Making Cute Puppies with the Laser

puppySketchMy 5-year-old son came to me asking me to make him a wooden doggy.  I started drawing doggies on the back of an envelope.   He kept rejecting them.  Finally he told me that he really wanted one with a “mouth like an upside down Y”.  At least he was specific.  Finally we got a sketch that met with his approval. I assumed I’d make the doggy on the bandsaw and put details on using my trusty wood-burning pencil, since I’ve done a number of projects like that.  It’s always fun to semi-free-form cut on the bandsaw and improvise the shapes.  The width of the blade forces you to use broad curves, and the actual cuts in the wood are often nicer then the pencil lines you drew.

puppyPartsOnLaserFor the past few weeks, my Tech Shop night has been spent on a super-complex laser cutter project. The kind of project that won’t be finished for months with rounds of test assemblies. I realized that a purely aesthetic micro-project in the form of a cute puppy dog might be the perfect counterpoint to such a technical project. So I abandoned my original bandsaw plan.   I could get some finished objects with only about an hour of Illustrator time and some scrap 1/4″ plywood.  I could even glue them up while my next round of complex parts were being cut out, so I wouldn’t be  stealing too much time from my other project.

puppysNotFullyCutThroughThere was a bit of a glitch in that laser power output was a bit lower than usual. Wood is not an entirely uniform medium, so if you don’t have enough extra power going in, you end up with some uncut fibers.   Some of the pieces dropped right out, but a few needed to be cut free with my trusty Swiss army knife.  The tough fibers also tend to make the edges not a perfectly uniform burnt-wood color. If you care, you can touch those up after the fact with a wood-burning pencil. You can also sometimes get the pieces to come out cleanly if you sand the back of the sheet.  That way you don’t have to touch up the sides, but it’s a lot of sanding. And isn’t the best solution for plywood since you run the risk of sanding through the top ply.

puppyTwistThe nice thing about purely aesthetic pieces is you can glue them together any way you want.  That gives each puppy their own personality and lets you discover fun combinations.  I used some plywood that had one face a bit darker than the other.  I figured that would make puppies have a nice light underbelly.  The only down side is that they look a bit strange from the back.  I guess if you really wanted to make a bunch of these things, you could  cut the back legs/belly piece from plywood that was lighter on one side, then cut the head/forepaws parts from more uniform wood.

puppyBackAndSideBlueI knew that the pups would be a bit head heavy, but I thought when I glued them up, I could adjust the exact position of the hind legs so they would slightly lean back.  The only problem with that plan was that the two main contact points are only 1/4″ apart so they are  a bit tippy.   I considered scuffing them on sandpaper to give them a firmer foot hold, but then their paws would have bright flat spots on the bottom.  So I decided not to bother.   Puppies are tippy. That’s just the way they are.

threePuppiesWithBlueWallI glued one of the pups with his head down low, so he’d be the runt of the litter.  For some reason that also makes him seem a bit fatter.  I rather like this idea of cute parts that can be glued together in different configurations.  These have happy tails, but they could just as easily have sad ones.  This micro-project had a great effort-to-fun ratio.  Simon really loved his little wooden doggy: he loves the burn wood smell and thinks it’s cool that it was cut with light. He took it to school to show his friends. I haven’t really told him his pup has some brothers and sisters.  Here’s a family photo.  I could have sanded them to give them a crisper look, but I like the smudges and burn marks.  It gives them a bit more personality and it’s less work too.


Pastry Cutter Final Results

backingPlateCloseUpAfter finally getting the last parts cut on Dec 23 I had to go into a fabrication frenzy.  I was constantly ducking out into the garage to do the next round of glue and/or paint.   One of the real tricks with these cutters was getting the push plate positioned really accurately inside the cutter walls.   There was no positive alignment when I glued the cutter walls to the top plate.  If the push plate was off by much the plate would bind against the wall and stick.   Here you can see the system I came up with.  I glued up everything else, and positioned the backing plate on a scrap rod.  Then I just put in a few drips of solvent on the backing plate, and plop on the push plate.  I had enough time to position it exactly and then let the solvent do it’s work.  I left the protective paper on the under side of the backing plate so there was no danger of a stray drip of solvent fusing the backing plate.  This system worked great, but it did  mean that the parts weren’t interchangeable.  That really didn’t matter much.

