Printrbot jr assembly part 2

Day two of the build I spent more time, still had a lot of fun but also experienced the first issues, that still haven’t been resolved…. I also did a first test render of a time-lapse movie of the whole build, lots of fun! May or may not be published and posted here. :-)

Early on day two I realized what I first looked like a tiny little wrench (but ignored for a while since I also thought it might be a weird new component for the printer) actually was a little wrench! Cute and quite helpful.

Tiny printrbot LC wrench!

Tiny printrbot LC wrench!

Started before the kid went to sleep so I could pound the Z rods in. They were a bit tricky. I started out by sanding the holes at the top to even get them through, but on the bottom holes I used a rubber mallet with support under the bottom. Worked fine, but made a lot of noise.

Had to do a lot of sanding of the holes for the X/bed hinge rod as well. They were extremely tight. Would have been much easier to do before the base was mounted but taking it apart again after forcing the Z rods in was not an option. I took the screws off the X stepper to move it a few millimeters away so it would be a little bit easier to avoid damaging it. As a general rule from this point on I made sure to sand all of the holes for rods before assembling them.

Z rods and X/bed hinge finally in place!

Z rods and X/bed hinge finally in place!

X rods installed.

X rods installed.

It was a little tricky to tighten the X belt, felt like I got it pretty tight but after having carefully zip tied it I’m not sure if it’s good enough.

One of the zip ties on the X axis belt.

One of the zip ties on the X axis belt.

Next up was the Z coupler for the Z screw. I had already noted that the groove in one of the parts looked a bit weird, but didn’t realize how bad it would be. I first had an insane amount of wobble, it was really crooked. For now I’ve used some pieces of zip tie plastics to shim it but there’s still plenty of Z wobble. Have been googling and found some interesting options on ebay (aluminium couplers) but there’s also printable options. Let’s just hope I can get the wobble down to the bare minimum needed to get prints done.

The bad Z coupler.

The bad Z coupler.

The Y/Z sandwich was next. Lots of fun, had to sand a little bit to get the linear bearings to fit in the middle piece. Otherwise pretty easy to assemble actually.

The nut trap for the Z axis is mounted using very long screws, lots of fun if you're using a regular screwdriver!

The nut trap for the Z axis is mounted using very long screws, lots of fun if you’re using a regular screwdriver!

Y/Z sandwich done!

Time to get the ends of the Y axis together, nice feeling to see the pile of LC parts quickly shrinking to nothing. Less fun was the missing screws. I’m out of longer screws now, only a 1.75 inch left and that’s way too long. Needed one more 0.75 and one of the elusive 1 inch screws. So the back end of the Z axis is currently held together with one single screw. It feels surprisingly solid though. But I’m going to get an ISO M screw with some nuts to least have one that I can adjust the end stop with. It’s next to impossible to buy non-metric screws here, I’ve tried before to get screws for a server rack mount and they guy we sent to the local shops was laughed at for even asking…

The Y end that’s missing two screws…

The front Y end, aka the extruder mount.

Tightening the Y belt felt a bit easier than the X belt, perhaps because I had a tiny bit of experience. :-) I hope it’s tight enough, if it isn’t I’ll look at printed belt tightening options sooner rather than later!

One of the zip ties holding the Y belt.

One of the zip ties holding the Y belt.

Y assembly done! Belt pretty tight, will be interesting to see if it's tight enough.

Y assembly done! Belt pretty tight, will be interesting to see if it’s tight enough.

It was pretty to easy to get the big sandwich onto the Z rods, also adjusted the Z endstop, will add another nut for it to get less wobble. Saw that Brook had two in his video, only one in the instructions though. This looks nice as well.

Very happy with the progress during day 2!

Progress after day 2.

Progress after day 2.

So what’s left to do now is assembling the extruder/hot end, mounting it on the printer, make the cabling a bit more sane and finally get the printrboard in there. The latter looks a bit tricky actually, there’s a lot of cables and very little room. Would have been nice with some spare connectors and simply cut the cables where appropriate to get custom lengths instead.

Update: Part 1 is available here and Part 3 here.

Printrbot jr assembly part 1

Finally got some time to work on assembling the actual printer. Started out with going through the LC parts to check if they were all there. Also snapped some photos of other components:

All LC parts



Screws, nuts, etc. Nicely packed in sealed plastic bag.


Rods, note the two shorter ones are taped and tagged that they’re for the X carriage.

Two big and two small stepper motors. There’s a sticker on the printed copy of the BOM about the uses of the two different sizes, see below.


The stepper motors with the power supply in the background.

The herringbone gears seem to mesh pretty well even though they don’t look very pretty in some places, but I’m probably replacing them with normal gears eventually, when the printer is up and running that is. Or perhaps do what I’ve seen others do and order them from Shapeways instead.


