Friday, September 8, 2017

Her Own Private Themyscira

When the recent Wonder Woman movie came out, just about every woman I know wanted to go to Themyscira right now (except my mom, who doesn't go in for movies), and I suspect a good many of them would have wanted to stay. But, of course, it's difficult to get plane tickets to places that don't exist, so none of them got to make the trip.

But I got to thinking about how I could get my lovely and talented spouse as close to Themyscira as I could. The answer was a 3d-printed frame. It was back to the Classical architecture of my grad school days: fluted Doric columns, a simple entabulature (those are Ws instead of triglyphs, of course), and so on. Finished, of course, with a little paint to give it an aged look and some terra-cotta-colored "roof tiles."

 From behind, it's hollow.

And there are cutouts on the top and right side.

They're sized to snugly fit a small digital picture frame while leaving the ports and controls open.

It contains a memory card with screen shots from the movie as well spots on the Amalfi coast on which the movie Themyscira was based. The result:

A slideshow providing a window to the island of the Amazons. It's not a one-way ticket to a mysterious island, but it does fit nicely on a table or desk. And certain persons to whom I am married seem to like it.

And it just now occurs to me that I could do the same thing for her on a Rivendell theme...

Saturday, June 17, 2017

Secretary Desk: Gettin' Jiggy With It

One of the many items of furniture we have that doesn't hold enough is a cheap, unfinished wood secretary desk, which we've had for somewhere between 15 and 20 years. It's not bad as such things go, but it is too small. So certain persons to whom I am married suggested that I could build a bigger one. And so I did. I pulled out all the technology for this project, since I am a terrible carpenter if left to my own devices.

Peg Jig

I wanted to used dowels rather than screws to hold the structure together. So how do I get all of those peg holes lined up? 3d printer to the rescue. I worked up a little t-shaped piece the same width as the thickness of my boards and evenly spaced 1/16" holes in it. With that in place, I could drill pilot holes in the edges of the upright boards and matching holes down through the thickness of the horizontal ones. Those were followed by a 1/4" bit and then matching dowels.

Adjustable Router Template

I decided to cut dado joints for the internal shelves in the lower cabinet. But how? That requires absolutely straight grooves cut at exactly the same height across the boards for both sides. I started by clamping the boards together side-by-side and penciling lines where I wanted the shelves to slide in. Now, if you're a competent carpenter, you just need to set a fence in the appropriate spot and use that to semi-freehand a groove with your router.

I am not a competent carpenter. Back to the 3d printer, but for something more elaborate. I've got router guides and I've used router templates with some success in the past, but how to make that work for what I'm doing? And here's where I decided to make a multi-purpose device. I modified the design for a set of micrometer calipers with "feet." Then I ripped a four-foot piece of quarter-inch plywood into strips about six inches across. By screwing the calipers to the ends of the plywood strips, I could very precisely adjust the separation of the strips, which were thin enough to make a very good template for the router. In this case, the gap needed to be no wider than the template guide, but I could adjust the gap to rout out a much larger area if need be.

(And fortunately, this worked out in practice about as well as predicted in theory.)

Roll Top

The really fancy part of this is a roll top for the top section. In theory, it's pretty easy. For the opening top, you get a bunch of thin slats of wood (which was a piece of thin plywood run through the table saw a quarter inch at a time) and glue them to a piece of fabric. Not too difficult. But then I need to cut mirror-image curves for the top part of the cabinet and parallel mirror-image grooves inside their radius for the flexible front cover to move through. Yeah, no way I'm doing that. CNC work.

The black lines cut all the way through. The gray lines are grooves a half-inch deep in the 3/4" lumber. The top curve is for the roll top, the horizontal bit in the middle is to keep cubbyholes in place. A little trimming the ends of the slats and sanding the inside of the groove and it fits together surprisingly well.

So Finally

Assembly (with 3d printed elephant heads as hardware to open the roll top), some stain, and a zillion coats of shellac later, it looks like this.

But the important thing is that it contains about 50% more than the old one.

Saturday, June 3, 2017

Dice Trebuchet

I blame John Kovalic.

(Go read the strip now before I ruin the joke any farther. Back now? OK.)

I've got a few dice towers, but a dice trebuchet? Not so much. So clearly, I needed to make one.

The frame, made from 3/4" birch plywood, is easy. A little CNC work for the supports, routing out spaces for 22mm bearings at the top, cutting through all the way in the center to make room for the axle to move freely, and some sockets in the base for the uprights. A little sanding and it all fits together nicely

The other wooden parts are mostly made from standard stock. At the center of everything is a short section of solid 3/4" square birch. It has 5/16" holes bored at the ends and all the way through the middle. Why 5/16"? Because that's almost exactly the diameter of the 8mm holes in the centers of the bearings. A 5/16" dowel for an axle fits very snugly. Since I've got it around, more dowel forms the throwing arm and the counterweight arm. I'm increasingly using the 3d printer to create jigs and other placement aids, and this project was no exception. All drilling was performed with the use of a jig with a 5/16" bore and a small frame allowing it to be centered on a 3/4" width.

