Tag Archives: cats

2014-05-11 11.42.03

And introducing: Cornelius

I real­ized that I’ve men­tioned this on Instagram and to a few friends, but have not yet made any ref­er­ence on this blog: I have a new kit­ten! His name is Cornelis!

He was born on February 21st at Enchanted Sphynx. I vis­ited him and his brother about a month ago.

porshamale2_003

And he came home two week­ends ago. It was an inter­est­ing road trip:

2014-05-03 14.29.28-1

We’re still get­ting fully set­tled in. He absolutely adores Norman, the indoor/outdoor tuxedo that showed up semi-feral on our doorstep. He shad­ows Norman around and tries to play with his tail. For the most part, Norman is indif­fer­ent (except for the tail-playing, which he dis­likes). The Precious is a dif­fer­ent story. She hates change and doesn’t like him. She’s warmed up to him slightly over the past cou­ple of weeks, but is still pretty frigid. It took her a few months to get used to Ebenezer, but they even­tu­ally became best bud­dies.

Pictures!

Posted in: Dear Diary

2013-12-21 16.37.37-2

Ebenezer, 2003–2013

Some of you may already know from Facebook or Instagram, but Ebenezer, a.k.a. Fidget, a.k.a. Hypercat, son of Ted E. Bare and American Beauty, passed away on Saturday. He had been qui­etly bat­tling heart dis­ease his entire life, occa­sion­ally seen as strong heart mur­murs, but offi­cially diag­nosed about 6 months ago as an enlarged heart.

Ebenezer-2003_to_2013

At the time, he coughed a lot. He coughed in that wheezy trying-to-release-a-hairball sort of way. Of course, this was highly unusual for a naked cat. After it didn’t go away on its own, we brought him in to the vet. An ultra­sound con­firmed his heart was not only over­sized, but push­ing on his lungs. There was a lot of fluid in the lungs as a result. Without inter­ven­tion, his remain­ing time would be mea­sured in weeks. They hooked us up with heart med­i­cine (cat-sized doses of actual human heart med­i­cine), with a guess of another year or two until reach­ing his expi­ra­tion date. Things improved and he was mostly back to nor­mal. Perhaps not as much of a race-around-the-house, cat-tree-climbing mon­key as he was prior, just a slightly older ver­sion of him­self.

A lit­tle over a week ago, he had an episode. He had been sick for a cou­ple of days, prob­a­bly from a kitty-cold that Norman brought in, and hadn’t been eat­ing. We’d also had dif­fi­culty feed­ing him his pills. He yowled a cou­ple of times, had dif­fi­culty breath­ing, and wouldn’t move from the spot where he planted him­self on the floor. It was after-hours for our nor­mal vet, so I took him to the ani­mal hos­pi­tal. They rushed him to an oxy­gen cab­i­net and took some x-rays. The out­look didn’t look too good. There was a lot of fluid in there. They were look­ing at the pre-existing con­di­tion com­pounded by pneu­mo­nia.

Hangin' at the exclusive (and expensive) oxygen bar
Hangin’ at the exclu­sive (and expen­sive) oxy­gen bar

Miraculously, he was released the next morn­ing with a rea­son­ably clean bill of health. There was still fluid in there, but they were able to coax out a good amount with med­ica­tion. He was happy, chirpy, and feel­ing bet­ter. More impor­tantly, he was eat­ing like a horse — a very good sign.

One of the last pictures I ever took of the lil' guy. Resting between the hospital and regular the vet.
One of the last pic­tures I ever took of the lil’ guy. Resting between the hos­pi­tal and the reg­u­lar vet.

Our reg­u­lar vet checked him out later that after­noon, since she was more famil­iar with his case his­tory, and altered his meds to com­pen­sate for his weight loss, but thought he was recov­er­ing pretty well. The whole week, he was happy to eat food, drink water, and he was finally get­ting all his meds.

My hope was that he’d make it through Christmas. In fact, I’d assumed that would be the case. My real hope was that he would get through the chill of win­ter, to see another sum­mer — every naked cat’s favorite time of the year.

This Saturday we had an even worse episode. Some howls of pain, retreat­ing to the cat­box to puke, and when he got out, he flopped over on the wood floor of the next room, rolling around but oth­er­wise unable to stand or yowl. I rushed him back to the hos­pi­tal. I talked to him the whole drive because the typ­i­cal howls of cat-carrier-travel protest were more like whim­pers. Unfortunately, there wasn’t much they could do this time. A lit­tle after 2:30pm, I made the rough call to put him down. The oxy­gen wasn’t help­ing. He was pretty far gone and not really cog­nizant of his sur­round­ings. I sat and talked to him through the whole thing, hop­ing some part of him could still hear me despite the oth­er­wise lack of response.

