I posted over at Instructables a project that uses the Parallax PIR Motion Sensor (yes, it IS that same I used in the Halloween Hack, ye of the clan Observant) to encourage me to be working out. If I am, then I am rewarded with some tunes to keep moving along. However, if I am lazy and take a breather…well….. “No Snoop For You!”

The Parts List:

Key objectives here:

Assembled parts used in Motion Feedback MP3 project

If you want more details, head over to the Instructables post.

Here is the project enclosure. Admit it, you love you some Maker’s Notebook, too, don’t you? The MP3 Trigger sits snug as a bug in a rug with the machine screws and nuts anchoring it in place. 2 additional ones hold the PIR Motion Sensor to the front of the tin. Getting the larger hole in the front and back was tricky because I did not have a great pair of snips around. I’ll know for next time! I did manage to wear through several Dremmel bit tips in my stubbornness of using the wrong tool for the job.

New project enclosure idea

Here she be all wired up. Note, she AIN’T wired to the LAN, so this is using the “Onboard Rules” feature. If I did want to datalog the session, I would have to plug in to my router (which in this case really is not more than 10 feet away).

Top View of MP3 Motion Feedback MP3 Player

Acorns from my Oak out front

I am trying to recall the exact moment when I set my mind to making food from acorns. It could have been any of the following moments:

a) When reading “When Technology Fails” I wanted to take a stab at more self-sufficiency
b) When I listened to “Everybody Dance Now” I was inspired by “I’m just a squirrel tryin’ to get a nut”
c) When I moved to into my new house this summer, I saw the MASSIVE oak out front and knew the acorns were coming

Oak tree - the acorn donor

Oak leaf

Whatever planted the seed, it was obvious that I needed to make acorn flour. Apparently, acorn flour was a food that was made by native peoples (I have since confirmed reading some blogs of families of Native American descent who used to hoard massive amounts of acorns for making food).

The first step was harvesting the acorns. At the beginning it was not terribly easy as I stalked the yard (to the bewilderment of my new neighbors who must have thought me out of my mind… or rather, having “gone nuts”) looking for an acorn that had not fallen far from the tree. It became increasingly easy as the season wore on and by the end of fall, I was kicking myself for trying so hard at the beginning of fall where by the end I could, and did, rake bags full of the stuff. Ah well, you live you learn.

Acorns lying in the front yard

Not just for squirrels anymore

After having gathered what I considered a reasonable amount, the next step was removing the acorn top cupule. No, I did not know that word before I looked it up. Feel free to use it in scrabble for 10 points. That was easy enough for the “early season” acorns, and virtually did the job by itself for the late season ones.

Next was going through the stash and finding any acorns that showed evidence of rot, or worms.

Damaged acorn

Telltale sign of worm presence

Next, and certainly the most fun (please note sarcasm) part of the process was shelling. I tried just using my hands, then a few with teeth, and finally settled on a set of adjustable pliers the perfect width to apply enough pressure just to crack the shell when closed. It was a slow and tedious process of cracking and peeling the somtimes stubborn shell from the nutmeat. Many a football Sunday was spent watching a game and shelling acorns. Yeah its weird, but damnit I was determined. When it was all said an done, the shelled acorns gave off a sweet, nutty, almost bourbon scent.

Unshelled, shelled, and acorn shells

So before you just run off and throw a handfull of shelled acorns into your mouth and consider yourself educated, there is something you should know about acorns. Apparently they are very high in tannic acid. This is not good for your system (I have read somewhere that even animals may wait for rains to rinse the tannins). Take a small nibble of an acorn and you will feel that rough acidic bitterness that will turn you off from said handfull. The proces of removing this water-soluble acid from the nutmeat is called leaching. I effectively chopped the acorns into smaller bits to increase the surface area and allowed the water to do its work.

