Walking Wooden Poodle Automata / Karakuri Machine

jchismar Poodle Dog Automata Karakuri

Yesterday was my super-sweet standard poodle Fleur’s thirteenth birthday. To commemorate the occasion I dug in and built an automata in her likeness. Loosely defined, an automata (or Japanese karakuri) is mechanism that imitates the movement of a living creature. This project has been on my to-do list for several years and I thought it was about time I gave it a go.

The mechanism is based on a popular design that’s been around for a while. In the early 2000’s Theo Jansen, either refined or invented the linkage for his very popular wind-powered walking machines. Each part of of Jansen’s mechanism is carefully specified, elegant and mind-boggling in it’s function. Me? Well, I just sort of guesstimated the dimensions and ran with it.

jchismar Poodle Dog Automata Karakuri

I first made templates out of cardboard of each part. Each template was transferred to 1/8″ plywood and cut out using a scroll saw. The holes for the pivots were made with the drill press. I then used 1/8″ wooden dowels to assemble the mechanism.

Assembly was tricky at times because I didn’t have an assembly schematic. I just went with the flow. I made sure the dowels were plenty long to allow me to put the puzzle together on the fly. Once everything was in place the excess was trimmed from each dowel.

All in all I’m pretty impressed with the complete mechanism. This was the first, but certainly not the last machine of this style I build. I already have tweaks I’d like to try to give this girl a little more life. Watch the machine in action in the video below.

How to Design and Make Automata or Whirligig Gears Using the Power of Geometry

“…Chemistry is not an exact science” ~Mario Andrada

jchismar How To Make Wood Gears

In this post I will do my very best to simplify the process of designing and making gears from wood and other materials. The process to build a simple Spur Gear and Pinwheel Gear will be explained.

Thanks to my background in 3d animation I have a rudimentary understanding of geometry and mathematics. I would love to be a math magician but like many people I get lost with anything beyond algebra. Thank goodness for the internet and calculators!

jchismar N-Gon Automata GearAs my math magician friend Charlie reminded me, “To get the teeth to mesh, the spacing BETWEEN the teeth need to be the SAME on all gears.” With this in mind, using the n-gon is ideal to design a gear, the spacing between each vertex is uniform. Simply stated, an n-gon is a polygon with “n” amount of edges. The image to the left is of an eight sided n-gon. The n-gon has two radius measurements: circumcircle (rc)and incircle (ri). If you need a refresher, the radius is the distance from the center to the outer edge of the n-gon, the diameter is the complete distance from side to side (through the center). Vertices are the angular points where each edge meets (the white “edge” arrows point to vertices).

When designing gears we will focus mostly on the circumcircle radius (rc), the vertices are positioned along this radius.  The vertices will become the teeth of our gears.  If the desire is to use a gear to turn another gear uniformly each gear will be identical resulting with a 1:1 ratio. To use a drive gear to rotate a second gear at half speed the second gear needs twice as many teeth as the drive gear, a 2:1 ratio.

Below I have included a calculator to do all the hard stuff for us.

Say you want to make a pair of gears with a 2:1 ratio, the drive gear turning twice for each turn of the second. You also want the drive gear to have a 1″ radius (2″ diameter). You also want the teeth to be separated by 0.5″. This is easily accomplished with the use of the above calculator. The calculator’s default settings are Edge Length (a): 0.5 and Number of Vertices (n): 8 resulting with radius (rc)  of 0.6535. This radius is just over half of what we desire. We can’t change the Edge Length because in this example we want the tooth spacing to be .5″. Instead, increase the Number of vertices to 12. Now radius (rc) is 0.9664 just under the 1″ radius we were looking for. Perfect!

The 2:1 ratio requires the second gear to have twice as many teeth. This doesn’t mean twice the teeth makes the gear twice as large. Let’s see. In the calculator change the Number of Vertices to 16, doubling the amount of the drive gear. Radius (rc) is 1.9162.

This is important! When I started designing gears I was under the impression that to double the ratio, the radius simply needed to be doubled. This is NOT the case (thanks Charlie)! Let’s examine our calculated radius values:

  • 12 vertices Drive Gear (rc): 0.9664
  • 24 vertices Second Gear (rc): 1.9162

That’s double, right? No. It’s not double. By doubling the drive gear radius (rc), 2 x 0.9664 the product is 1.9328, a difference of 0.0166. Doesn’t seem like a huge deal, but a .0166 error can, in fact, impede the smooth operation of the gears. To emphasize this point let’s examine a more extreme 10:1 ratio example.