2013-12-21 16.37.37-2

The last cou­ple of days have been pretty rough. There is most def­i­nitely an Ebenezer-shaped hole in my life. I started to make a list of the things I’ll miss, but it quickly spi­raled out of con­trol. Here is a brief snap­shot:

His smell. It’s nei­ther pleas­ant nor unpleas­ant, but it is present. You’d occa­sion­ally catch a whiff of it, either directly from him or from the blan­ket he’s been hud­dled in. He was a sweaty cat with a mild odor that I can best equate to the fur and sweat of horses on a sunny after­noon. It gets stronger over time, espe­cially when he turns a blan­ket into a sweat-lodge, which is why I gave him a bath every week or two.

Leave the bath­room door open, and he’d join you in the tub when you’re show­er­ing. Leave it closed, and he’d be wait­ing when you leave so he can lick up water drops from the bot­tom of the tub.

The heat vents that dou­ble as a cat perch.

His love of peo­ple, love of being a ham, never shy­ing away from atten­tion. He knew he was the star of the show when strangers are around.

His favorite spot, when the sun porch is cold or inac­ces­si­ble and there are no peo­ple around to per­form in front or sit on top of of was this mangy igloo, despite the really nice one perched on a heat vent. I think he liked the warm hug that the furry insides pro­vide:

Left: “this mangy thing”
Left: “this mangy thing”

Having to check every blan­ket before you sit down, to ver­ify the lump you see isn’t him. And hav­ing to warn vis­i­tors of the same.

The lit­tle guy rac­ing down­stairs to meet me when I got home, like a puppy.

The con­stant open/close slam­ming of the cab­i­net door when it’s food time. I actu­ally started miss­ing this about a month ago, when I installed soft-close cab­i­net dampers. He kept on try­ing to slam the food cabinet’s door, but it no longer made noise.

The “kitty siren.” This is the only cat I know of who, when it comes time to puke, had an early warn­ing sys­tem. He’d occa­sion­ally eat too much grass or slurp up a hair when drink­ing from the sink. If you heard that siren-like yowl, you had about 30 sec­onds to grab some paper tow­els and have them ready in front of him. He’d then puke twice (always twice) onto the paper.

His total and absolute indif­fer­ence toward cat­nip, but his love of the smell of bleach and his rolling-around on freshly-bleached bath­room tile.

That expres­sive face, with no fur to mask that expres­sion — you could instantly see con­fu­sion or dis­taste as it reg­is­tered. Happiness was a lit­tle more elu­sive to visu­ally spot, but you don’t need facial tics for that. A warm purr is suf­fi­cient.

The pointy way he sat. Based on pho­tos of other cats, I think this may the whole Sphynx breed and not just spe­cific to him. When he sat on a lap or chest, he’d be perched to spro­ing, with all of his weight on the pads of all four feet — not even sit­ting fully flat on the back feet. Physics and pounds-per-square-inch and such dic­tate that this gets extremely uncom­fort­able for the provider of the lap or chest. He would occa­sion­ally pan­cake out flat, but that was a rare occur­rence.

Always want­ing to touch some­body at night, with skin-to-skin con­tact. In win­ter, it’s nice to have a cat-shaped “hot water bot­tle.” In sum­mer, it’s less pleas­ant to have a sweat­mon­ster under the cov­ers. Although some­times the con­tact was of the pointy cut-off-circulation-to-your-arm vari­ety, he always wanted human con­tact.

 

✻ ✼ ✻

 We’ll close with a few of my favorite pho­tos of the lit­tle dude...

Svveatercat sphynx_in_natural_habitat IMG_1070 IMG_1888.JPG

 

...and a slideshow of him over time, start­ing when he first arrived home:

 

IMG_1862.JPG IMG_1876.JPG IMG_2336.JPG IMG_2330.JPG IMG_1905.JPG glasses_ebenezer IMG_1901.JPG cuddle IMG_4225 Squirrel Watching 2 IMG_3108 QuickTime Player 7001 IMG_5567 IMG_5144 IMG_4237 IMG_3343.JPG IMG_2653.JPG 11-ebenezer IMG_0019 2013-09-16 21.13.09 2013-05-06 23.50.38-2 IMG_2395 IMG_0575 IMG_2697 IMG_2521 IMG_1289 IMG_0078 IMG_0012 2013-03-18 20.54.44-2

Feel free to look through the posts tagged “Ebenezer” for more detailed sto­ries of his antics.