Then it's off to more 3d printing. The basket at the end of the throwing arm is 3d-printed and presents a vastly easier solution than cobbling together a more realistic but teeny sling and release mechanism. It's big enough to accommodate 3d6 for any reasonably sized dice if you're playing GURPS. I assume it'll hold die for other games, but why would you want to play those?

The counterweight is, appropriately, a small dice bag, so it can serve as an ammunition supply as well. There's a small hook on the counterweight end of the arm to hang it off of, but it can be taken off to add or remove dice, changing the force of the projectile. If dice aren't heavy enough (and, to be honest, they probably aren't), those little glass stones can be used which double as level markers for games like Munchkin. 

And how effective is it? It's not bad:

That's a fairly standard d6 being propelled across the length of a fairly standard dining table. With a bit of a backstop and/or a smaller counterweight (this was using a stone icosahedron), the trebuchet could actually be used to roll dice. Or to destroy your enemies.

UPDATE: For the benefit of those with CNC machines, I've published the Easel design on Inventables, so you can make your own.

Sunday, March 26, 2017

Steampunk Nautilus Stylus

More stylus sillyness in the style of the iPlume. To reiterate: a stylus for a touchscreen device is basically a conductive stick. It needs a conductive tip to touch the screen and a conductive body to carry the current through you. Anything conductive which touches you anywhere will do.

I saw this rather nifty design for a finger-mounted pen and figured I could capitalize on that. The styling was rust paint (I do enjoy that stuff, don't I?), a couple of fins and some gears, which just happen to fit on the mountings for the screws holding the parts together, and if they weren't glued in place, they'd rotate just fine. Too late, I thought of ways to preserve that motion. Oh, well; maybe some other time.

The way this works is by replacing the ink cartridge with a copper wire. The twist of wire at the front is ground down a bit, providing the necessary quarter-inch surface required for the screen to read it.

But rather than directly touching the wearer's finger, the wire passes through the body of the housing and touches the back of the wearer's hand. And it does, indeed, work. Not well, though. I may fit some spongy conductive rubber over the end or something so that the tip smushes a bit on the touchscreen, both for increased area and to protect the screen from scratches.

Yes, More Furniture

The additional bookshelves we need apparently aren't going to build themselves, even though I've given them every opportunity, so here and there, I have to take action myself. Certain persons to whom I am married require more immediate access to unread books, keeping the queue of stuff to read close at hand and not confounding them with books already read. Solution? Combination footstool/bookcase.

Unlike the game cart, I went to the CNC for this. I used an awful lot of dado joints, but in a far more sophisticated way. The basic structure is simply a cube open on two faces, but internally, it's more complex

One side has two shelves sloped at a 10 degree angle to improve visibility from above, just tall enough to hold regular paperbacks. The other has a large shelf sloped shelf and a small horizontal one to hold whatever else needs holding. Going much larger than I usually do, I used a 1/4" bit on the router, which meant I could slide in the 1/4" boards used for the shelves, using a little glue and some tiny nails to secure them.

As ever, it's a couple of days for finishing the wood, some tiny wheels on the bottom, and some foam and velvet for the top.

It doesn't hold nearly enough books. Nothing ever does. But at least it holds most of the books she's currently hoping to read.

Tuesday, February 14, 2017

Crisis on Infinite Mirrors

Certain persons to whom I am married like DC comics and those infinitely-reflecting mirror things. This suggests certain Valentine's Day presents.

Infinity mirrors, it turns out, are pretty simple. You need lights around the inside edge of a box, which is really easy to do these days with LED light strips. The ones I got could even be snipped to desired length. The bottom of the box is mirrored (I used inexpensive glass mirror tile). The top is half-mirrored. That's a little trickier, but there's inexpensive window insulating film for that. The only innovation on my part was firing up the CNC machine to engrave a bunch of superhero logos on a sheet of acrylic to use as the top. That was a delicate operation. The carving required very, very shallow cutting, so it was very sensitive to the slightest bend in the material. Sandwich the semi-mirrored film between two sheets of acrylic (one engraved), assemble, and:

Thursday, January 19, 2017

Gotham by Dice

We've been playing a certain amount of Steve Jackson Games's Batman dice game. It's an excellent game (any competitive game I can get my lovely and talented spouse to play is a good one), but a little sparse by our standards. What's the natural thing to do? How about a custom dice tower.

This is mostly bricolage, as we structuralists call it. About a third of the buildings around the dice area are from this skyscraper chess set. The remainder are from a Sim City play set and some Hong Kong apartment blocks. The manhole cover is...well, a manhole cover the Gotham City utilities people use. The dice tower proper is a model of the KOIN tower, significantly resized and hollowed out. I added a couple of ramps for the dice to bounce off of and an arch for them to roll out.

The only thing I really designed was a base for all the parts, basically the base of the main tower plus an 80mm diameter ring at the end of the ramp. All the towers got spritzed with stone texture spray paint, while the manhole cover got the Modern Masters iron paint and rust activator. I really like that stuff. A little cyanoacrylate to hold everything together and we're off to the races. And now we'll have something far more interesting to bounce our dice off of next time we play.