The water browned significantly the first morning, so I changed the water. Then the first night, so I changed the water. Then day 2 morning and night so I changed the water. Then day 3…then day 4… you get the point. 2 water changes for over 2 1/2 weeks. After that time, I tasted the acorn and there was very little residual acidicy, so it was onto the drying phase. I have read its possible to to leach by putting a pillowcase of acorns in stream for a while to do this, or in extreme cases, put them in the upper tank (I repeat, UPPER TANK) of a toilet because the water is clean and changes regularly. I didn’t do this.

Water browned from tannis being leached out

The nutmeat was spread evenly onto a baking pan and I forced my wife to make pizza so I could use the “leftover” heat to dry the acorns. I think they were left in for too long as is evidenced through significany browning. They were almost a coffee roast, but smelled good.

Wet acorn nutmeat before drying

Oven-dried (and roasted) acorns

Ever the purist, I went the motar and pestle route to mill them. (Footnote: This inspired me to read about millstones, which are more fascinating than you think. Take a quick read about the patterns millstones cut with and how they are dressed. I thought they just pulverized, which they do not). After a laborious while, I had made a small bit of flour. Losing steam, I went to my coffee burr grinder and made quick work of the rest, grinding into a fine flour.

Milling the hard way - Mortar and Pestle

After milling the easy, and non-purist, way. Boo technoPhiles!

The last step was to make something edible. The flour tasted fine by itself. Somewhat bland

but with a nice nutty finish. My wife was kind enough to look up a “Traditional Acorn Flour” recipe for Acorn Muffins.

They turned out very dark and after a first taste they were…shall we say….harsh. It didn’t matter and I stubbornly gagged down the muffin, grinning in my self-sufficiency. The recipe did not call for butter nor sugar. I quickly topped them with sugar and ate one with butter. It was much better that way.

Sugar-topped acorn muffin

Nutrition Facts (from http://www.elook.org/nutrition/nuts/3218.html)

Serving Size: (100 grams)

Amount Per Serving

Calories: 501

% Daily Value*

Total Fat 30g 46%

Saturated Fat 4g 19%

Cholesterol 0mg 0%

Sodium 0mg 0%

Total Carboydrates 55g 18%

Dietary Fiber 0g ~

Sugars 0g ~

Protein 7g 14%

Vitamin A 1% Vitamin C 0%

Iron 6% Calcium 4%

So, my technoPhobe friends, this was a fine day. I have never really been a gardener or worked on a farm. I like most Americans get my food from the store. This was about finding a small amount of nutrition raining down in my front yard. It was more time and effort than I was expecting, but its encouraging to think that if I had to, I could survive a couple days by spending a bit of time under an oak. All the better if its mine…

Skull furious you have entered his space

Halloween came out of nowhere this year for me. I have not had the time to do much of anything having just moved into a new house, so I took it upon myself to quickly whip up something to get into the Halloween mood. I was at a local store and saw these little foam skulls for $1.50 and grabbed a couple.  Its fun to see what can be made quickly, and now I have something to put outside when the trick-or-treaters arrive.

The materials:

Parallax Infrared Motion Sensor #555-28027

ioBridge Control Module + Servo Smart Board (or arduino + motor shield, if preferred)

Hobbyist Servo

Resistor

Glue Gun

Mini-breadboard (I used my arduino protoshield from adafruit)

Some wire

2 Red Leds

Sharpie

Foam Skull

1 Sock (yeah, the hood is a black sock)

The object here was to simply make the skull do something when someone approached. I know this is FAR from original, but hey, I was pressed for time (and want to show that simple projects are really accessible to ANYONE) and didn’t want to do much planning. So, the project was born.  I know I am not breaking any new ground here, but it didn’t detract from my bliss at annoying any co-worker who stepped in my office for the last 2 days.  It did make the meetings more fun when the skull open his mouth to speak whenever a colleague would adjust their chair!

Steps:

Foam skull purchased for $1.50.

1- Took a saw to the lower jaw of the foam skull to detach it.