Herringbone gears and the rest of the extruder kit.

Saw someone else the other day that also had JR written on a couple of places on the printrboard. My guess is that they printrbot guys have configured it with the proper dimensions? Can’t find the thread right now.


printrboard from above


printrboard from the side

Note that the printed copies of the BOM and the laser cut part numbers are newer than the ones on the web site!


printr bot lc part numbers


printrbot jr updated BOM

It’s a bit difficult and slightly scary at first to snap off the remaining small tabs of plywood that connects the laser cut pieces. So far I’ve only managed to damage one of the pieces that’s not used, a couple of layers of plywood broke off. Would probably have been easy to fix with some wood glue though. After breaking them apart I use some small files to sand down the protrusions. Only one piece so far had some damage already:

Slightly damaged LC part, not a problem though.

Slightly damaged LC part, not a problem though.

The instructions are actually pretty good, make sure to use the new updated ones though, but it looks like they’re now the default. Videos are good, I’ve watched them a while back as I said in an earlier post but now I’m rewatching them at night in bed, and then I use the instructions when I actually do the assembly.

Started off with the base, as instructed. There is a lot of creaking and some force needed, but as Brook says in the video that just feels good. Had to leave the screws very loose to retain some flexibility for when the first part of the lid went in, it was a bit tricky.

Pieces for the base.

Pieces for the base.

Base done!

Base done!

Z endstop in place!

Z endstop in place!

Z stepper in place.

Z stepper in place.

Locking mechanism for the foldable bed.

Locking mechanism for the foldable bed, test mount to check if it fits.

X carriage with endstop.

X carriage with endstop.

It’s a little tricky to get this sandwich screwed together, but there’s a good tip in the instructions.

X carriage again, with stepper, pulley, bearings and belt.

X carriage again, with stepper, pulley, bearings and belt added.

A weird thing with the instructions for the ends of the print platform is the screw lengths, the single screw that’s supposed to have a nylock on it is too long, I don’t have any 1″ screws at all. Only 0.5, 0.75, 1.25 and 1.75 if I remember correctly (used my digital caliper since I suck at imperial measurements). We’ll see how things work out later on, worst case I’ll be missing screws of the appropriate lengths later and I guess I might have to saw of a bit of the one sticking out of the nylock nut now. I’m guessing it’s there to press on the X endstop switch? Need to check if there’s any M screws and nuts that is a good fit instead of the 6-32 (!) screws and nuts.

printrbot bed mount with leveling springs.

printrbot bed mount with leveling springs.

Progress so far.

Progress so far.

Update: Part 2 is available here and Part 3 here.

Printrbot Power Tower assembly

After assembling the birch spool I upped the difficulty level slightly and decided to take on the Power Tower. Still easy compared to the actual printer, but allows you to start getting a feel for how much you should tighten the screws.

Power Tower bag

All of the Power Tower laser cut parts, screws, nuts, bearings etc came in a sealed plastic bag. Note the fan cutout in one of the sides, it doesn’t seem to be there in the instructions, but very nice if you change to a more powerful power supply that either has a the fan on the bottom or has two fans. After opening the bag I put everything in a nice little pile.


Power Tower parts

And then I sorted the screws, and figured out which had which length (I love the metric system).


Power Tower screws and nuts

As you can see on the picture above there’s a bunch of pieces of wood that the laser hasn’t fully succeeded in cutting all the way through. With the help of a sharp knife and some force I got them out, you can see them below:


Power Tower LC leftovers

After that it was pretty easy to follow the guide and assemble the tower. The only real problem I had was that the rear cutout that fits onto the back of the power supply didn’t quite fit. I used a file to make some more room for the power socket plastic frame, followed by a bit of force. Paused to take a picture when I was about halfway done, before the spacers and bearings on the top half for the spool:


Power Tower halfway

As you can see above I also got some zip ties and tried to make the cabling look a little bit nicer. Getting rid of the unused connectors would be nice… Didn’t take long to finish up, a good tip is to make sure the screws near the top aren’t tightened, otherwise it’s next to impossible to get the spacer plywood pieces in there.


Power Tower done!

Printrbot jr kit has arrived

A while ago I got really intrigued by FDM 3D printers. The reasonably priced ones are  quite crude still, showing their reprap roots. Very few if any options exists if you just want to plug & print and they’re still pretty expensive considering what you get. After finding the kickstarter project for the Printrbot jr I started to think it might be a good compromise. It’s fairly cheap but still pretty capable and easy to hack/modify.