  • 12 vertices Drive Gear (rc): 0.9664
  • 120 vertices Second Gear (rc): 9.5552

Multiplying the 12 vertices Drive Gear (rc): 0.9664 by 10 (0.9664 x 10) results with a product of  9.664. That’s 0.1088, or a tenth of an inch, larger than calculated (rc) value.

Making Spur Gears

Right about now you’re probably thinking, “Hey John. I thought you were going to show me how to make gears, not bore me to death with math.” Well, you’re in for a treat, let make some gears! We’ll start by making a pair of spur gears: one 1:1 and another 1:2. A spur gear is a gearwheel with teeth projecting parallel to the wheel’s axis, this is the sort of gear everyone is familiar with. For this example we’ll be making wood gears. You’ll need paper, wood, glue, drill (or drill press), saw, an accurate caliper gauge and a quality pencil compass.  If you don’t own these instruments you can find them at any hardware store – or you can be like me and score vintage beauties at flea markets and estate sales. Cheap tools may work, Harbor Freight – cough, cough, but I often find cheap tools more frustrating than productive.

jchismar How to Make Wooden Gears 01
Step 1

Step 1: Layout the Gear

Laying out the gear is the most important task of making your own gears. I own a few sets of old drafting tools I picked up estate sales for a few dollars. The compasses in these sets are fantastic quality and several of them have an adjustment lock. I use several compasses, and once their settings are perfect, I don’t change a thing until every gear is marked on on wood.

First, calibrate the compasses by drawing on paper. To layout the drive gear use a pencil to draw a small dot on paper, this is the center of the first gear. Set your caliper gauge set (rc): 0.9664 (or as close to this value as the gauge allows) match the pencil compass to this value. Place the compass needle on the pencil center mark and draw the circle. Reference your caliper gauge from the center of the circle to ensure the drawn circle is correct.

Set the caliper gauge to the Edge Length (a): 0.5 and adjust a second pencil compass (preferably locking) to match. Using the circle as reference, draw ticks across the circle (rc) at .5 intervals. When you’ve gone all the way around the circumference your last tick should match the first tick exactly. Refer to the Step 1 image to see my terrible first result (red circle). If it’s not perfect, something went amiss in your settings. You’ll need to start again. This requires patience and practice. The width of the pencil line complicates creating accurate marks. You’ll need to get a feel for the process.

Once you’re comfortable laying out the gear, layout the pattern for each gear on the wood you’re using. This also may require a few tries. Working on this example required about two hours to layout eleven gears from start to finish.

jchismar How To Make Wood Gears 02
Steps 2 & 3

Step 2: Cut Out the Gear

Now you’ll need to cut the round gear from the block of wood. Generally I use the band saw or jigsaw for the task. You can use whatever works best for you: hand jigsaw, Dremel, router, etc. Cut to the outside of the radius (rc) line you created with the compass. Try not to remove the line! Once the gear is roughed out, use a disc sander to shape the circle precisely to the line (bottom left Steps 2 &3 image).

Step 3: Drill a Hole

I generally use 1/8″ wire to mount the gear to the project. The wire serves as the shaft for the gear to rotate about. I use an 1/8″ drill bit in my drill press for the task. Drill an appropriate sized hole centered on the depression you make with an awl. This is the middle of the gear.

After the gear is complete I use a small round file to enlarge the hole to make it rotate more easily on the wire shaft. But that’s the last step!

jchismar How To Make Wooden Gears
Step 4:

Step 4: Add the Teeth

This is where personal preference, practice and experience comes into play. For this example I will be using poplar that I’ve planed to .125″ thickness. The strip of .125″ poplar is ripped on the table saw to .75″ width. Individual teeth are crosscut from the strip to a .75″ length. Each tooth is .125″ x .75″ x .75″.

I’ve constructed a miter bar jig for the table saw to hold the gear while cutting a dado for each tooth around the the gear. The dado I cut is .25″ deep and .125″ wide.  With the table saw jig I am able to center the vertex ticks drawn in Step 1 spaced at .5″ around the gear. I center the tick to the blade, cut the dado. The gear is rotated to center the next tick and the next dado is cut. This process continues until each required dado is cut.