Lower jaw has been sawn off so it can be hinged

2- Bored 2 holes through the eye sockets out the back of the skull to run the LEDs and wires through

Bored 2 eyes into sockets to run LEDs into.

Testing that the LEDs are working and solder joints didn't break when inserting into skull.

3- Attached 2 long wires to the LED leads (drop of solder on each lead)

4- Whipped up a little rig for the servo and skull to sit on

5- Glue gunned lower jaw onto servo rig

Used glue gun to affix lower jaw.

6- Used sharpie to color in jaw (previously white because of styrofoam) and teeth.

7- Ran wires appropriately: (Digital Output -- Eyes, Motion Sensor -- Digital In, Servo Smartboard -Channel 1)

ioBridge wired up.

Parallax Infrared Motion Sensor #555-28027 on a protoshield from adafruit.

8- Set up messaging and triggers on ioBridge (or read digital input and write outputs if using arduino)

Note: I was actually unaware that the messaging and triggers for ioBridge were there, and they are easy to use (basically following the mantra of the platform).  For an arduino, a simple read from the digitalIO and write to a PWM output using the servo library would do the trick, no problem!

Mouth closed.

Mouth opened.

9- Put sock over the skull

Skull with hood (not a gold-toe).

10- Annoy co-workers or greet tricker treaters.

HAPPY HALLOWEEN!

Solar Powered Temperature Sensor

In case you’ve not heard, there is a Green Revolution in progress.  To quote a popular commercial, “The way we use energy now can’t be the way we use it in the future.  It’s not conservation, or wind, or solar.  It’s all of it.”  I have long kept a solar-energy project in the back of my mind, so I ordered a 12v/.2A solar panel power supply from a vendor (note: I erred while filming and said it is a 2A panel.  It is a .2A panel).  As a first step project, I figured I would power up my Arduino, use my shiny new XBee modules, and relay some sort of meaningful data back from this wireless solar-powered microprocessor.

How is the weather outside today?  If I am getting data, its sunny!  And 65 degrees on my deck according to my newly built solar temperature probe.

XBee Communications

I did some first-steps using 2 Arduinos communicating over the default broadcast configurations over a span of about 2 feet.

The Salt and Pepa of the Arduino world.

Arduino 1:  ”Yo.  How you doing?”

Arduino 2:  ”Fine thanks.  Wow, we are talking wirelessly.”

Arduino 1:” These are great days we’re living in, man.”

Arduino 2: “Now, if only I could unhook from this power cable.”

I settled down Arduino 2 after his diatribe likening himself to Pinnochio, and told him that I would take care of it.

Detail of an XBee wireless communication module

XBee Modem off of the adapter board

Serial Communications

After getting the Arduino twins talking (and hey, its all serial!) I grabbed my ioBridge and slapped on the Serial Communications smartboard.  In about 1 minute, I had my ioBridge chatting with my Arduino.  Sweet….  Now, on to untethering my Arduino.  ”I got no wires…to hold me down… la-la-la-la”

The Wireless Temperature Probe

I ran out to Radio Shack and picked up the right barrel plug adapter, and added some wires to run into the Arduino.  Note: the jumper must be set on the Arduino to take power from external.  My Solar Panel provides 12v, and the Arduino can take power up to 12v.

XBee hooked up to temperature sensor

Temperature sensor

I used the temperature probe that I had from my ioBridge, crafted a quick sketch (see below) on the arduino (the analog scaling factor may be off since its not precisely linear, but c’est la vie) and waited for the sun.  As soon as I plugged it in, the Arduino woke up, lights blinking, and was soon processing and wirelessly communicating!  All this achieved because of energy provided by that flaming ball in the sky.  Now that’s cool.

A quick run upstairs onto the ioBridge dashboard and guess what?  The serial monitor widget was telling me what the temperature is outside.  65.31 degrees Farenheight.  Wirelessly and without another power source…

ioBridge and Serial Smartboard hooked up to XBee module

A nice springlike 65 degrees outside at the moment.