moominSpringI cut some springs/push rods.  I needed them to be just the right lengths so the spring would still exert some upward pressure when fully up, but would bottom out before the push plate could be pushed all the way out of the cutter housing.   That protects the assembly and makes it hard to apply a lot of sideways or pulling forces on the push plate.    I used 1/8″ tubing instead of rod so the glue could bind to the inside of the tube a bit.  It also makes it so you can fill the hole with glue, and when you insert the tube the extra just goes up inside the tube instead of squirting out all around.  I chose stainless over brass to be more food safe.   The springs aren’t stainless though, so they really shouldn’t spend too much time in contact with water.

Moomins ClampedOnce I had assembled and glued the cutters they had to be clamped to keep the springs from tearing them apart before the glue was fully cured.   Here you can see a two Moomins clamped in the jaws of a big Jorgensen Clamp.  Don’t worry.  I was gentle.   I managed to get them all done in time for Christmas *phew*  but I did end up having to give them away 100% untested.  Eek!

moomintrollCutResultsThe day after Christmas I finally got to take them for a test drive.  I had had to make the cutting walls a bit thicker than I would have liked, in order to have enough surface area for the solvent welding.  That made it so you have to push down a bit harder than with the comercial cutters, and give a little bit of a twist or your Moomins end up with a paper thin fringe, but ultimately they worked fine.  Giving gifts I hadn’t fully tested was a  bit hair raising, but it all worked out in the end.

The details were crisp, and after some baking so were the Moomins.  Mission accomplished!

Pastry Cutter Progress

In this project I only had two disasters.  I often keep my projects in sewing boxes because they’re cheap, stack well, have semi clear sides (so you can see what’s in them), and have nice rubber handles.    The down side is that they do not have locking lids.   That used to worry me, but in all the years I’ve been using them it had never bitten me.   Until this year.   I was hauling the box out of the trunk of my car when one of the latches caught on my jacket pocket, and dumped everything out into my driveway.  In the dark.   In the pouring rain.     Trying to find tiny clear plastic Moomin facial features in that torrent was no fun.

The other disaster was more burocratic.   I have Wednesday nights to do these kinds of projects.  It’s my night off from being a Dad and I often spend it at TechShop.   Normally booking the laser is pretty easy, but in the run up to Christmas the schedule gets filled up by busy Christmas Elves.   This year I forgot to make one of the weekly reservations and was suddenly looking at doing much of the lasering on the day before Christmas Eve.  That put a big kink in my gluing schedule.

snufkinGlueUpI used two kinds of glue in this project.   Most of the parts are bonded using acrylic solvent welding, and the bond between the metal push rod and the plastic cap/base was done with J-B Weld’s Kwik.  I knew that aligning and solvent welding the thin “outline” parts that form the cutter would be a pain, so I laser cut a wooden form that could be placed inside the sections and force them to stay alighted while I applied solvent around the edge with a syringe.  Not being plastic I wouldn’t have to worry about them getting glued in place.   I also made the alignment pieces have some “cutouts” so  those sections would be easier to get in/out and wouldn’t pull solvent away from the plastic pieces via capillary action.  The only downside was that these forms left a small amount of black charred-wood-crud on the insides of the cutters, but most of that could be removed by the light sanding I needed to do anyway.

moominStampPartsI made Moomintroll’s face out of a lot of tiny separate pieces.   I figured that way each Moomin face would be slightly different and that would be nice.  What was less nice was the large amount of time spent positioning every eye and eyebrow with tweezers, and the addition time needed for swearing every time my syringe full of solvent knocked one of those tiny little pieces out of place.   On the other designs I grouped the pieces together.   Snufkin only has his face, pipe, and hat feather.  MUCH easier to position and glue.   When I suddenly was faced with a week less time to do this gluing I decided to build something to make the gluing go faster.    I thought “what if I build some sort of vacuum clamping setup?”

vacuumClampI wanted something that would hold the parts in place as the solvent did its work, and also let me see what was going on in case something got knocked askew.   I got a fish tank air pump, reversed the valves so it was sucking instead of blowing, and used that in conjunction with two 1/4″ acrylic sheets and some weather stripping to make a vacuum clamping area.   I thought  “I can apply the solvent, put the cover on, turn on the pump, and I’ll be able to see everything.   This is the sort of desperation that comes from suddenly loosing a week of gluing.