 

Posted in: Dear Diary Pictures

scoop

Choose your own measuring cup

scoopAbout a year ago I designed and printed a 1/4 cup mea­sur­ing cup.  You see, I needed a good way to mea­sure cat food.  I only needed the one size, so buy­ing a whole set of mea­sur­ing cups seemed like a waste.  With a MakerBot in the other room, I fig­ured it was best to make just the one size of mea­sur­ing  cup.  It worked well, but the han­dle recently broke off.  I took this as an oppor­tu­nity to not only design and print a bet­ter one, but to share it with the world.

I crafted the orig­i­nal ver­sion in OpenSCAD and para­me­ter­ized some of the vari­ables.  The new Thingiverse Customizer makes these vari­ables more acces­si­ble.  Instead of down­load­ing a script, edit­ing it to plug in your own val­ues, then run­ning it through OpenSCAD to pro­duce an out­put file, you just twid­dle a few knobs in the web UI and down­load your file.

customized_measuring_cup

 

The design of each cup is such that the cup’s width and height are equal. This bet­ter facil­i­tates nest­ing them within one another, though the actual nesta­bil­ity is ulti­mately based on which sizes you have and how thick you make the wall.

If you would like to choose and down­load your own cus­tom mea­sur­ing cup size, check out the Customizer page: http://www.thingiverse.com/apps/customizer/run?thing_id=56508

scoop

Posted in: Code MakerBot

catfoodtoy-ovals-thick_preview_featured

The design and manufacture of a cat toy

Yesterday I taked about fix­ing a cat toy.  Today, I should briefly men­tion the one I designed a cou­ple of week­ends ago.  I’ve had the idea kick­ing around in my head for quite a few months to design a treat-dispensing cat toy.  Surprisingly, there is not one already on Thingiverse.  I sketched out a quick idea and fig­ured out some geom­e­try.  (Remember, kids!  Geometry and alge­bra are NOT lame skills you’ll never use in the real world!)  I mea­sured nuggets of cat food and treats with dig­i­tal calipers down to a tenth of a mil­lime­ter pre­ci­sion.

cat_toy_notes

From there, I drafted up some­thing in OpenSCAD.  Actually, I drafted up sev­eral things.  The first few design iter­a­tions were way too brit­tle.  I had to thicken the wall and reduce the num­ber of dec­o­ra­tive holes to give it strength.

After a few revi­sions, I ended up with some­thing strong, aes­thet­i­cally pleas­ing, and with enough holes in it that cats can see, hear, and smell the treats inside.  As they kick it around, it will occa­sion­ally dis­pense a treat.

The print­able files are on Thingiverse under “Food Dispensing Cat Toy.”  The source files are in a github project.

Posted in: MakerBot Projects

cat_toy_repair

Good news, bad news, good news, good news: cat toy edition

I stum­bled across a semi-forgotten cat toy last week.  It’s one of their favorites — it’s a motion-sensitive ball that lights up in a vari­ety of col­ors when kicked.  It also eats up bat­ter­ies.  It takes three watch bat­ter­ies, but I only had two left in the pack­age in my desk drawer.  They were super-cheap on ama­zon ($5 for 30 includ­ing ship­ping, whereas Radio Shack will typ­i­cally sell you a sin­gle bat­tery for $2 or $3).  I ordered 30!  Good news!

The bat­ter­ies arrived the other day.  I popped open the cat toy, went to insert three bat­ter­ies, and dis­cov­ered they’re too thick.  I got the wrong kind of bat­tery.  Watch bat­ter­ies of this kind are all the same volt­age, but in a vast array of phys­i­cal dimen­sions.  These had the right diam­e­ter, but were just too thick.  I’d acci­den­tally ordered bat­ter­ies for the kitchen timers — the only other things in the house that take watch bat­ter­ies.  Bad news!

