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Turn the handle on the side of the Flexibot and the scotch yoke mechanism operates the flex arms. The file for the model parts are available for members to download for free, thanks for signing up! Non-members can join in the fun for £2.50.

The file comes in both coloured and non-coloured version. Print out the parts of your choice onto thin card (230 gsm) The straps that are used to pull the arms need to be printed out onto ordinary printer paper (80gsm)

Score along all the dotted and dashed line and cut out the holes before carefully cutting out all the parts. Follow the instructions below to put together the Flexibot.

Start by gluing together the yoke. Glue the two slider tubes into place, one at each end of the yoke.

Roll round and glue together the five paper tubes lining up the edge as accurately as possible with the points of the arrows.

Assemble the two crank pieces.

Assemble the handle in three steps as shown.

Thread the longest of the five tube through the yoke then assemble the crank parts in situ. The other two tubes are the ones with triangle arrows rather than squares. The crank should be free to move inside the yoke.

Fold up and glue down the tabs on the base of the box parts to make right angle triangle tube sections.

Glue the two parts of the box together.

Slide the two pillars into the slider tubes as shown.

Fit one end of the crank through the hole in the box side.

Fold the box round threading the other end of the crank into the other circular hole.

Glue the box closed.

Glue the two pillars in place using the faint grey arrows for alignment.

Glue the box top stiffener tube to the underside of the box top as shown.

Glue the box top into place on top of the box.

Flip the box over and glue down the two tabs.

Glue the four vertical tabs to the insides walls of the box.

Complete the box by gluing the handle into place.

Once the glue is dry, turn the handle to make sure that the scotch yoke is working properly. The yoke should move smoothly up and down as the handle is turned.

Roll round and glue together the two leg tubes joining then in the middle.

Glue the leg end cap into place.

Glue the six tabs to the inside ends of the legs.

Before you start gluing the arms together fold along all the crease lines to ensure that they flex freely.

Assemble both arms by rolling round each half section and gluing it down. Use the lines and arrows for alignment.

Work your way to the end of the arm.

Thread the long paper strips through the arm and glue the end to the inside top of the narrowest section.

Let the glue dry then try pulling the paper strip, the arm should flex upwards.

Make up the claws from double thickness card.

Fit the claw into the end of the arm.

Glue together the arm holder and thread the two remaining paper tubes into place.

Glue together the two parts of the body and roll them round fitting the arm holder into place with the hole facing downwards as shown.

Glue the body closed.

Assemble the head and fit it into the body top.

Glue the body top into place and glue the eyes onto the head.

Slide the arms into the arm holder carefully threading the paper strips down through the hole and out of the bottom of the body.

Thread on paper strip one through each leg and glue the legs into place in the body.

Thread the paper strips down through the top of the box and glue the legs to the box top.

Turn the handle so that the yoke is at its lowest position.

Pull the paper strip so that the arm is up as high as possible and glue the end of the paper strip to the side of the yoke. Repeat this process with the other paper strip on the other side of the yoke. Let the glue dry.

And there it is complete! Turn the handle and marvel as the robot flexes his arms!

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Mon 21st Apr 2014

All the parts for the Flexibot cut out and ready for final testing.

Everything fits together nicely and the end result runs smooth as silk.

Next step, colour.


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Experience has shown that connecting acrylic gears to acrylic shafts is tricky. Up until now I've been cutting holes in the acrylic with the laser cutter and push fitting the gear onto the shaft. For a 6mm shaft I've cut a hole between 5.7mm and 5.8mm. Sometimes it works, and is a nice tight fit, other times the gear cracks as it is pushed into place.

My first attempt as designing a sprung connector failed when three of the five fingers snapped off at the first attempt.

My second design is simpler and hopefully more robust. I've added curves to all the corners to spread the strain.


Here are the first and second drafts for the gear centre design. in each, the central circle is 5.7mm in diameter. The spring of the three fingers allows a 6mm shaft to ft into place and grips it tightly.

Here are the final gears cut out and ready to go.

They work nicely, gripping the shaft and holding the gear square.

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I'm in the final stages of designing the Flexibot model. As the handle on the side of the box is turned the arms lift up and down lifted by pulling on a paper belt. The box that the robot is standing on is based on the scotch yoke mechanism.

I've removed the central shaft from the original scotch yoke design as it is not needed. As the crank turns the yoke is lifted up and down.