When the kickstarter project that I backed on impulse failed I continued reading a lot, viewed the assembly videos, read Make Magazine’s guide and agonized a bit. Then I finally ordered the Jr kit with some extra accessories on January 2nd. It was shipped on the 25th and finally got to Sweden with me picking it up the same day on February 4th. In addition to the Jr kit I also purchased the Printrbot Power Tower, a birch filament spool and an additional 1kg spool of natural PLA filament.

Unboxed printrbot contents

Unboxed printrbot contents

As you can see in the picture I got the Jr version with an ATX power supply, either because they’re only shipping the newer version with a small 12V adapter in the US or because I ordered the Power Tower. I might want to add a heated bed later on for ABS plastics so I’m happy with the ATX power supply though. Very nice that the 1kg of PLA filament came on a printrbot birch spool.

After a rough check that all of the parts seemed to be there I decided to start with the birch spool and then put the 1lb roll of filament that was included in the kit on it. Putting together the spool sort of eases you into the business of laser cut plywood mounted together with weird (to me) imperial screws and nuts. Getting the filament onto the spool wasn’t as easy as you would think, got the tip later on from a friend that heating it up a little bit would have helped (only to 30 degrees C). It did not act very friendly at all at noral room temperature.. The one to the right below is the one I put together.

Printrbot birch spools

Printrbot birch spools

I plan to keep adding posts detailing my progress! Next up is the power tower!

Wayfinder open sourced!

I got involved in a final project at Wayfinder Systems after we got permission to release a majority of our source code as open source. We’ve spent the last months cleaning up code and writing documentation and now it has finally been released! Have a look at the blog post over on the Wayfinder OSS site for more details. In the released code you will find our location based server platform and map & navigation clients for the major mobile platforms.
Vodafone has also published a press release!

I spent most of my time cleaning up and documenting the operations aspect of the server, and this includes releasing a lot of tools and scripts that we used for operating the Wayfinder server clusters but are generic tools. The two most interesting ones are WFConf; a minimal but still powerful Configuration Management tool (but I still recommend Puppet if you want to start using a CM tool) and a web based network kickstart file generator.  WFConf is documented here, and if you’re interested go ahead and look at it in the repository here. There you’ll find the less documented kickstart files as well and there is some sparse documentation you can have a look at.  The kickstart stuff is quite easy to use. You start out with a normal kickstart file and then you cut out the sections you need to vary across different servers and put the snippets  in separate files. You then create new nippets for different configurations, typically things like root passwords, disk partitioning, the post section etc. When you PXE boot your server the kickstart file is fetched from a Perl CGI which looks in a config file to determine which snippets to include for this particular server and pastes them into a complete file which is returned. In the config file you setup defaults and then specify the individual snippet configuration based on the ethernet address of the server. Here’s what it might look like:

%ks_ethers = (
   # defaults
   'default' => {
      'grubfix'      => 'nop',
      'rootpw'       => 'example',
      'partitioning' => 'one_disk_sda',
   # mgmt1
   '00:aa:bb:cc:dd:ee'   => {
      'partitioning' => 'md_raid1_sda_sdb',
      'grubfix'      => 'md_raid1_sda_sdb',
   # node1
   '00:aa:bb:cc:dd:ef'   => {
   # node2
   '00:aa:bb:cc:dd:f0'   => {

Combine this with a configuration management tool that setups all of your services and you can have a server with a specific configuration and role re-installed and ready to run in less than 10 minutes

Time to sign up for Scott Kelby’s Worldwide Photowalk again

I’ve signed up for the 3rd annual Worldwide Photowalk in nearby Malmo. It’s the third time for both me and the actual event! If you want to learn more about what a photowalk is have a look at the Worldwide Photowalk site. Hopefully we’ll get to walk in good weather conditions, the first year was pretty awful. I participated by mostly trying to document the walk itself and unlike the rest of the participants I didn’t dare to use my DSLR in the rain. Here’s the short video I put together:

Last year the weather was much nicer and you can see my results by clicking on this photo:


Convenient interactive renaming in zsh

While risking turning this into the renaming files blog I just used another one of my favorite functions that I’ve named iren and realized it could be worth sharing as well. This one is really simple to put together when using zsh. It will allow you to type iren file1 file2 ... and for each file name specified you will get to interactively edit the file name using the normal line editing features in zsh. When you’re done you press enter and the file is renamed/moved. If you haven’t tried it before I can really recommend zsh, it used to be the best shell by far, although bash has caught up on many areas. iren uses the built-in zsh function vared that can be used to interactively edit any environment variable. Here’s the iren function, put it in your .zshrc file:

function iren ()
        while [ "$1" != "" ]
                vared dest
                if [ "$source" != "$dest" ]
                        mv "$source" "$dest"