Conclusion

Now that I have a solar powered wireless microprocessor at my disposal, I am thinking of giving it some legs, and onboarding some Artifical Intelligence.  Its top priority could be to take over the world.  Take some solace in the fact that the processor is 1KB of RAM, 512 bytes of EEPROM, and runs at a “blazing” 16 MHz.  If that’s not enough, then know that all you need to do to shut down its diabolical scheme is stand over it and block the sun.  Hmm.  Perhaps its better served as  a temperature probe….. for now…

Sketch for Arduino

#include <NewSoftSerial.h>

NewSoftSerial xBeeSerial =  NewSoftSerial(2, 3);

void setup()  {

  // Initialize the on-board LED

  pinMode(13, OUTPUT);

  //Initialize the HW serial port

  Serial.begin(9600);

  Serial.println("Ready to send data:");

  // set the data rate for the SoftwareSerial port

  xBeeSerial.begin(9600);

}

void loop()                     // run over and over again

{

  //Read from the analog input from analog pin 0

  int tempValue = analogRead(0);

  // Send the message to the XBEE Transmitter

  xBeeSerial.print("Time: ");

  xBeeSerial.print(millis());

  xBeeSerial.print(" Value:");

  // Do scaling ~6.875

  float scaledValue = tempValue / 6.875;

  xBeeSerial.print(scaledValue);

  xBeeSerial.print("\n");

 // Update every 2 seconds

 delay(2000);

}

Serv O’Beer has found some interest online through being covered at Instructables, Engadget, Gizmodo, Make, and others.  Of particular interest is its inclusion in the How 2.0 section of Popular Science April 2009 edition, and PopSci Online.  Yeah, the 100,000 YouTube views are eyebrow-raising as well.   We really appreciate all of the comments and suggestions, and those who laughed along with us at the “usefulness” of a machine that can pour us a REAL beer using an iPhone.    

Serv O'Beer in Popular Science

You can see that the v 2.0 Serv O’Beer has been plated for ridigity, and some additional braces added to provide for a more smooth pour.  Also a high torque servo has been added to allow it to serve as a brake, rather than just a pushing arm, and then a brake (hence the high volume of head in the beer).  

Again, thanks to everyone who has laughed, sat confused, rolled your eyes, or said “Dude, that is sweet.  You need a better outlet for your spare time”.  Mostly, the latter.  Just a closing note: The servo and the ioBridge do the work, I just get to use my Construx for something again, and drink 3-4 beers trying to calibrate this sucker.  Sounds like a win-win to me.  

Check out the article in the April Issue of Popular Science.

PopSci April 2009 Issue

Thanks again, everyone.   I’ll pour one for you!

Tabletop Trebuchet

The trebuchet was a siege weapon with an interesting and complex history.  Where some weapons employed torsion of ropes or sinews (such as the ballista, catapult, onager, espringal, etc) the trebuchet was a great advance as it used a massive counterweight to store the potential energy.  Nowadays, these machines are used to throw pumpkins, cars, or just about anything.  They are also the objects of much analysis for people trying to understand physics.  This is an interesting and efficient throwing machine, so I had to build one.  It has even recently been featured on Make.

While there are many kits out there and “right ways to build” a trebuchet, I wanted to simply go on illustrations from a book I had received for Christmas.  Reverse Engineering, old school.

Armed with the tools of the trade, a book on the subject, and some time,it was time for a build.

Here is the workspace in my basement.  The trebuchet was to be built from scratch using balsa, basswood, and some dowel rods.

Built base. Notched 6 positions for frames using X-Acto knife. Also note lateral stabilizing arms.

Counterweights- fishing sinkers

Building the Basket

This was one of the more “complex” parts of the build.  The basket had specific shape requirements to keep the basket from flipping over, and had to hold a good amound of weight relative to the build material (balsa).  Lastly, it could not dump the lead weight as it accelerated downwards.

