Owl Clock

Hey everybody.  This is my first real instructable.  I'm entering it on the Make it Real Challenge so if you like it, vote vote vote!  All of the machines used in this Instructable should only be used with proper training, knowledgable supervision, and extreme caution.  Know what you're doing.  I'm not responsible for anything you do to yourself while completing this Instructable.

I am a high school student, and for my Computer Integrated Manufacturing class (CIM), our project for this month is making a clock.  We have to design and build a clock of our own design that fits a pre-made clockwork.  The main body of the clock has to fit on an 8"x8"x.5" (rough) piece of aluminum, and we can use the plasma cutter as well as the mill. This Instructable is designed to be a rough guide not only on how to make a clock, but on how to set up and use several machines as well as showing several design and shop techniques to help you along the way.  Hope you enjoy!!! I know I did!!!

Materials
8"x8"x.5" piece of aluminum stock
Sheet of .125 plate steel for use on a plasma cutter
Clockwork
Inventor student (or whatever CAD program you prefer)

Tools
3-Axis CNC Mill with a .5" end mill, a .25" end mill, and a .1" end mill
Plasma laser cutter
Calipers
Sandblaster (Optional)

I'm using Inventor to design my clock.  You can pretty much use any design software that is available, but I learned how to use Inventor through my high school. Start by making a new project in your program.  Take your clockwork and dimension it and make it into a part on your computer.  You do not need all of the minor details, but just make sure you have all of the major details that will determine how it will fit in the shell of the clock. 

The stock I am using will be 8"x8"x.5".  Start by making a square 8"x8" and then extrude it .5"

Next, create a sketch on the front plane of the stock.  This is where your design for the clock face will go.  For the Owl, I will be using an oval shape for the body with triangles for the ears.  Make sure to get the body centered.  For symmetry, start by rough sketching an ear on one side, and then mirror it to the other.  For the mirroring line, I made a construction line going down the center of the stock.  Make sure to trim the insides of the ears to make the extrusion less finicky.  Make sure you either extrude back .5" or select extrude all.  Remember, you're extruding around the body, not the body itself.

This clock will look like a perched owl, so the wings will be slightly folded back, not full spread.  But feel free to do whatever you like.  After all, it is your clock.  Start out by drawing an arc from the middle of the body going down on the outside of your body.  The center of the arc should be outside of the stock somewhere.  This should be the top edge, defining how large the wing should be. Next, use another arc to complete the bottom.  Once you are happy with the shape of your wing, mirror it to the other side.  Make another construction line down the middle and mirror the wing across.  The main body of your owl has been designined.

Create two circles that will be the eyes.  Make sure that they overlap in the center.  The eyes will be gears that can rotate.  Instead of cutting them on the mill, we will cut them on the plasma cutter.  I made the outer circles for the eyes 2.25" in diameter.  I dimensioned the left eye 3" away from the left edge of the stock and 2.5" from the top edge of the stock.  Mirror the eye across the center.   Now make a smaller circle on the inside of each eye.  Be sure that the inside circle does not touch the edge of the opposite outer circle.  This will be the base circle for the gear.  We will make a separate drawing file for the eyes, but you need to see how big they eyes will be to determine the features of the body.  Make a new drawing file for the eyes.  Copy all of the drawing file aspects of the circles on the body onto the new drawing file.  Next make a line facing out of the inner circle reaching to the outer circle, as the left side of the gear.  Mirror this across, now you have one tooth of your gear.  Copy and revolve this around the circle so that there will be teeth around the gear.  I made 10 teeth on my gear because that will allow space between the teeth of the gear for the opposite gear teeth.  The eyes will be cut out on the plasma cutter like gears so that they will spin when you move them with your hand.  BE SURE THAT THEY OVERLAP IF YOU WANT THE EYES TO SPIN!!!  We will be using a 1/4-20 bolt to attach the eyes to the body, so make the holes in the gear slightly larger than .25".  Mine are .275.  For the holes in the body, make them .20". They are smaller than .25" because that is the size of a 1/4-20 hole pre-tapped.  We will be tapping these holes for the bolts that hold the eyes onto the body.