Was the vacuum clamp a success? As it turns out the weather stripping leaked enough to make the clamping action very slight, but it did make a nice clear box with just enough clamping action to hold the facial features in place while I then piled a big heavy chunk of metal on top to provide the final clamping pressure.  So all in all I judge the vacuum clamping chamber to have been a “modest success” instead of a complete waste of time.

snufkinPaintedGluing and painting.  To make the images of the characters on the tops of the cutters I laser etched the designs though the acrylic’s protective paper. Then I used a piece of rubber to squeegee the paint down into the etched areas.  Finally once the paint has dried some I peal the paper way.  It’s best to do that before the paint has fully dried because the fully cured paint is stronger and pulling the paper away can pull bits of paint out of the design.  When the paint is still weak it comes away clean.

Making Custom Moomin Pastry Cutters

moomintrollAndLeafEvery year I do some sort of Big Christmas Project.  This year I decided to keep it kind  of low-key.   We have some pastry cutters in the shape of leaves.  They’re nice because they let you stamp the veins of the leaf on, and cut the leaf out in a simple sequence.  When we make pie we often also make “Cheese Leaves” from left over crust so the kiddos can have some fun stamping them out, and sprinkling on cheese.  That way they also get a tasty snack long before the pie itself is done. I thought it would be nice to make some of these awesome cutter/stamper in more personalized fun shapes.

I’m a big fan of  Tove Janson.   My mom read me many of her Moomin books when I was a kid, and I have in turn read them to my kids.   Tove Janson’s illustrations are fantastic, and The Moomins have a nice way of dealing with life.  When a flood traps them on the second floor of their home they don’t moan and complain.  They cut a hole in the kitchen ceiling and marvel as seeing  that room from a new perspective.  They take turns diving for breakfast fixings.   I decided it would be fun to make some Moomin themed pastry cutters.

I knew I could make food safe parts out of laser cut acrylic, and I went to work in illustrator making a prototype out of clear acrylic scraps.  I had to see if quarter-inch acrylic could be stacked and glued to make the fairly deep cutter.  Here you can see the rough initial prototype of the Moomintroll cutter next to the commercial maple leaf that inspired this project.

Making a Egyptian Retro Technology Labyrinth Game

When I was young we used to spend time at my Grandparent’s house.  It was a farm house with a porch swing and there were lots of fun things to do.  My Grandfather would tell the story of my first trip around the yard on the go-cart.   I was very young and when I came back around I told him I’d “never operated a motor vehicle before!”  and he thought that was hilarious coming from such a little kid.  There was a mini bike (until we broke the front fork doing jumps) we played Jarts, yes all sorts of “dangerous” distractions.

One of the fun things we’d do is play an old wooden Labyrinth Game that they had.   We played it so much that we could run the ball all the way though and all the way back.  We played it so much that we tried playing it with our feet.   One day one of the control strings broke and although Grandpa “fixed” it he wrapped the string around the wrong way. Reversing that control, and permanently invalidating all our muscle memory for that game.

The Idea

Though TechShop I have access to a laser cutter.   Each year I build some sort of crazy Christmas Project, and this year I decided that a Labyrinth Game would be an awesome thing to make with the laser.   I decided on a Egyptian with a retro-technology flavor. (To fit in with the Secret Society theme I’d been following for a few years.)  I went with the kiddo’s to the local Rosicrucian Museum to do some first hand research.  I went to Toys R Us to see if they had one of those games.   I talked to 4 people there and non of them had any idea what I was talking about.   I then went to a smaller local toy store and the guy knew at once what I was talking about, and he had them in stock.   This more modern instance of the labyrinth had the same design (same hole pattern/course) but had been cheapened in a number of ways.  The metal balls were smaller, but the course had not been fully adjusted for that size change, which made some shortcuts/cheats possible.  I was able to finish the maze on the third try though, so my muscle memory from 25 years ago seemed good.   It was only $21, so you can’t expect much at that price point.

