same “EBB” motor controller that we use on the WaterColorBot itself.
Prior to cutting, the outer “winding-drum” of the winch — the upper cylindrical surface in this photo — is a typical dark brown laser-cut wooden surface.
We mount the winch on the shaft of the vertical stepper motor, and spin it around while we lower the (also spinning) Dremel tool with the vertical feed of the drill press. This is a lot like using a power-fed rotary table to cut an outer surface on a vertical milling machine.
Unlike doing this on a 4-axis milling machine, it takes a steady hand to gently lower the feed as it cuts the edge of the winding drum.
From a user’s perspective, one of the really cool things about this machine is that when you’re done cutting, the stepper motor always stops with the set screw (indicated by the diamond) facing towards the front, so that you can easily remove the winch. That’s straightforward because we always command the stepper motor to go an integer number of turns. (And it’s just a hint of CNC, if you squint your eyes.)
After cutting, we spot check the winches to make sure that the diameter is within tolerance: 1.125 ± .005″. Typically, it’s within 1-2 mils.
In order to achieve that kind of precision, it turns out to be necessary to use much better cutting tools than the kind that come with Dremel tool sets. This is a 1/8″ diameter solid carbide 2-flute tool with straight flutes (in a red, plastic holder) that works wonderfully for this application. Spiral flutes tend to cause some side forces and/or lift that cause a loss of precision in our small tools.
Here is the side by side of a winch before cutting, and after (with its cord-winding rivets pressed in).
And finally, you can watch the process in real time, in the video embedded above, or on YouTube, here.
By popular request, we are releasing the design files for our famous 555 Footstool project.
The design is made from 23 pieces of 1/2″ hardwood plywood, laminated together, in a sort of manual 3D printing process.
While in the course of a recent project, we ended up needing a machine to perform a particular operation. The operation was one that falls squarely into the (rather narrow) set of things that you would expect a “Dremel drill press” to be ideal for. And so (1) we got one, (2) found that it wasn’t very good and then (3) found an excellent alternative: The Drill Press Plus by Vanda-Lay Industries.
The Dremel “Workstation” drill press
First off, what’s up with the Dremel version? The model 220-01 Workstation is Dremel’s current drill press offering. And while it is inexpensive (~$45) and basically functional, it leaves a lot to be desired. To be specific, precision.
The first issue is that the Dremel tool is affixed to the Workstation at only one place, which is the wide-diameter hex nut visible just above the collet nut that holds the tool. You can see that in the photo above, about 1/3 of the way up. The mount is made of semi-rigid plastic, and has a long lever arm to the main vertical shaft. Consequently, the Dremel tool flexes (rotationally) quite a bit about that mounting point, leading to both position and angle variation in any hole that you might want to cut.
The second issue is that the vertical sliding mechanism is poorly designed, which leads to a lot of horizontal slop in the machine. The vertical slide consists primarily of an unground steel rod, constrained by two brass set screws that are set into semi-rigid plastic fingers. The combination of the rough rod and the plastic fingers is particularly poor: Either the set screws are loose enough that the travel is smooth but the motion is very sloppy, or they are tight enough that there’s little (but still some) slop and the travel is overconstrained.
The Vanda-Lay Industries Drill Press Plus
Certain that there was something better out there, we searched for, found, and ordered the Drill Press Plus ($119 + S&H) from Vanda-Lay Industries, which showed up just a couple of days later. The Drill Press Plus is exactly what we had hoped the Dremel Workstation would be: a simple, reasonably precise, and solidly built drill press for rotary tools.
The Drill Press Plus is made of machined aluminum, with 1/2″ vertical steel shafts, and springs included. It is also a very simple machine. For example, rather than using a rack and pinion for the vertical feed travel, there is a simple cam mechanism whereby the lever itself presses the arm down.
Vanda-Lay makes a number of similar machines (such as the Acra Mill Plus) based on the same basic platform, and that seems perfectly credible, based on what we’ve seen. This machine has reasonably good rigidity and low slop for a machine its size, thanks to solid construction. (It’s no Bridgeport mill, but of course it only weighs a few pounds, not a few tons.)
One of the things that it does very well is to clamp the rotary tool solidly about its midsection with not one, but two solid aluminum clamps.
There are a few little things that we would recommend as ways to improve yours, once you get it. First (and foremost), you need to grease the shafts. The steel shafts slide in plain-bearing holes cut in the aluminum, which are excellent tight-tolerance guides, so long as they are greased. If you don’t grease them, they don’t really slide.
Second, you might consider what we did, and add two set-screw style threaded ball-end spring plungers,10-32 x 1/2″ long with stainless steel roller balls to the help constrain the shafts. These go into the threaded holes meeting the flat side of the D-shafts on the Z-arm, and are visible as the two brass-colored screws. These take out what little slop is left in the vertical feed motion.
Third (and slightly more so than the Dremel version) the Drill Press Plus really wants to be bolted down to a table to have enough mass and stability to work well. The included aluminum base plate is nice, but not quite wide enough or massive enough to hold it in place while you use the tool.
Since we didn’t want to permanently take up bench space with it, we cut out and bolted it to a heavy, wide platform, made of two ¾” thick pieces of MDF glued together. That turned out to work incredibly well, allowing us to set it on any bench when we need it, and use it there.
We’re running a Thanksgiving sale in the shop: save 20% or more on selected kits and components, Black Friday through Cyber Monday with free US shipping for all orders over $75.
Despite what you might guess from the name, our Egg-Bot kit is not just for eggs. In fact, it turns out to be a pretty freaking amazing machine for decorating and personalizing your own Christmas ornaments!
Today we’re releasing the “Eggbot Holiday Super Pak” — a set of Eggbot-ready holiday ornament designs to give you a head start. The set includes the designs above and many more. It’s free, available for download here (2.2 MB .zip file), and will be periodically updated as we add more designs.
Read on for some additional tips and tricks for using ornaments in the Eggbot!
Christmas ornaments up to 4″ (100 mm) in diameter will fit in the Eggbot. We like these satin-finish glass ornaments, as the frosted finish is easy to grip, holds ink well, and gives excellent contrast for ink. By contrast, shiny silver balls and transparent balls make it much harder to see markings. Sharpie markers work extremely well on these, producing vibrant, long-lasting colors.
There’s a neat way to mount an ornament in the Eggbot, which is to remove the little cap and hanger that come with it. Both come out with a gentle, straight pull.
Then press the ends of the clip to pull it out of the cap. Set the clip aside, and place just the cap back on the ornament. That leaves you with a nice cap that you can use to grip the ornament in the Eggbot.
Then, mount the ornament in the Eggbot, with the pen-motor shaft facing directly towards the fattest part of the ornament.
In order to provide the most grip on the ornament, it’s usually best to orient an ornament’s cap towards the tailstock as shown above. But, since that’s the opposite of how eggs and things are normally oriented, your patterns will end up upside-down on the ornaments!
To fix this, you can either (a) flip the pattern upside down or (b) use a clever trick: In the “Options” tab of the Eggbot interface, check both boxes, to reverse the direction of each motor. Then, your designs will all print right-side up.