Create a new assembly file and import the owl clock body to it.  Import both gears and place the center of the hole of the gear onto the center of the hole on the body.  Do this both times.  This is more of a proof-of-concept to see how the gears will fit.  Mine are a bit loose, but they're only for decoration.  You now have your eyes and your body done.  We're going to finish the drawing files before we machine anything, so sit tight and stay at your computer! 

Now we're going to work on the details of the body.  These will be simple pockets and contours on the face of the owl.  We're going to start out by making the wings look partially separated from the body.  Just make another arc inside off of the wing so there is a gap between the body and the wing. Offset the arc into the wing so that you have two arcs with a .125" space between them because the smallest tool that will be used on the mill will be a .1" tool. There should always be a tolerance from the tool and the material.  Extrude the gap between the spaces so that it cuts into the material .25"

Start by takinig a line halfway across the main body oval.  Make a regular triangle and move it close to the edge so that a face is on the line that you drew.  Pattern this triangle so that it is evenly spaced across the bird.  My triangles are spaced 1.75" and there are three of them. Make another detail on the body for the bottom layer of the details.  Use the same process for this.  I only have two triangles on the bottom row.  Once you have your design as desired, extrude AROUND the triangles so that it looks like they are sticking out.

Start a sketch on the left wing for those details.  Start by drawing an arc above the base arc of the wing.  Offset this arc three times, so you have four arcs inside of the wing.  The gap between the base arc and the first arc can be whatever you want, but the next distance needs to be .125", because we are using a .1" tool as our smallest.  We are going to have two gaps like this, so space the next arc however you want, but place the last one .125" away from the third arc. The offsets will not be perfect and connect to the edge, so just use a line to close the gap from arc to edge.Once you have all of the arcs placed how you like, mirror all of them across to the other wing.  You are now done with the body detail.  You can still do whatever you want, but I'm going to move on.

Open up your assembly and update all of the parts.  You should have the gears on your newly detailed body.  Nice, right?  Pretty sweet clock.  The rest of our drawing will be on the assembly because we need to see how all of the parts will fit together.

Import the clockwork into your design.  We will be sketching from the back for a while.  My clockwork's main stem is .49", so I'm making my hole for it .5".  Insert your clockwork stem into the hole and start a new sketch on the back of the owl.  It doesn't need to go all the way in, because we're making a pocket for it to fit in the back of the owl.  Project the shape of the outside of the clockwork to the back of the owl.  Offset the sketch so that it will be big enough for the clockwork to fit through, but small enough so that it doesn't get too close to any other features of the owl.  Make the hole for the clockwork deep enough so that the clockwork fits inside, but shallow enough so that it doesn't cross through to the front.  I made my hole .2" deep.  Delete the clockwork from your assembly so you can
re-constrain it into the hole.  Make sure that the hands will be above the gears and that there will be no interference.  If you want, you can make little marks so you can see what time it is.  I'm putting rectangles at 12, 3, 6, and 9 o'clock.  A simple extrude of rectangles at these positions will accomplish the effect.  Before you go onto the next step, make a drawing of the rough stock behind the main clock body.  You are now done designing your clock! =D

You can't just import your design on your machine and expect it to know the stock size and what tools too use for cutting your part!  Start by importing your part onto your tool path software.  Tool paths are the directions that specify which tool is cutting where.  I am using MasterCAM 5 to determine my tool paths.  Everyone does their tool paths somewhat differently, so I am going to be very brief on this step.  Before you start making the tool paths on the front, go to the back of the stock and make the pocket for the clockwork.  Yes, this means that you are going to have two different programs, unless you make one where you need to flip the stock. We are going to make the finishing contour to cut out the body outline from the front, so do the back details before you do the front.  When you machine, start with your biggest tool to do the rough work and do a finishing pass with your smallest.  This will make your cycle speed go much faster and it will give you finer detail around the edges.  Also, make sure the zero is on the same corner for both parts so that you know where to zero the mill.