I squirt out a puddle of wood glue on a scrap. I dip the point of a wood skewer (the grocery store kind) into the glue and spread glue into a gear dado. Then, using the skewer, add a little glue to the end of a tooth square. It is important to insert the tooth square into the dado so the wood grain is perpendicular to the dado. If the tooth is attached with the grain parallel to the dado you run the risk of the tooth breaking with the grain.

Continue this process until you’ve completed the gear.

Step 5: You’ve Made a Spur Gear!

Congratulations on making your first gear! Repeat these steps for the second gear (keeping in mind the second gear is larger: 24 vertices Second Gear (rc): 1.9162).

Making Pinwheel Gears

Let’s say your project requires the drive shaft to power another element or shaft at a ninety degree angle. Enter the Pinwheel Gear. You’ll need wood, drill (or drill press), saw, an accurate caliper gauge and a quality pencil compass.

jchismar How To Make a Wood Pinwheel Gear
Step 1: Layout the Pinwheel Gear

Step 1: Layout the Gear

The layout for differential gears is the same as spur gears above. Use an awl to mark center. Then draw the circle with radius (rc) using a compass. Use the compass again to draw evenly spaced vertex ticks around the circle. Because we’ll be using nails as the teeth on these gears we’ll need to draw another larger circle outside radius (rc). In this case radius (rc) is 0.9664, I generally add an eighth of an inch (0.125) resulting with a radius of 1.0914.

Step 2: Cut Out the Gear

Cut the gear to the outside of the largest circle. Then sand precisely to the line.

Step 3: Drill a Hole

This is exactly at Step 3 for the spur gears. I drill a 0.125″ hole centered on the awl mark.

jchismar How To Make Wood Pinwheel Gear
Step 4

Step 4: Add the Teeth

I use the drill press to create an appropriately sized pilot hole at each vertex cross tick. The pilot hole should not be completely through the gear, only as deep as the nail will be driven into the wood. Here, I’m using three penny nails. Start the nail in partway then place a scrap of wood against the nail as a depth gauge. Then hammer the nail until you’re hammering the wood scrap. Continue adding nails in this fashion until your pinwheel gear is complete.

Step 5: You’ve Made a Pinwheel Gear!

You’re an expert gear maker now. Let your imagination run wild! I’d love to see the mechanical creations you’ve built.

A Note About Gears

I started the post with a quote that originated from the 2016 Rio Summer Olympics, “…Chemistry is not an exact science…” This was an Olympics official’s response to questions pertaining to why the pool smelled rotten and the water was green. I’m here to say Chemistry is and exact science. What does this have to do with making gears? Well, making gears is an exact science also. This post, however, is the groundwork to understand how to construct gears, not exact science.

Earlier I posted about building a Pegasus whirligig kit. Assembling the kit was a fun distraction, but I honestly didn’t learn much from the task. I’m a tinkerer. I enjoy spending time considering how to make things, and how things work. I find little satisfaction in following a detailed design – robots do that. I like to build the plane while it’s in the air, as they say. It’s fun to start something, and troubleshoot and modify along the way. This is how I gain a full understanding of the project. I often build many test projects before I tackle the actual build.

Creating mechanical machines is challenging. There is a lot of trial and error involved for the novice (myself included). There is more to designing precision gears than I’ve mentioned in the post. I’ll be honest, I don’t understand most of the technical mumbo jumbo, big words like dedendum, addendum, clearance and working depth versus whole depth. If things don’t work – that’s normal. It’s an entertaining learning experience. I personally find as much enjoyment in the flops as in the successes. When the project is complete, the challenge is over – and that can be a bummer.

Making gears using this method will require trial and error. The space between the gear positions will be an issue. The heads of the nails and the lack of a taper on the ends of the spur gear will likely cause these gears to jam. Consider using a metal cutting wheel to cut the heads off the nails – and taper the metal end. Also consider sanding a taper on each tooth before assembling the spur gear.

For those makers that want a detailed, guaranteed plan you can visit http://geargenerator.com/ to design and print precise gears. This post will get you started making functioning gears. Please take what you learned here, build on it and make it your own. There’s more than one way to make a gear.