I looked closely at the design of the cat toy cir­cuit board and bat­tery hold­ers.  If the bat­ter­ies were too thin, I could have bent the ten­sion tabs more for a tighter fit, but the bat­ter­ies were too thick, so there was not much I could do that didn’t require surgery.  The bat­tery holder design was pretty sim­ple, though, so surgery was not com­pletely out of the ques­tion.  I grabbed my trust Weller sol­der­ing iron and assorted other tools and hacked the bat­tery hold­ers.  Good news!

cat_toy_repair

Additionally, now every­thing in the house that takes a watch bat­tery (the kitchen timers and the cat toy) all take the same bat­tery!  There’s no need to stock two dif­fer­ent kinds.  Good news!

Posted in: Projects

montage

From Atoms to Bits to Atoms: A Cat Toy’s Journey

I thought I would fol­low up the pre­vi­ous cat toy post with another one. I’m not obsessed with cat toys!  Really!  They just make good geo­met­ric mod­els.  The main con­tent of this post will soon go into an Instructables page as an entry to win a 3D printer in the Make It Real Challenge, but I wanted to start with a copy here on my own blog.

There are some cat toys at the house that are par­tic­u­larly pop­u­lar with the local res­i­dents.  They are sim­ple hol­low spheres with cut-out slots.  They are great for kit­ties to kick around — small and light.  After star­ing at one for a few min­utes, piec­ing out the geom­e­try, I real­ized that this would make a great instruc­tional design for an intro­duc­tion to 3D CAD mod­el­ing using sim­ple geo­met­ric shapes and boolean trans­forms.

Before we begin, you will need two things:

  • A copy of OpenSCAD. This is “free” in every sense of the word — it costs noth­ing AND is an Open Source project that peo­ple from around the globe con­tribute to and use.  You can get it for Mac, Windows, or Linux.
  • A web browser tab open to the OpenSCAD User Manual. OpenSCAD works like a pro­gram­ming lan­guage and although I’ll step you through the process, it is always good to have a lan­guage ref­er­ence handy.

If you look at the orig­i­nal cat toy, it is a ball.  That is to say, it is a hol­low sphere (or spher­i­cal shell if you want to get fancy).  That ball then has slots cut away at reg­u­lar inter­vals.  I did a lit­tle bit of mea­sur­ing before­hand.

Let’s start by mak­ing the sphere. This is a sim­ple one line “pro­gram.” There is an extra line up top that you can mod­ify to pro­duce dif­fer­ent detail lev­els. I find that a value of 30 is good to do most work in, though I bump that up to about 100 when I am ready to pro­duce a final ren­der. This sphere has a radius of 20mm. Remember that the radius (20mm) is half of the diam­e­ter (40mm).

DETAIL = 30;

sphere(r = 20, $fn = DETAIL);

Type this code into the text area on the left of the OpenSCAD win­dow. Go to the “Design” pull­down menu and select “Compile.” In a few moments, you should see a sphere in the right half of the OpenSCAD win­dow. You can click and drag with your mouse to rotate the 3D shape and use the mouse wheel to zoom in and out.

If we were to print this sphere on a 3D printer, it would be solid.  We don’t want a solid ball, but a hol­low shell.  Let’s sub­tract enough away to give us a 2mm shell.  We do this with the dif­fer­ence() func­tion.  This func­tion takes a list of two or more objects, draws the first one, and then sub­tracts each of the other ones.  In this case, we will make a slightly smaller sphere inside and sub­tract it.

DETAIL = 30;

difference()
{
    sphere(r = 20, $fn = DETAIL);
    sphere(r = 18, $fn = DETAIL);
}

Now, select “Compile” or use its hotkey (F5). Note that on my key­board (a Mac), the F5 key is actu­ally key­board bright­ness and I have to use the “Fn” key to use it as an F5.

In the graphic win­dow you will see.... some­thing that looks exactly like what you had before. Except it is hol­low now. How do you know? Let’s take a quick bite out of it with a cube.

DETAIL = 30;

difference()
{
    sphere(r = 20, $fn = DETAIL);
    sphere(r = 18, $fn = DETAIL);
    cube(size = [20, 20, 20]); // temporarily use this to peek at the thickness
}

This pro­gram starts with the big sphere, sub­tracts out the smaller one, then sub­tracts out a cube.  You may have to use your mouse to rotate around, but it should look some­thing like this:

Now remove that cube line.  We will do some­thing very much like that to cut out the slots, except instead of cubes, we will use cuboids, which are the rec­tan­gles of cubes.  Let’s just start with one to see how to line things up.  We’ll do this:

DETAIL = 30;

difference()
{
    sphere(r = 20, $fn = DETAIL);
    sphere(r = 18, $fn = DETAIL);
    cube(size=[80, 40, 5]);
}

You’ll end up with a sphere with a slit sim­i­lar to a Cylon eye strip.  What’s going on here?  Shouldn’t that have cut out a rec­tan­gle?  It did, but the rec­tan­gle was placed directly on the ori­gin.  If you select “View -> Thrown Together” from the pull­down menus, then “Design -> Compile” you’ll see the com­bi­na­tion of shapes.  This is an extremely use­ful view of your vir­tual world when you are try­ing to sub­tract shapes and don’t under­stand what is going on.