Basket parts and throwing arm pre-assembly

The two basket sides and the basswood throwing arm.  Also 4 dowel rods are used to give additional support under the lead sinkers used as counterweight mass.

Built basket and arm.

Almost fully built basket.  Need to add planking to the base so the lead won’t fall out.  Also need some washers on the sides of the arm to minimize friction loss.  The dowel pegs do add quite a bit of strength and stability.

Building the Frame

This was very derivative off what I saw the in my Ancient and Medeival Siege Weapons book.  Its a rather simple A frame with some additional supports, but I added 2 basswood squares to stabilize the frame and give the throwing arm axle something firm to rotate through.

Build stand and throwing track.

The built up frame.  Also note the flat track for the sling and projectile to slide with minimal friction as it accelerates.  Here you can see the angled braces keeping the frame up (that were coming out of the sides of the base).

Sling release. This is a small dowel peg at the end of the throwing arm where one end of the sling is tied, and the other is looped over the peg to slide off at the proper point.

Detail of the sling.  I screwed a small brass eyelet here to tie one end of the sling string to.  The other has a simple tied loop, and is able to slide off as the sling angles around the throwing arm.

Illustration of the frame, and the book image used as the subject of some reverse engineering.

Take a look at the illustration.  See any similarities?  Ah, yes.  The hamster wheels are missing.  Those were used for men to wheel the heavy arm back down, and the counterweight back up.  Real hamsters would be appropriate at this scale.

Ready, Aim, Fire

Trebuchet in resting (vertical) position. The counterweight is directly below the throwing arm at its lowest energy.

Trebuchet in loaded position. I am holding the sling with my left hand.

Conclusion

I really don’t know when I became interested in this neat little machine.  I had stumbled upon The Grey Company’s Site, and their trials to build this class of tabletop trebs called “Cheese Chuckers”.  There are sophisticated software packages that will allow you to run simulations to optimize your machine.  Whether you want to build one to throw a car, or as I did, one to roll a die in a room at least 30 feet long, you can rest assured that your home is safer with one of these siege engines standing guard.

Indoor Airsoft Shooting Range

A friend of mine who is something of an avid shooter had mentioned the lack of affordable “action” type targets.  After some discussion, we determined it would be fun to build such a contraption for some indoor airsoft practice.  The Arduino Diecimilia was a great choice for the “programming side” of things (I have 2 of them, he has one as well).  

As a shooter, you would want to be up-range from the targets, so having something portable with a web interface was a great solution so nobody would have to be “in the line of fire”.  The iPod Touch and the ioBridge module I used in another recent project.  Of course, why build a custom target enclosure when I could snap one together with my Construx.  

Victory! Let the fun start!

I used 3 of my hobby servos to turn the target faces. I am tightening the Construx frame to the hobby servo mount.

Building the target faces

Arduino Pin-Outs:

• Pin 13 -- Debug LED
• Pin 12- Ready for Command
• Pin 11 -- PWM for Servo 1
• Pin 10 -- PWM for Servo 2
• Pin 9- PWM for Servo 3
• Pin 8- Incoming Command Pin (PWM from IOBridge)
• Pin 7- Command Waiting from IOBridge
• Pin 2- Peizo Speaker Control

Not to mention the ioBridge wiring, and the Servo wiring. Yeah I have a diagram or I would STILL be working on it. 

A rats nest of wires for the first pass

 

Debugging the system

It looks a monstrosity, but once the target face is on it, I cut up some cloth as the Airsoft BB trap, it will look just fine. 

All done, ready to rock!

System debugged, targets turning!  Now I can call out the programs remotely using the web browser in the iTouch and let the IOBrige tell the Arduino to do my bidding.