I am planning a follow up post regarding making wooden gears. There will be more information and project ideas to be found in the follow up post. In the meantime, be creative and have fun.

Mize Mini-Mize Whirligig Automata Pegasus

Mize ME07J Mechanic Series jchismar

As you probably figured by now, I can’t sit still. Yes, I have a zillion started projects in my workshop and plans for more in my mind and hard drive. I may get around to finishing some of these projects but I have such little time! I’m not a humongous fan of 3d printing and laser/cnc cut stuff, but every once in a while I scratch the creative itch and dabble with this sort of thing.

I decided to purchase a mini automata whirligig kit manufactured by Mize, based in South Korea, online for $21.00 including shipping. There wasn’t a whole lot of information about this item in the description, but judging from the single image of the item it looked like it was going to be small. The package arrived from South Korea and I thought it was a thick holiday card, roughly 6″ x 9″ x .75″.

Mize Mini-Mize Pegasus Instructions

I opened the package and looked at the instructions. Yup, as assumed all the instructions are in Korean. Not a problem though because the images tend to explain everything clearly (enough). Curious, however, I photographed the instructions and uploaded them to i2ocr to translate. I don’t think it translated too well. Here’s a few selections from the translation:

  • The city is divided into cities
  • Excessive stress on the stomach can damage it
  • You have to do the complexion
  • I want to be a transit agent, too.
  • Sennepusa Seeking Confession | Do not be sick
  • The lungs are soaring
  • Even if I left you, I would like you to be my best friend

For real. I can’t make this stuff up.

jchismar mize pegasus translated

Lucky for me I work with Heeman, a talented Korean designer. Heeman was kind enough to translate the pertinent information in the image above. Thanks!

jchismar Mini Mize Pegasus

jchismar wood automata gears
A few gears from the project

Above are the three panels of parts that create the project.  Along with the instructions this is everything in the package. Excited, I retrieved my Loctite Go2 Glue, a toothpick and a paper towel. I reviewed the assembly instructions for the first few parts. I carefully removed the necessary parts from the panels by first scoring each sprue (the little piece of material holding the part in pace on the panel) with an Exacto, then carefully nudging the part free.  After test fitting the parts together I squeezed a small puddle of glue on a scrap of paper, applied a small amount of glue to the joints with a toothpick and reassembled.

The image at the top of the post displays the assembled crank box and completed project. This was an enjoyable and easy project to build. It’s important to be patient and clamp the pieces together (when possible) as you wait for the glue to cure between steps. I’ll admit, when I was attaching the pegasus to the gearbox, pretty much the last step, I carelessly broke the propeller off the gearbox. Luckily a dab of super glue came to the rescue and worked flawlessly.

I’d be remiss if I didn’t say the pegasus whirligig is not suitable for prolonged outdoor use. The material is MDF or something similar. I am surprised at how smoothly the mechanics operate because the drive shafts are simply square cut MDF material positioned in round holes. Birthday cake candles are provided in the kit. These are used to lubricate the moving parts. The lubrication the candles provide also works much better than I anticipated. The video clip below is of the complete kit operating outside in relatively gentle gusts of wind. Most likely I will be purchasing more of these Mize kits in the near future.

Wooden Toy Train Whistle Made With Table Saw

“I believe don’t start if you’re gonna quit”~Eric Church

jchismar wooden toy train whistle

I became inspired after building the Mini-14 Street Organ to learn about making wooden whistles for musical gizmos. I figured a good place to start was to build an old fashioned wooden train whistle toy. Ya know, the kind of thing kids buy at a gift shop to drive everyone around them crazy for days. A quick internet search revealed plans for the project on The Woodcrafter Page.

The Woodcrafter whistle required drilling four 7/16″ holes into a block of wood: at lengths 4 1/4″, 4 3/4″,  6 1/4″ and 7 1/4″ and  and plugging up the whistle end with 1/2″ length of dowel. Well, I don’t own a 7/16″ drill bit that’s 7 1/4″ long – and I don’t feel like buying one. I also didn’t feel like rigging something up to drill a straight hole to that length. I turned my attention to figuring out a way to convert that design to something that can be made with a table saw. I started by calculating the spacial volume of each whistle.