We want it to com­pletely inter­sect from one edge of the sphere to the other.  To do that, we’ll need to slide it over a bit.  We can do that with the trans­late() func­tion, which takes the object fol­low­ing it and shifts it around on the x, y, and z axis.  Let’s try it.

DETAIL = 30;

difference()
{
    sphere(r = 20, $fn = DETAIL);
    sphere(r = 18, $fn = DETAIL);
    translate(v = [-40, 0, 0])
        cube(size=[80, 40, 5]);
}

That’s the strip we’re look­ing for, but it needs to be off­set just a bit from the cen­ter to give us that cen­tral sup­port col­umn.  Let’s tweak that y value over a lit­tle bit more.

DETAIL = 30;

difference()
{
    sphere(r = 20, $fn = DETAIL);
    sphere(r = 18, $fn = DETAIL);
    translate(v = [-40, 4, 0])
        cube(size=[80, 40, 5]);
}

That’s great!  Now we just need to add a few more!  I’m going to adjust the height from 5mm to 4.45mm to get them to divide a lit­tle more evenly across the sphere.  Let’s add some more trans­lated cubes.  It takes a lit­tle bit of math to get the posi­tion­ing right, but you can add one at a time, exper­i­ment with posi­tion­ing, and play with the results as you go.

DETAIL = 30;

difference()
{
    sphere(r = 20, $fn = DETAIL);
    sphere(r = 18, $fn = DETAIL);
    translate(v = [-40, 4, -20 + 2 * 4.45])
        cube(size=[80, 40, 4.45]);
    translate(v = [-40, 4, -20 + 4 * 4.45])
        cube(size=[80, 40, 4.45]);
    translate(v = [-40, 4, -20 + 6 * 4.45])
        cube(size=[80, 40, 4.45]);
}

Finally, the other half of cutouts goes in, off­set from the first set.  The code looks almost exactly like the first half:

DETAIL = 30;

difference()
{
    sphere(r = 20, $fn = DETAIL);
    sphere(r = 18, $fn = DETAIL);
    // right side
    translate(v = [-40, 4, -20 + 2 * 4.45])
        cube(size=[80, 40, 4.45]);
    translate(v = [-40, 4, -20 + 4 * 4.45])
        cube(size=[80, 40, 4.45]);
    translate(v = [-40, 4, -20 + 6 * 4.45])
        cube(size=[80, 40, 4.45]);

    // left side
    translate(v = [-40, -44, -20 + 1 * 4.45])
        cube(size=[80, 40, 4.45]);
    translate(v = [-40, -44, -20 + 3 * 4.45])
        cube(size=[80, 40, 4.45]);
    translate(v = [-40, -44, -20 + 5 * 4.45])
        cube(size=[80, 40, 4.45]);
    translate(v = [-40, -44, -20 + 7 * 4.45])
        cube(size=[80, 40, 4.45]);
}

Finally, you can crank up that DETAIL value when every­thing looks good.  This will give you a higher qual­ity 3D model with more sur­faces, but it takes a lit­tle longer to gen­er­ate.  Go to “Design -> Compile and Render” on the pull­down menu for your final ren­der.  Assuming that looks good, go to “Design -> Export as STL” to save it as a 3D file.  Most 3D print­ers and 3D print­ing ser­vices use this file for­mat.

Congratulations!  You cre­ated a cat toy using geom­e­try!  Time to print!

On a home 3D printer, even if you build using sup­port struc­tures, the upper slats will have grav­ity work­ing against them.  They’ll end up sag­ging a bit and kind of stringy on the bot­tom.  You will get a ball that is struc­turally sound, but looks a lit­tle warped.  If you have a small metal file or X-Acto knife, you can man­u­ally clean it up a lit­tle.  Industrial print­ers typ­i­cally do not suf­fer from this sort of prob­lem because they use a dif­fer­ent process for print­ing and sup­port.