How the Airsoft Target Range Was Built

Arduino Source Code: Arduino-ioBridge-Airsoft-Source-Code.txt

I would say this was a fun, interesting, and rewarding project.  I have also made it future-proof enough to scale up the number of targets for even more options.  For those of you airsofters who don’t want your skills to dull over the winter, turn your basement into a range!  

Now, should I put hay-bales on a servo platform for an indoor archery range?

Happy tinkering!

Full Video Version (Combined Demo + Instructions)

With New Years fast approaching, I wanted to make a project that allows for the perfect pour and take out all of that physical work. Using Construx as the mechanical platform, a servo driving the action, and ioBridge controlling the system, I was to achieve “the perfect pour” controlled with the turning of my iPhone (using the accelerometer feedback determing the screen orientation). We’ve all seen the iBeer application on the iPhone, and now I can actually enjoy the IPA rather than just virtually pouring!

UPDATE:

The information about this project can be found at Instructables.com including steps to make it. Also, you will see the project was picked up at Gizmodo, Engadget, ioBridge Projects, and the fine folks over at MAKE.

Why Weave?

So you may rightly be asking yourself “What in this dude’s right mind does he want to have to do with weaving? Doesn’t he have anything better to do?”. A fair question. However, let me take a moment to defend myself. Really the catalyst of all this, and a lot of the technoPhobe content, stems from a random meeting at a bar. I had just finished the longbow project, and was in Wolfboro Tavern in New Hampshire enjoying some drinks with my stepfather. Somehow we got to talking to a guy next to us who was ravenously attacking a plate of wings like he had never eaten before.

“Wifes a vegeterian. She’s out of town, so this is one of the few shots I get unless I am teaching class.” , he says.

Inquisitively I ask “Class?” What do you teach?”

“Primitive survival skills.”, he adds as another defleshed wing bone hits the plate.

Needless to say, I had many other questions for him. We talked about longbows, firebuilding, etc. Before he rolled out for the night, he turned me onto this book “Caveman Chemistry” (author Kevin M. Dunn. A great book I may add now from experience. I have bought 4 copies for friends). There is a chapter on spinning yarn, and hence my desire to be able to spin, and weave, something of purpose. Spinning I will cover later.

The Loom

The first step is to buy (or build from Construx) a loom. Next, you have to “warp the loom”. This is done by running yarn lengthwise on the loom. By alternating direction in a figure 8 type fashion, you can create what is called a “natural shed” against the loom. No need to bore you with details.

Loom built of Construx

As mentioned, warping yarns are the long yarns that run the length of the loom (in our case, this could change depending on the loom). The weft yarns to back and forth.

There are all kinds of interesting patterns that you can make by changing the pattern of which warp yarns you go over and under. Alternating each (over, under, over, under) is called a “linen weave”. (Here in this illustration, + is over the warp, -is under.

+ – + – + – + – + – + – + – + – + – + – + – +

- + – + – + – + – + – + – + – + – + – + – + -

Another example is the twill weave (under, over, over, under, over, over). Note the diagonal bands taking shape in the twill.

- – + – - + – - + – - + – - + – - + – - + – - +

+ – - + – - + – - + – - + – - + – -+ – - + – - +

- – + – - + – - + – - + – - + – - + – - + – - + -

Here the shed stick is opening the "natural shed"

As a kid, you may have had a loom and used a needle or shuttle to go over and under the warp yarns. Well, obviously a better system existed. Using a device, you can mechanically raise the odd and even warp yarns, and just shoot the shuttle down the gap (known as the shed). The one raising the “natural shed” (the yarns naturally raised by the loom) is called the “shed stick”.

Here the "heddling stick" raises the alternate warp yarns opposite the natural shed.

The implement that raises the alternative warp yarns is called the “heddling stick”. There are also looms (one of which I will no doubt build as I have acquired the wood for it) which achieve the heddling action as a function of the loom itself. This is called a “rigid heddle loom”.