The Design

I started in on the design, I wanted to make a lid for the maze so it would come as a decorative wooden box.  I was originally going to put brass clasps on the lid, but eventually had to abandon that plan because of time constraints.  It would both cost a lot and I’d have to strip/age the brass fittings, and I was planning to build 6 of these things so it was better to keep it simple.   I did some sketches, and looked at Egyptian Art.   I noticed that the Scarab was a nice fit thematically since he’s such a famous ball roller.  (Although this project didn’t involve any dung.)

I had bought a lot of very thin wood from Minton’s in Mountain View when they went out of business, so I decided to do an inlaid wood Winged Scarab on the box lid.

Normally with these projects I do 4 of them by Christmas Day, but then have 2 others I finish up before New Years.  (For out of town folks where the timing isn’t as critical.)   However when I started working on this one I realized that the physical size of the project was going to require more laser time then I was used to using.  It takes a full hour to etch the scarab on the lid.   So I quickly realized I wasn’t going to be able to schedule enough laser time before Christmas to cut/etch all the parts needed for all 6, so for the first time I limited much of my part cutting to the basics I’d need for the first 3 and then I’d cut the rest after Christmas when laser time is a lot easier to schedule.

Scarab Deep EtchThe 60watt laser deep etching the scarab into the lid.

Scarab With BallThe laser etched ball glued into the lid

Parts OrganizerThis is how I organized the parts.  They are laser cut, but I tape them down to the surrounding wood before I take them out of the laser. That way the uncut material acts as the parts organizer, then I can just slip them into these three ring binder page protectors.  Using this system one three ring binder can keep track of all 8 zillion parts.  As long as you never EVER pick up the binder upside down and dump everything out!  I put a big orange arrow on the front of my binder to help keep that from happening.

Glue Setup 1The main body being glued.

glueSetup2There are 88 pieces for the wing segments alone, so it takes a while to glue up.  After the parts go in I clamp them down to dry.  The pieces aren’t a super tight fit, so hopefully that’ll leave enough room for expansion/contraction of the wood.

Fully Populated LidIt is ready to clamp, but I didn’t clamp this first one.  It’s always a learning experience, so this one was never fully flat/level.  Later ones were better in that regard.  I had 3 mistakes in the wing segments.  (two parts were swapped, and two were actually the wrong shape)  So I had to figure that out, and cut extras.  Once all that was ironed out things went more smoothly.

Three ScarabsA shot of the very first prototype in normal plywood, and two of the final ones in the 1/4″ Mahogany Ply that I got for the project.

Lid First CoatThe lid after being glued to the sides and with it’s first coat of Linseed Oil.

Inside Corner Of LidThe inside of the lid before finishing.  I wasn’t too happy with these two corners. They align the lid to the base, but don’t look that great.  Later I tried a bit fancier shape/look.  the little right angle brackets with the holes are nice and fancy looking, and quite simple to do.  Of course that’s 8 more things you have to glue in (two on each side of the lid.)

Side Of Box Mocked UpThe lid sitting on one of the sides just to show how the wings will work.   this is before I started the Linseed Oil finish work.

Side With KnobThis is one of the sides laid out with one of the knobs.  Above you can see the zip lock bags I used to organize thick knob segments.  I made the knobs from three segments of 1/4″ wood plus a very thin wood layer for the eye.

Knob PartsThe knob is made up of 4 parts. You can kind of see the funky strait knurl.

Knob Glue UpI glued the knobs up on a brass rod held in the lathe’s chuck, so you can make sure the rod would be plumb.  Otherwise the stack of laser cut parts is bound to wobble as it turns.  However you could just as easily do this with a piece of brass rod stuck into a hold that was drilled plumb.  There’s no real need for a lath with this project.  It was there, and that made it easy.

