Carving And Animating a Tail-Wagging Dog

Introduction

Animation has always been a passion of mine. When I learned to carve, bringing the two together became somewhat of an obsession. I visited the Paul Boyer museum in Belleville, Kansas a few years ago and was so impressed with his animation that I made a website to show his work on my own site. You can find Paul’s and my animations at, http://www.LivingArtInWood.com.

Because of the website, I began receiving requests for information on how to get started in animating woodcarvings. Most of projects I had done to that point were a complex system of gears and cams and many hours of trial and error (sometimes many many hours.

As I pondered this request I more or less stumbled on a very simple mechanism to wag the tail of a dog in a seated or lying down position. While the mechanism is simple, there are some electronics involved that will require some soldering on a circuit board, The tail is “wagged” by a magnet pendulum that swings over a coil triggering a transistor that gives a short burst of energy to the cid giving the magnet a slight “push” keeping it swinging as long as the batteries last which can be several weeks if left running continuously. Solar cells can also be used that will keep the tail wagging as long as they are in sufficient light.

This article is the fulfillment of that request. There will be a parts list for those who want to find their own. However, because postage often costs more than the part needed, I will offer a kit of all required parts and an option to assemble the circuit board if desired. So with that introduction, let’s carve a dog that wags his tail.

Carving the dog

You can carve any dog you have a pattern for as

long as it’s in a sitting or lying position. Since the focus

of this article is on animation, instructions are limited to

the modification carving instructions are not given.

When you carve your dog, make the body and tail

separate.

Figure 1 is a sketch of the basic tail wagging

mechanism. As the magnet pendulum swings over a

coil, it is given a slight nudge it passes over. The tail

wags with the swinging of the pendulum. This type of

mechanism can be used for any dog or other animal that

is carved in a seated position. The reason for the seated position is that in a standing dog the tail appears to wag from side to side while this mechanism “rotates the tail. The entire mechanism is assembled separately from the control circuit and has no contact with it other than magnetically.

Figure 2 shows a carved tail, the rod and rod. Lay out the style of tail you want and carve that when you’re carving the dog. Make sure the grain of the tail runs with the length of the tail in order the give it as much strength as possible. If the grain runs crosswise, it’s fairly easy to break one off.

Once the dog is carved, make a groove on the bottom where the brass rod to be glued as shown in figure 3. The groove should be just deep enough for the entire diameter of the

rod to fit into.

The rod and sleeve parts are included with the kit if you

purchased one. They are also available to most hobby and some

hardware stores. The rod shown in the Figure 4 is a 1/16 in.

diameter rod and fits perfectly into the sleeve for a bushing-like

fit. Prepare the sleeve by cutting it to ½ to ¾ of an inch. Make

sure the groove is long enough for the sleeve to fit into without

sticking out the back where the tail will be attached.

Before bending the rod, buff it to a shine with fine steel wool so it

will easily turn inside the sleeve. Check to make sure there is no binding. When bending the rod, use care not to score the surface where the rod will remain in the sleeve.

Bend to make the pendulum. Make a 90o bend far enough from away from the end of the rod so that about ¼ in. sticks out past the sleeve when it is in place so you can attach the tail. Figure 4shows the bent rod and the sleeve on the end. Note the small washer that is glued to the rod at the bend to keep the sleeve from binding on the rod when swinging. The washer is a plastic bead that is drilled to fit the brass rod.

The length of the rod to which the magnet will be attached determines the speed that the tail will wag. In the prototype shown, the rod was 2 ¼ inches from the bend to the end of the rod where the magnet is attached. That appeared to give a fairly realistic wag effect.

Before installing the sleeve and rod into

the slot, attach the tail to the brass rod. First

carefully flatten or rough up the tip of the rod just

a bit to give the epoxy something to grip to so the

tail won’t twist on the rod.

Drill or grind a hole (Figure 5) into the base of

the tail where the rod will be secured. Using

epoxy, glue the rod into the hole in the base of

the tail.

There are two concerns while doing this.

First, keep the tail in line with the rod to which

the magnet will be attacked unless you don’t

mind the tail resting at a tilt when the magnet isn’t swinging. Second, be especially careful not to get epoxy on the rod or it won’t swing. Figure 6 shows the tail glued to the rod.

If you haven’t yet done so, put the washer on

the rod. Since it is narrow, it will make the bend and

can be put on from the magnet end. Line it up

square with the shaft and glue it in place with epoxy

on the end away from the shaft.

Now you can begin preparing to glue the rod into

the groove you carved out earlier. I found it is best

to “tack” the rod into place first, either with 5-minute

epoxy or hot melt glue. Use just enough glue to

hold it in place until it sets. As shown in Figure 7,

you can hold the rod in place with a couple of

clamps. One it’s set, you can test to see if it swings freely when it is dry. If it doesn’t you can still take it out and free it up. If it swings freely, put more epoxy, or whatever glue you’re using, around the rod to hold it in place. Once again, be especially careful not to get any glue near the places where the rod sticks out of the shaft. It takes very little glue on your finger to cause sticking. If it does stick slightly, a small amount of WD40 will loosen it up if the glue is just on the surface.

The magnet is connected to a dowel that is drilled and attached to the rod that swings down. If you’ve cut the rod to the size you want, slide the dowel on to the rod and glue it with a small amount of epoxy or crazy glue. You may want to attach the magnet at this point. Don’t put in permanently yet. Put it on with tape or something that will allow you to remove it later. You’ll need to have it loose later to determine4444

The rod should now swing freely as it hangs down from the dog and the tail should wag with each swing. Now you can mount it on the platform that will be the base for your carving. You will need to cut a hole where the rod can go through and the dog will be attached. I’d recommend a platform that’s fairly thin so you won’t need to cut so much from the bottom in order to let the rod to swing from side to side. You may also need to take some wood off the bottom of the tail if it rubs against the platform. If it drags at all, it won’t swing.

Figure 8 shows the pendulum rod, dowel and magnet from the bottom of the platform.

Mount the dog in place with small screws. Then cut four legs to support the top platform approximately 2 ½ in. long or as high as you want he bottom “box” to be. The actual length of the wood pieces depends on how high you choose your bottom base to be. Then cut four shorter egs that will support the lower platform on

which the electronic circuit board will sit. Cut

them so that the bottom platform will be about ½ in. below the magnet bottom when it hangs down as shown Fgure 9. Glue the legs to the top base with one long and one shorter leg together. Turn them so the shorter legs are visible when looking at the dog from the back or the front, as shown in Figure 9. The lower platform will be

mounted tothe shorter of the

two legs. Cut the lower platform

so that it fits between the shorter

legs but extends to the edge of

the longer egs. You will then be

able to mount this platform by

screwing it to the shorter legs.

Put the lower platform in

place and mark one leg and also

a matching spot on the platform so it can be put in the same way in case you remove it for something.

You should now have a completed tail-wagging dog. The pendulum should swing freely. Next comes the fun part, bringing it to life. Those instructions are on the link for the assembly of the electronic circuit.

Parts List

1.A 1/16 in. brass rod (available at hobby shops (particularly at radio control airplane shops and some hardware stores.

2.A brass sleeve with the same inside diameter as the rod. (You only need less than an inch of the sleeve.

3.A ½ in. rare earth magnet. (Available from http://www.leevalley.com.)

4.A ½ in. piece of ½ in. wood dowel for the magnet mount.

5.A small (approximately ¼ in.) plastic washer (bead)