7/16" Hole Length My Volume Calculation Correct Volume
3.75" .52 inch^3 .56 inch^3
4.25" .59 inch^3 .64 inch^3
5.75" .82 inch^3 .86 inch^3
6.75" .97 inch^3 1.01 inch^3

The length of the hole in the table above has subtracted 1/2″ from each depth because of the inserted whistle dowel plug. For starters, my calculations are incorrect because I subtracted 3/4″ from the length, plus I made a few extra errors. For my train whistle I used my volume calculations.

Toy Wooden Train Whistle
Whistle #1

The first whistle design fixed the length of the whistle to 2″ and height to .5″. The width varied based on matching the spacial volume. Fun fact: Confirmed in hindsight, the length sets the pitch of the whistle. In the case of this whistle there are four whistles and each one simultaneously sings out a D6 note, or 1174.66 Hz. You can hear this whistle by playing the sound below.

jchismar wooden wood toy train whistle
Whistles #2 and #3

So the first whistle wasn’t so great. I learned the length of the whistle determines the pitch. The second whistle I built fixed the height and width to .5″ and the length was adjusted to maintain my spacial volume calculations. The lengths are as follows: 2.08″ 2.36″, 3.28″, 3.88″. This whistle sounds more like a train whistle clearly making three frequencies (show in image at top).

Since I was in the zone I also built a third version fixing the height and width to .5″ and the lengths provided from the Woodcrafter Page. This whistle basically sounds two frequencies, but mostly sounds like one low note. Listen to whistles #2 and #3 here:

What did I learn? This lesson taught me I have a lot to learn about whistles. The Woodcrafter design suggests there should be four frequencies produced, in pairs of two close frequencies. I know why the first whistle only sounds one note – because all for whistles are the same depth. The second whistle may actually produce four frequencies, the two lower frequencies close to each other. I’m uncertain why the fourth one appears to only sound two frequencies. At least two of the whistles constitute the strong lower frequency because it’s wide and strong.

I have more ideas to explore when I revisit the project. And I think I’m going to consult with Charlie, my engineering and math magician friend, before diving in.

How to Draw a Spiral and Make a Home-made Top

The Newark Maker-Faire is less than two weeks away and I’ve been hard at work finishing up my exhibit Home-made Toys for Girls and Boys. This past weekend I continued assembling toys for display at the show. One such toy is a spiral top described by A. Neely Hall in his book about home-made toys. I created this short video describing how to draw a spiral and build the top.  Get your craft supplies ready and I’ll see you at the Newark Museum Saturday April 30.

An Electric Toy Shocking Machine


jchismar electric shocker toyThe Toy Shocking Machine, in all honesty, is a primary reason I chose to construct projects from the 1915 book Home-Made Toys for Girls and Boys for the upcoming 2016 Newark Maker Faire. The innocent nostalgia transports to simpler times when children were encouraged to challenge themselves and explore their world without restraint. Maintaining youthful spirit I imagined owning a device to shock myself, friends, family and strangers for entertainment. I’m old enough to remember similar devices making a splash at amusement parks and science class.

With giddy anticipation I started constructing the heart of the device, the induction-coil. The coil consists of two windings of different gauge wire around an iron bolt. A rapidly interrupted flow of electricity is applied to the central primary coil to create an oscillating magnetic field which, in turn, creates high voltage across the outer secondary coil. The high voltage discharges between the two ends of the secondary coil in the hands of a volunteer.

jchismar shocking toy interupter
Electricity Interrupter #1

In hindsight it’s easy for me to parrot the above information and sound as though I know what I’m talking about. I enjoy tinkering with hobby electronics however my understanding is often limited. When I attached the coil to a battery I was baffled as to why it wasn’t shocking me. Confused, I texted electronics genius friend Charlie England. He responded “…you have to apply voltage and remove it very quickly…” I hastily constructed an interrupter as described in the book. Turning the crank created an entertainingly loud racket and a few sparks, but nothing shocking from the secondary coil.