Chuck your stock in the mill and MAKE SURE IT'S LEVEL.  Clamp the stock very tightly.  Vibration can ruin a machine like this and a loose piece of aluminum in a mill with a spindle spinning at several thousand rpm is a dangerous combination.  Once your stock is clamped down, put whatever tool you use to zero your stock with in the holder.  Move the z-axis down until it is about .25" above the stock and then adjust your x-and-y-axis so that it is directly over the corner that represents the zero on your computer program.  Once you have it above the corner, take a piece of paper (old presentation pamphlets work great) and adjust the z-axis VERY SLOWLY so that the paper starts to scratch when you move it between the tool and the stock.  Your part is now zeroed.

Once your stock is set up in the vise and ready to cut, go to your tool path program and extract the G-code for your program that cuts the back pocket.   This is the line-by-line code that tells your machine what it needs to do.  There are several types of commands for G-code.  The actual G codes are codes for movement, such as the an arc, a line, a rapid move, or setting an offset.  These codes are represented by a letter and then a number, such as "G01", which is a standard movement.  These commands are followed by coordinates or other measures such as spindle speed.  But anyway, let's get back to cutting our part.  We are cutting the back pocket first because when we cut the front we are going to be cutting it all the way out, so import your G-code onto the machine from your computer and start the cutting the back pocket.  If your machine can spray lubricant, use that so that your part ends up with the cleanest cuts.

Once your part is done, remove it from the vise.  Flip the stock over and clamp it back in the stock so that the front is showing.  MAKE SURE to re-zero the stock and make it so that the program matches the way the back pocket is pointing.  So if your back pocket is pointing up, make sure your part will cut in the same direction.  Now take the G-code from the front of your part and put it on the machine.  Start cutting.  When I cut my part, the depth was wrong for the contour around the edge, so we left the stock in and changed the depth of the contour to get the part completely cut out.  However, we stopped the part before it got cut out completely so that the stock would not bend when the part fell through.  If we let it fall through, the part could have bent downward, a) causing the tool to be moved and possibly break and b) damaging the part.  So we kept the part in the stock held on by a tab.  Simply break the part out of the stock and file around it.  

Once your part is out of your stock, there are some sharp edges and parts missed by the tool.  File these down and do some fine tuning to the edges.  If you are sand-blasting your part, don't worry about scratches on the surface too much.  If it left a wall of foil on the bottom edge, just peel that off with a pliers and clean up the edges with a file.  Many of the small places on the edges got missed, so you can clean those up too. Once this is all done, put the clockwork in and screw all the parts together to see how everything fits. Mine looks pretty nice =D

Take your 3D file for the eyes and put it on a 2D drawing file so that you can see the front view of the gear.  Save the gear as a 2D file and put it on a plasma cutter.  Put two gears next to each other so that they will cut without interfering.  Cut out your gears!! Once they are cut out, don't just go grab them with your bare hands!!! Go get pliers or some welding gloves to get them with and then dip them in water.  Just don't burn yourself.  I'm not responsible for you hurting yourself in any way.  Once they're cut out and cooled off, you can hammer off the slag with a mallet and a punch, but I left mine on because it gives it some cool character.

Okay, so all of your parts are there, you just need to assemble!!! Start by taking a 1/4"-20 tap and tapping out the holes.  TAP SLOWLY, and if you do, use a cutting fluid of some kind.  The last thing you want in your perfect part is a broken tap (coming out of the EYE, mind you). Once the eyes are tapped, take two short 1/4"-20 screws and attach the eyes to the part with them.  If you want, you can loosen up the screws for the eyes and let the gears spin freely, but I tightened mine up.  Now that you're done, hang it up in your room next to a Woodstock poster and let the time fly by (owl pun!!). I hope you had as much fun reading this Instructable as I did making the clock.  And if you like it, VOTE in the Make It Real Challenge!!  =D