Using a fork in a whipping movement to compress the weft yarn

So by simply alternating raising the natural shed, running the shuttle down, raising the heddling stick, bringing the shuttle back (rinse and repeat), you achieve this linen weave. Each couple of rows we would use a fork to tighten the weave.

Here are some additional shots showing cleverness from my technoPhobe cohort in finishing the seam with a needle, working the leather base, and finishing the product.

Detail of the opened shed

Almost 50%

Finally done. This needs to be automated.

Sewing the seam

Borrowing the innovation of a needle

Finished at last

Note the leather guard at the opening to prevent damage, and the leather base that my friend made very successfully.

Now, all I need are some arrows, and I can live off the land. Provided the land has an XBox 360, and a power supply.

Longbow on tillering stick

The Short of Longbow Building

There are many factors that affect the efficiency of the longbow. All things being equal, a heavier draw weight (the strength needed to pull the bow back to full draw length) yeilds a faster arrow. However, if the bow does not effectively transfer that energy quickly and effctively into the arrow, a lower draw weight bow will outshoot a heavier one.

• Draw Weight – as noted above – the heavier, the faster the arrow
• Draw Length- The longer the bow, the faster the arrow.
• String Height- This one may feel counter-intuitive, but a lower strung bow makes for a faster arrow.

There are many other factors regarding where the mass of the limbs is located, internal friction in the limbs, arrow mass, etc. If you are interested in all of those details, I leave it to the masters in “The Traditional Bowyer’s Bible” (yes, there are 4 volumes). Its easy to follow, and you’ll be amazed how complex this little machine is. Also, its amazing how the ancient cultures “happened” upon massive improvements such as the recurve, composite bow, and others. Neat stuff, but I digress.

Starting to Build

There is much to know about what to look for in the wood you use. It’s an artform in and of itself. Osage Orange and Yew woods are great traditional ones to use. For us, we used ash. To keep it simple here, the tree lays down a new ring each year (yeah, remember looking at cross sections and counting rings as a kid, right?). Ideally you want the “back” of the bow, which is the side facing away from the archer, to be one continuous growth ring. The back of the bow is under significant tension (where the “belly”, or side facing the archer, is in compression) so a single ring affords by far the best tensile strength. In this picture, we have cut the wood (called “the stave”) at an angle aligning with the growth rings to give us good strength.

Note the light and dark bands

Natural Born Tiller

We have created our profile of the bow, and marked off the taper to an appopriate notch size. Warm up the rasps and planes, because the hard work is about to begin.

Here we mark off the taper to the notches to be planed off.

This is where the real work begins. This is the process of “tillering” the bow. Once you have done what you can to get the back of the bow to a single growth ring (ours was not perfect, but good enough we hoped) the long process of reducing the belly begins. Using a rasp and plane (many bowyers are adept with a drawknife) we reduce the wood to it starts to bend, and place it on a “tillering stick”. This holds the bow in place and has inch by inch notches to draw the bow longer and longer back.

Here with the rasp, plane, and drawknife is the real work.

Longbow on tillering stick

As we plane and put the bow on the tillering stick, we are looking for places where the bow bends unevenly. That indicates there is too much wood on a limb of the bow, and needs to be balanced. Here is an example of a “hinge” that has developed due to uneven tiller.

Note the hinge that has developed on the bow. More work needed here.

Here the hinge has been tillered out of the bow.

Also you can get a sense of how the tiller is going doing by drawing the bow yourself. This bow was damn heavy at this point.

Testing the draw weight of the bow.

Finishing and Testing

After 8 hours of tillering (I don’t know what the average is, but I doubt it should have taken that long), we used a bathroom scale to test the draw weight at a given draw length. For us, we ended up with 45 pounds at 28 inches draw. Not a heavy bow (some of old English warbows were 100 pounds plus. Forget that image of little wussy archers in tights), but still seemed functional for a first attempt.

Testing the weight on the scale

Successfully firing the bow