I have a zip file (cat_ball.zip) con­tain­ing source for each of these steps.  It also con­tains a mondo-mega final OpenSCAD file called a para­met­ric model.  This is a model where all of the impor­tant num­bers are dis­tilled and extracted to the top (much like DETAIL is in the above exam­ples).  This then lets you eas­ily change the size of the ball, the wall thick­ness, the num­ber of slots, and the width of the sup­port struc­ture (i.e. the depth of the cuts).  You can then make all sorts of crazy vari­ants just by chang­ing a few num­bers.  You want one that is 50mm in diam­e­ter with a 5mm thick shell and 19 cutouts?  There you go!  But good luck print­ing this vari­ant on a home 3D printer.

 

Posted in: MakerBot Projects

Photo Mar 19, 10 08 07 PM

DIY foamcore cat toy balls

It does not take much to make a cat toy.  Often times, they will make their own toys out of stuff around the house (even if you do not want them to) such as shoelaces.  They like crum­pled up paper balls.  They like the plas­tic pull-off safety tab from the milk bot­tle.  They like chew­ing on the cor­ners of any ran­dom piece of card­board as well as books.  That fancy cat­nip mouse you bought spe­cial for them from the pet store?  They ignore it.

My cats?  They love to play soc­cer.  Toy balls, wadded up paper, cof­fee beans, hair ties, really any­thing small enough to kick around, lose under the stove, and attempt to fish out (some­times suc­cess­fully, usu­ally not) are things they enjoy.

A few months back, I did a secret project for Kim’s busi­ness.  Although it involved design­ing, mak­ing, and assem­bling some­thing, I did not blog about it.  Company secrets and all.  What I can say is that I had a bunch of left­over 3/16″ foam-core board.  Using the scrap, I thought I would try my hand at mak­ing a few cat toys.  These would be a good com­bi­na­tion of three things:

  • soc­cer balls to kick around
  • thick cardboard-like mate­r­ial to punc­ture with bites
  • large enough to not get lost under the stove

I think I suc­ceeded (and in fact, I hear one being kicked around in the other room right now).  The con­cept is sim­ple: just two inter­lock­ing cir­cles that slide together:

Simply print out the fol­low­ing pat­tern, cut out the circle-with-slit tem­plate, and use that as a guide for cut­ting foam­core with an x-acto knife.  Each toy ball requires two cir­cles of the same size.  The tem­plate has two dif­fer­ent size cir­cles to try.  My cats pre­fer the smaller one, but yours might pre­fer the other.

foamcore_cat_toy_balls.pdf

If you want to try mate­r­ial with a dif­fer­ent thick­ness, it’s easy enough.  It’s just a cir­cle with a slit whose width is the thick­ness of the mate­r­ial.  The thicker the mate­r­ial, the more rigid the result­ing “sphere” will be — in other words, you’ll want foam­core or card­board.  Cardstock or paper will be too thin.

Posted in: Projects

cat_scratchers_petsmart

Cat-scratcher cost-savings analysis

In the pre­vi­ous Cat Scratcher post, I for­got to include the fol­low­ing pic­ture, taken in a local PetSmart of sim­i­lar (but more cheaply made) prod­ucts:

The small cat-scratchers go for $10.  The larger, more fancy ones — the ones most sim­i­lar to the one I designed and made — go for $25.  In mine, the wood was $17 (though I have plenty left over for other projects) and the hard­ware was a few dol­lars.  I’d say I prob­a­bly broke even.

On the other hand, I have some­thing that looks a lot more fancy than the mass-produced scratch­ers, as well as one that I can eas­ily refill indef­i­nitely for free (as long as I have a few spare boxes and a sharp blade on the util­ity knife).

Posted in: Projects

The final product

Adventures in cat-scratching –or– how a laser project became a regular project

When you first start out with the laser cut­ter (for me, not in-person but via a ser­vice like Ponoko), it seems that everyone’s “hello, world” project is a set of coast­ers.  I have done a cou­ple of projects since then, but have had one in par­tic­u­lar in my eye that is actu­ally not that much more com­plex than the coast­ers.  As a raw mate­r­ial, cor­ru­gated card­board is extremely cheap, and we have a cou­ple of old card­board cat scratch­ers that I had to throw into the recy­cling, so I thought I would com­bine these to make my own cat scratcher.