Knob On LatheYou can see a little to much glue sticking out of one of the glue joints.  It’s nice to wipe it down with a damp sponge to reduce the amount of glue visible.

Joined CornerHere’s an early test cut of the corner joint. The laser cuts in a slight V shape, but you can compensate for that a bit by shaping the fingers into actual dove tails.  (Thanks Heath for the idea!)  However you can only do that in one direction if you try to compensate in two directions you get a tight joint that needs a teleporter to be able to assemble it (since there are then wide fingers on the outside of each joint)  I guess you could do it the other way around, and have 2 axis fixes for both joints with reverse dove tails, but then I would have had to flip the wood over after etching but before cutting, which would have been an alignment hassle.  The joints where plenty tight as it was.  This test is using Cedar, but I ended up using Alder which has a less pronounced V shape to the laser cut.   (And which I could get locally at Home Depot)

Ball Outlet DetailHere’s a final corner with a detailed look at the ball exit.  The bottom part of the box extends to create the ball return area.  That makes it much stronger since there’s 1/4″ plywood supporting the return area instead of something just glued onto the side.

Beginings Of Mass ProductionAfter the design was done I had to crank up for mass production.   Here are the sides/lid sides for three boxes (well minus the lid sides for one.) A set of 2 sides takes about 15 mins to etch/cut out on the 60Watt laser.

Tilt Floor Wedges Glue UpHere’s the design of the box floor.  It has 3 wedges which will hold the tilted floor that makes the ball go to the exit. You can also see the 4 screw holes since the floor needs to be removable for possible maintenance.

Tilted Floor After Glue UpI sanded the bottom corner of the tile floor so that it can smoothly go down to almost nothing at the exit port.

Ball Defector DetailI do however have to provide a special corner piece to keep balls from getting stuck behind the post that the screws screw into.  In theory the ball could still fall onto the upper corner of this piece and get stuck, so if you really cared you could sand the top to be slightly curved, but the chance of that happening are small enough that I just don’t care to do the extra hand work to handle that case.

Ball Deflectors Glued InHere you can see three of those corner pieces getting glued down.  The middle tilted floor was the very first floor, using different wood.  On some of them I also sanded a slight dip in the top of the plywood at the exit, but that turned out not to be necessary and it doesn’t look that great.

Tilted Floor In PlaceHere you can see the tilted floor in place.  You’ll notice that the blocks glued into each corner (so the base can screw into those blocks) have tops that are cut at an angle to make it so the ball can’t get stuck on top of one of the corner blocks. You’ll notice that in this fit up I don’t have the special corner piece glued in yet.

Spring Winding RigI decided to wind my own springs for this project.  Mostly because I couldn’t find the right quantity of the right size/tension of spring locally.  This wasn’t that hard to do, but was a bit of a time sink.   Here you can see me using a Jorgenson clamp to tension the wire as I hand crank the lathe to wind the wire into this brass rod.  That is the easy part.  The annoying part is then cutting/forming the ends on the wires.

Hand Wound SpringsHere you can see two of the better resultant springs.   I used a dull Exacto blade to spread the coils enough to get in and bend the loops the rest of the way out with pliers.  After the first three were built I had some time after Christmas and found some suitable springs at Tool Land, so I only had to build the first 6 springs, not all 12.

bushing Pressed Into Wood FrameI used brass tubing pressed into the wood to form bushing for all the brass rod joints, this makes for super smooth action and long life.

Hot Glued Saw Stop For Cutting BushingsHere you can see me cutting a bunch of the bushings.   I used this super cheep Harbor Freight micro chop saw, and hot glued a stop to the saw at the right distance.  That makes it super easy to cut 20 zillion of these things.   Note how the stop is angled and only touches the edge of the tube, so it doesn’t cause binding when the tubing cuts through.  After you’re done with the stop you can just pry it off of the saw.   Some day I’ll make a fancy tubing holding/adjustable stop system, but this works well as long as you don’t have to do too many different sizes, and it could just be used in the saw as-is.  I didn’t have to dive into an extra project rat hole.