The paper belts that drive the arms are glued to the yoke. As the yoke moves down, the arms are pulled up. When the yoke returns to the top of its range the arms drop down again through gravity.


Looking good!

There are a couple of changes I need to make before the model is complete including moving the robot further back on the box. It should be a cute little model when its done!

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Thu 17th Apr 2014

The nice driver from UPS dropped me off a parcel this morning. It contained my author's copies of the second edition of Gizmos. I'm delighted, it looks great!

The from of the box features a picture of the Marching Robot, the back shows the other five models that are in pack ready for you to make. Die Fledermaus, Surfing Bunny, Mouthy Moose, Schrödinger's Cat and the Shrimp Boat.

Inside is a wire-bound booklet with all the parts and instructions.

Each model has an introductory page...

...and full instructions for construction.

Best of all, as well as the parts sheets in the book which are ready for you to cut out and make, there is a separate pack with a second full set of parts sheets pre-cut and creased, ready to pop out and make!

Gizmos is available to buy from Barnes and Noble shops. You can find out more details here.

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Tue 15th Apr 2014

Here's an interesting mashup. Our friend Mr Cool has used the interchangeable cam from the T.Rex mixed it with Guard dog dog to create this delightful model. Nice one!

Meanwhile Michael42er has produced this elegant modification to the recent Owl model. A simple cam on the vertical shaft flaps the owl turns his head. Fantastic work Michael!

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Mon 14th Apr 2014

Reading though some back posts I came across the flexbot project that I had worked on some time ago. That project project eventually morphed into the flexiphant and scotch yoke mechanisms but it seems a shame to see the original idea go to waste. To that end I've dug out the files and am now working on a completed version.

The original stop-motion animation shows how the arms will work. Paper straps connected to the insides of the wrist and running through the length of the arm are pulled down lifting the arms as they do so.

In the original mechanism I used a pair of bell cranks to change the direcion of pull.

In the new version I have run the paper straps over a
couple of paper pins as shown below. Far simpler to make.


I'm changing the design of the arm in the next draft. In the current version the segments that make up the arm are all equally spaced. This in turn means that the angle of turn in each section is the same. I would prefer the parts nearer the body to flex less than the extremities. To that end, I'll be closing up the gaps between the segments. The closer to the body, the smaller the gap.

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In this blog post I'll explain how I linked together two paper projects to make an Animated Paper Owl. Start with the two projects, Owl Papertoy and RRVSt2. There a couple of small pieces that you will need to make to join both parts together.

Members can download a template of the parts at the link at the top of the page. If you prefer you can make up the parts using these dimensions. Make them from thin card.

Assemble the Owl and mechanism box following the instruction on their pages. For this simple model the wings are not animated so there is no need to connect the long wing pulling tabs.

Glue a small off-cut to the back of the owl as a tab.

Glue the tab and the feet to the box so that the vertical shaft is centred within the body.

Glue together the two Owl Link parts as shown.

Glue the Owl Link to the inside of the owl's head.

Fit the square tube of the Owl Link over the circular shaft of the box. Don't use glue, a friction fit allows you to make adjustments to position and orientation.

Turn the handle and be amazed just how far the owl can twist his head!

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Add to Cart to download this kit for free !
Download Owl Papertoy

A simple but fun papertoy owl to download and make. This model can be used as a static model or with a little ingenuity, as part of a paper animation.

Everybody can download the parts for free. Have fun!

Print out the parts onto thin card. Score along the dotted lines and cut out the holes before carefully cutting out the parts.

The head is made by rolling round the head strip and gluing it down then folding down the curved flaps. No need to glue them.

If you want to make the wings move, glue the top of the strip to the back of the wing so that it just touches the crease line at the top of the wing.

Glue the fillet into place to make a bell crank as shown.

Thread the long tab through the hole in the body and glue the semi-circular tab to the grey semi-circular area. Repeat this process with the second wing.

Roll the body round and glue it down.

Glue on the feet.

Glue the head to the body to complete the owl.

Use this as a finished model or as a starting point to design your own paper animation model. I'll be demoing an idea or two in the next few posts.

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Sun 6th Apr 2014

Two YouTube videos for your delight!

Firstly. Cool022883 has produced this delightful "Cow Jumped over the Moon" model using a combination of crank slider, leaping goat and what looks like the head from the Rumination model. Nice work!

Secondly Michael42er has modified the latest RRVS mechanism and used it to charm this paper snake. Thanks both of you, I always look forward to seeing what you will do next!

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