The cat scratcher design I had in my head was noth­ing new.  I have seen many designs that are, effec­tively, lots of lay­ers of card­board sand­wiched between two boards, all held together with bolts.  I wanted to make some­thing like this tri­an­gu­lar design that I saw on ModernCat, but with a more wavy style, like this other one.

I did up my design, first on paper, then in Illustrator.  I cal­cu­lated how many lay­ers of “filler” are nec­es­sary with the thick­est card­board to make a nice big cor­ru­gated sand­wich.  In the end, I had designs that looked good at the time, but now that I see them side-by-side with the above wavy ver­sion might have been a bit too wavy.

Cardboard Filler
Wooden Ends

As I recall, I needed three copies of the filler laser-cut in thick card­board.  This par­tic­u­lar wooden-end design included one wavy pair with the cats’ names engraved, one plain wavy pair, and one square pair — this was mainly because I had a lot of excess space in the wood.  At the very least, I fig­ured I could use the extra pair of square ends to man­u­ally make a scratcher by maul­ing some card­board boxes with a box-cutter.

As usual, it took a few rounds of revi­sions to get Ponoko to rec­og­nize the design.  Their uploader, under­stand­ably, is quite picky about your files.  Etch lines must be the cor­rect color and thick­ness.  Etch areas must be the cor­rect color.  Cut lines must be cor­rect, and so on.  I finally refined the design to a for­mat that passes the upload gate­keeper and clicked through to get an esti­mate.  Given the cut­ting and etch­ing on the wooden ends, I expected them to be a lit­tle spendy, but they are reusable.  The really dis­heart­en­ing part was that the card­board filler was $1.95 in mate­r­ial and $49.30 in cut­ting.  The whole cat-scratcher would cost just over $90.  Ouch.

As Microsoft BASIC used to say: “Redo from start.”  Back to the draw­ing board.  I decided I would cut the card­board myself.  Between ship­ments I occa­sion­ally get and Kim’s busi­ness, we have a ton of card­board boxes lying around and I could spend some time and elbow grease with a box cut­ter.  This meant a rec­tan­gu­lar design because I was not going to sit around cut­ting wavy lines by hand.  I would have to buy the hard­ware (wingnuts and bolts) regard­less of how I man­u­fac­tured it, so went out to seek those from Home Depot.  While there, I got inspired by some ornate mould­ing.  I decided to base the design around nicely stained mould­ing and not laser-cut pieces.  This also allowed me to make my design a lit­tle longer than the orig­i­nal and, at just over $2/ft, was way more eco­nom­i­cal.  Laser cut­ters, you are cool, but you are not for this project.

Hardware

I looked around at the selec­tion of bolts of a usable length and could not find one I liked.  At that size, you are mainly look­ing at hex bolts and car­riage bolts.  I didn’t like the aes­thetic of the hex bolts.  The car­riage bolts looked a lit­tle bet­ter, but I didn’t like the way you have to make an extra cutout for the extra thick square part of the shaft near the head.  I decided to just go with a threaded rod.  I could cut that down to any size with my favorite Dremel attach­ment: the car­bon rotary cut­ter.  It had the added bonus of look­ing more sym­met­ric.

Required hard­ware: ¼” threaded rod, four wingnuts, four wash­ers

Cut And Finish The Moulding

I started with the afore-linked mould­ing and sliced it down to an arbi­trary length based less on mea­sure­ment and more on hav­ing four com­plete pat­terns on each piece.  I threw away a few cen­time­ters at one end as scrap because the board started mid-pattern.  I also used this time to visu­al­ize where the holes (and con­se­quently, the wash­ers and wingnuts) would sit within the pat­tern.

Careful square cuts in a mitre box
Two uni­form pieces plus some scrap

The edges were rough and needed some sand­ing.  As I recall, I started with some 80-grid sand­pa­per and grad­u­ated up to 220-grit.

These rough cuts need sand­ing

Although nobody would ever see the back, I thought I would sand out the stip­ples that, pre­sum­ably, were left by the man­u­fac­tur­ing process.  It would make the back look a lot bet­ter, espe­cially after stain­ing.

Before (left) and after (right) sand­ing out the stip­ples

I found it ter­ri­bly use­ful to do this with a disc sander ver­sus sand­ing by hand.  I also found out, the hard way, that hav­ing a piece of butcher paper between the wood and my work sur­face would pre­vent the wood from pick­ing up dirt and old paint from the table.  While sand­ing the back, the face picked up a bit of old green paint that I had to care­fully sand out.