Control Rod Bushing CloseupHere you can see one of the bushings in place around the rod.

Brass Bushing And SpacerI also made a number of pivot pins using a round wooden washer and a bit of tubing.  You can see one here (blurry) ready to go into the hole.

Maze Frame ClampedHere you can see a frame getting glued to the maze floor.  I laser etch the locations of all the wall segments, and put numbers in them so I know which pieces go where.  There’s also an arrow, and hazard numbers for the game itself.   Notice how I used scraps of wood that were cut from the jaggy edge areas as clamping sections so the clamps wouldn’t damage the pointy parts of the wood.   The first one of these I did I didn’t do that, but used padded spring clamps, but there was some slight damage done, so I switched to this system.  There are about 45 pieces that get glued down to make the maze.

Mostly Populated MazeHere is the maze partially populated.  I didn’t bother to number unique segments since there aren’t a lot of them and it’s easy to keep them strait.  In the upper right you can see the piece of wood that the parts are coming from.  The parts are numbered in columns from top to bottom 13 to a column.

Maze And Parts SheetHere’s a closer view including the now fully empty parts sheet.

Maze Texture Closeup 2The walls of the maze have this herring bone texture on them, including miters at the various intersections.   The circular arc wall segments have a slightly bigger pattern because it was a pain to get them distributed along the circles in Illustrator.  I think I could do a better job now knowing more about pattern brushes, but I was just using the Offset  Effect, and getting that with perfect spacing was a pain.

Maze Miter DetailsSome of the miter work on the maze walls. Lots of tiny herring bones.

Eye Knobs On LidHere are some more parts glue drying getting ready for assembly.

Washers And WedgesHere you can see how easy it is to make a mess of wooden washers (left) and wedges for the tilt floor (right).  This is enough for all 6 labyrinths.

Staple Gun With Brad SpacerI was originally going to drill/bend brass wire loops to attach the drive train to the pivoting frames, but that was going to take FOR EVER to do, so I opted to just my staple gun.  This was terrifying because I was stapling into fully finished things on Christmas Eve.  So being off and having a staple come splintering out would be VERY bad.   So I practiced on some scrap first.  I used this brad to keep the staples from fully seating so you could then tie strings/ attach tensioning springs to the staples.

Spring CloseupHere you can see one of the springs attached.

String And SpringAnd the way that the spring tensions the string as it wraps around the rod.

Both Rods In PlaceA closeup of the two rods in place with the strings on and tensioned.

Fully Strung Maze From BottomThat’s the full view of both rods in place and strung up.

Bucket Of EyesThe knobs for the first size mazes are sprouting like strange flowers from a pink bucket.  (glue drying stand.)

Set Screw CollarsMy brass control rods are 5/32″.  Thankfully they make 5/32 locking collars for some sort of hobby use, so I was able to buy them for cheap.  Here are enough locking collars for two mazes.

Lock Collar In PlaceA closeup of one of the collars before I put the set screw in.

Knob Side ViewThis is a closeup of one of the knobs with it’s spacer washer and locking collar in place.

Brass Screw Next To FootThe bottom of the box screws into place just inside the corner feet that that box has.

Maze Boddy CompleteBoth frames and the knobs in place for the first time.  Time to play test!  The first play testing happened at 9pm Christmas Eve, so it was good that it worked because there wasn’t time to make any major changes.  I did end up re-tensioning things to deal with some stretch in the strings/knots.

Velvet Bag Stiched UpThen it was time to sew up some black velvet bags for the ball bearings to go in.

bag Sewing CloseupThere the bag is turned right side out.

Balls And Bag On Maze SurfaceThe three balls on the velvet bag.

Maze With LidThe maze opened up so you can see the maze surface.

I made a video of the laser cutting, and the kiddo’s playing with it on Christmas Day.

Maze With Lid On

The final finished box.   I managed to make 3 by 2:30 am Christmas Eve.