Charlie suggested testing the electromagnetic properties of the coil. I grabbed a small washer, verified it was steel with a real magnet and applied power to the coil. Nothing, the washer fell to the table without hesitation. The only thing that made sense was to apply more power (amps). Working in increasing intervals I finished with two 6-volt lantern batteries in series attached to the coil. No electromagnet but plenty of heat – which is undesirable. Defeated, I informed Charlie I was going to make another coil. He responded with four words, “Send me the coil.” Yessir, the coil was packed and on its way the following morning.

jchismar shocking toy
Electricity Interrupter #2

After receiving the delivery Charlie went to work testing my induction coil. The coil only created a 90 volt spike using a 10 volt power source. Charlie determined the secondary coil needed triple the amount of wire layers to generate a palpable shock. Charlie also designed and created an interrupter circuit employing a proximity switch. It was left to my imagination on how to integrate this interrupter circuit into the device. Because the proximity switch detects ferritic material I created a wheel with thumbtacks placed at fixed intervals around the perimeter. When a thumbtack passes under the proximity switch the switch turns on, when the thumbtack passes the switch turns off.

I added several more layers of wire to the coil, attached it to the new hi-tech interrupter and with a little fussing around, success! A tangible shock was felt when the interrupter was engaged. Knowing the coil was working correctly I built the third and final interrupter for the circuit integrating wooden gears to increase the switching frequency. Everything works like a charm. I will continue tinkering with this device leading up to the Maker Faire to ensure an entertaining and dependable experience.

Buzz-saw Whirligig / Saw-Mill Buzzer

jchismar buzz saw whirligig

Also known as a button-on-a-string, the buzz-saw whirligig is a noise-making device which utilizes an object centered on a loop of cord. The buzzer described in Home-made Toys for Girls and Boys spins a cardboard saw blade to generate its hypnotizing whirring sound. Using both hands the enjoyer must hold each end of the loop and rotate the saw blade to wind the loop. The blade is whirred by adding and releasing tension on the loop which unwinds and, because of the angular momentum of the blade, winds the loop again in the opposite direction.

Making a buzzer is a fun, fast and instantly rewarding project. Cut cardboard, glue a “spool-end” on the center of each side, drill two holes for the cord in the spool-ends, thread the cord through the holes and tie the ends together to create a loop. To my amazement my first buzzer worked splendidly; however Fleur our poodle isn’t as amused by the osculating pitch emanating from the new mysterious gizmo.

I decided build a bunch of buzzers as swag for the Newark Maker Faire. Friends saved cardboard from recycling and donated it to the cause. The cord for the buzzers was retrieved from a pile of bakery string saved from years of bakery boxes. Small bits of recycled broom handle are substituted for spool-ends because I don’t have many spools in inventory.  The title artwork of my exhibit  was printed on the cardboard using a carved linoleum block. To print each buzzer ink was applied to the carved linoleum block using a brayer, the buzzer cardboard was placed over the inked block and pressure was applied to transfer the ink from the block to the cardboard. When the ink dried I cut each buzzer out with a pair of scissors.

Please stop by my exhibit at the Newark Maker Faire, Saturday April 30 to pick up your free buzzer while supplies last!

A Toy Jumping Jack and Eight-blade Windmill

“If at first you don’t succeed, that’s normal” Colbert – Live Free Or Die

jchismar jumping jack whirligig

The Toy Jumping Jack is yet another project I’m building for my Home-Made Toys exhibit for the 2016 Newark Maker Faire. The arms and legs of this toy are pivoted on brads placed through the front and back of the torso. According to the instructions a heavy linen thread is tied at the pivot of each extremity, the opposite ends of the thread are tied to a ring below the torso. Pull the ring downward and “Jack jumps comically” says Mr. Hall, author of the instructions. Why isn’t life that simple?

jchismar wooden jumping jack toyFor me, this project started right as rain. I collected a handful of thin pieces of poplar I saved from various projects and transferred the pattern for the torso, arms and legs. The pivot holes were drilled and the bandsaw was used to cut each part out. The tops of the arms and legs were painted and a strand of thick string was tied to each extremity. Four brads hold the front and back of the torso together and act as pivots for the extremities.

Drum roll please? I pulled the strings down and the arms and legs rotated skyward. Upon slackening the tension, only the legs returned down. The thick string jammed in the narrow shoulder clearance inside the torso. The thin wooden arms didn’t have weight necessary to enable gravity to do its job.

jchismar a toy jumping jack
The tangle of the dangle

The first attempt to resolve the problem was to replace the thick thread with nylon coated stainless steel thread. The new thread was better but the arms were remained too light to function properly. All the original parts were discarded and I found thicker wood to cut new heavier parts. Initially these parts worked well with the steel thread but an unsightly tangle was created when I tried to neatly tie the four lines together.