Working on a sheet of paper

I then drilled and filed out the holes.  The drill bit was just a size up from ¼” to allow the threaded rods to eas­ily slip in.  This is one step where I may have to do a bit more research on the best way to per­form this next time — if there is a next time.  Quite often, when I drill a hole and do not want to leave splin­ters around it, I will put a piece of mask­ing tape on each side of the wood.  This method did not work so well in this instance.  I am not sure if it is because of the shape of the face, the den­sity of the wood, the speed of the drill (I tried a cou­ple dif­fer­ent speeds), or the sharp­ness of the bit.  At any rate, I got a few more splin­ters than I would have liked.  I both cleaned up the holes and per­formed a bit of surgery on the splin­ters with a small file.  At any rate, any splinter-induced imper­fec­tions would later get cov­ered over by a washer.

I then put a few coats of stain on them.  This took a lot longer than expected because of the freez­ing tem­per­a­tures we had that week.

First coat, dry­ing

The Cardboard

The next step was to cut the card­board.  I basi­cally just took a cut­ting mat and a box cut­ter and attacked the card­board.  By this time, the wooden ends were dry, so I used them directly as tem­plates.  Since the boxes had slots in them for the top/bottom flaps, I had to work around that.  I used mask­ing tape, on both sides, being sure to keep it a few mil­lime­ters from the edge so it was not stick­ing out or vis­i­ble when the card­board gets sand­wiched.  I also pushed the cut flaps close together when tap­ing so that there was no gap between pieces.  I also made sure to pull off any left­over pack­ing tape because I wanted to guar­an­tee the exposed cut ends were just card­board — no mask­ing tape, no plas­tic pack­ing tape, no ship­ping labels.

Keep the tape away from the cut lines
Push together any gaps

This left me with a lot of card­board (this is three small-to-mid sized boxes worth), cut to the right size.  If I were to do it again, I prob­a­bly would have cut the holes for the threaded rods as I went instead of wait­ing to drill them at the end.  I could have just marked through the wooden piece’s hole with a pen­cil, then used the box cut­ter to make an over­sized square or dia­mond hole.  The hole does not need to be all that accu­rate or even round  because it gets sand­wiched together and held by com­pres­sion.

I rearranged the card­board strips so that I did not have too many masking-tape-gap ones or ones with folds next to each other — for bet­ter looks and struc­tural integrity.  Finally, I held every­thing (loosely!) with clamps and drilled some holes for the rods to get through.  This took sev­eral tries because my drill bit was not long enough to go from one end to the other.  I had to drill in one hole, then go around to the match­ing hole on the other side.  Since I was doing this by hand, the holes were not per­fectly straight and did not quite match up.  It took a few attempts to get a com­plete hole from one board to the other.

Finishing Touches

I was then down to assem­bling and trim­ming the hard­ware.  I put the threaded rod through one end, attached wingnuts and wash­ers, trimmed it, and then did the same for the other end.  I also made sure to deburr any rough cuts in the metal.

One rod cut
The fin­ished prod­uct

Cat Approval

Leave out for the cats, throw on a lit­tle cat­nip if you like, and observe the results.

Cat approval: suc­cess!

Posted in: Projects

batcat

My Pet Bat

Life has been busy the last cou­ple of months and my lack of posts on this blog rein­forces that.  In early January, I got a MakerBot, which has been a bit of a DIY adven­ture — the sort of adven­ture that’s maybe not so fun and a lit­tle scary in places, but with time and dis­tance, you look back upon it and laugh.  Actually, things are pretty good on the MakerBot front and I expect to have a more detailed post on that in the not-too-distant future.

The MakerBot has kept me busy (assem­bling, print­ing, fix­ing, mod­el­ing).  There were a cou­ple of mod­ern works of fic­tion that hooked me and ate up a bunch of spare time (The Machine of Death and The Girl Who Played With Fire) as well as some non­fic­tion for work and fun.  Work has kept me busy, too.  All this added up to a per­ceived lack of time for blog posts.  I think I really did have the time, just no moti­va­tion.

I have good ideas for the next few posts per­co­lat­ing, but until then I leave you with what is prob­a­bly the eas­i­est post pos­si­ble to pro­duce: freaky pic­tures of my cat.


(also as a video)

Posted in: Dear Diary Pictures