More attempts to maximize the predictable animation of the jumping jack followed .  The original thread performed best after fiddling around with how it attached to the limb and the location of the knot. Sometimes the task requires a touch more patience and attention than the originally put forth.

Jack’s head was carved from a scrap of basswood; the instructions suggest a wooden spool. This is mostly due to my abundant inventory of basswood scraps and the limited quantity of spools. The completed Jack was installed on the eight-blade windmill I constructed in an earlier post. Jack is so happy to be alive his limbs flail in the blowing wind like the excited customers in 1980’s Toyota commercials.

A Home-made Toy Motor-boat


jchismar.com toy motor boatThe Toy Motor-boat is the first project I completed for my exhibit at the Newark Maker Faire. I wanted to test the boat before I posted and I was slow finding an appropriate time and location to do so. The delay was, in part, because I wasn’t sure it would float let alone propel itself on water. I needed to find a private location with easy accessibility to the water.
jchismar toy motor boat

To build the motor-boat I cut a pine 2 x 4 into the shape of a boat (steps 1 and 2). Using the table saw I trimmed long thin strips from the  2 x 4 and glued them to the sides and back of the boat (step 3). After I painted the inside of the boat (step 4) I realized the stern of the boat was supposed to be angled forward, not straight up and down. I cut off the stern at the appropriate angle and replaced the wood. Step 5 shows the top of the bow being planed from a piece of the 2 x 4. The top of the bow was glued and clamped to the body of the boat in Step 6.  When the glue was dry I sanded everything and completed the exterior painting.

This boat is propelled by rubber bands stretched underneath the boat which are attached to a “tin” propeller. I was certain when the propeller was wound and placed in water the propeller would release all the rubber band energy in one quick burst, much like it does holding it in the air, creating a splash behind a stationary boat. That is if the 2 x 4 boat didn’t capsize before then.

Testing day arrived. Alone, I drove to Branch Brook Park and parked near the Prudential Concert Grove. I grabbed the camera and my motor-boat and sat at the water between Karl Ritter’s lions and anxiously wound the propeller. In my right hand I held the fueled up boat, the camera in my left. Chimes sounded from the Cathedral Basilica of the Sacred Heart as I prepared to be soaked while releasing the boat. At first I thought something was wrong, there was no revving sound or splashing. Then the boat slowly moved away, the propeller turning at a moderate rate.

The propeller rotated almost a minute pushing the boat about fifteen feet against the wind and current. It may have gone further if I paid more attention to releasing slack on the return line. What a surprising outcome! To be sure it really happened I tried a few more times, just as successful as the first. It was time to get ready for work so the testing wrapped up quickly. Otherwise the better part of the day would have been spent sitting by the water playing with the home-made toy.

Clog-dancer Jig Doll Limberjack

“In these days when everybody is talking about doing his thing, here’s the story of a boy that not only talks about it, but does it.”
~My Side of the Mountain movie trailer

jchismar clog dancer jig doll limberjack

I’m learning, as I continue to build A. Neely Hall toys for the Newark Maker Faire, I grossly underestimate the time required to produce each project. Some blame can be placed on keeping true to the 1915 materials and instructions. For instance, the instructions describe the arms and legs as whittled sticks, so the extremities are whittled wood instead of pre-made wooden dowels. The body was cut from a discarded broom-handle found in a storm drain while walking Fleur. The head, hat and shoulders are made from wooden spools; the hands and feet are carved from basswood.

Tacks are inserted at each joint to attach the limbs with heavy linen thread. Tying tiny knots closely together onto mini metal tacks proved more challenging than anticipated. Smaller and more plentiful hands would accomplish the task more quickly. Even the not-so-professional paint job required a surprising amount of patience and time. Does the finished project reflect the work behind its folksy finish?

Tapping the “stage” reproduces a perfect Michael Flatley so, heck yeah the payoff is worth the effort. I can entertain myself for a long spell while simultaneously irritating everyone within earshot of the tapping and clacking. Win. Win.