How to export to a CNC from KiCAD and Fab Mods

So, while working on a new board design I decided to learn KiCAD a bit more. I’ve detailed the board design and files in an upcoming post so keep an eye out for that one. Here’s I’m just documenting the process to make a board by exporting the design from KicAD and generating cut files in Fab Mods.

I came across a LOT of different methods looking at other Fab Academy students. Some had weird scaling issues or other problems.  I’m showing how to use two different methods for producing and SVG file.  Export–>SVG and plot as an SVG.  I also show two ways of generating cut files, whether you are making Gcode for a generic CNC or you’re making an RML file for a Roland SRM-20.  Note, I’m using KiCAD 5.4 on Windows 10 here.

In the examples below I’m using Quintin’s SAMD11C board found here.

 

Method 1: Export SVG directly from KiCAD to Mods

 

Method 2: Export an SVG using the “plot” function then convert to PNG for Mods:

 

Caveats and other important details:

I have rebuilt my shapeoko V1 as a PCB mill and so the difference between this and an SRM -20 Roland PCB mill is just what program you select from mods when you are creating the cut file.

If you aren’t running the websocket for fab Mods, you’ll need to replace the “websocket” module of the Roland programs with a “file save” as shown below:

 

Once you’ve exported the file you can follow this procedure on a Roland or other CNC machine to mill the board.

 

Once you populate the board, you can program this particular one with an Atmel ICE. Here’s the connections for that:

Connect up the atmel ICE programmer to the SAMD board. I used figure 3-8 from the atmel ice manual to figure out the pinout because we are using the Serial-Wire debug (SWD) pinout.

Pin 1 is Target Voltage (Vcc), pin 2 is SWDIO, pin 3 is GND, and pin 4 is SWDCLK. Pin 10 (Reset) is the back corner you can’t see.

Milling a Dollhouse Design from Etsy

For our daughter’s birthday, we noticed how much she seems to enjoy dollhouses so we decided to build one for her. She has plenty of dolls she could use with one, by she doesn’t have the house itself. We have always made her gifts (Last year was a ukulele — yea, yea, we know she’s way too young for it yet… give it time) and we really didn’t want to buy a dollhouse made out of a whole barrel’s worth of oil.  Since I’m no CAD star, we looked online for good plans to use.

We came across this Etsy seller and in particular this design. For less than $15 we got the plans which can be used for either a router or a laser cutter and either 5mm or 6mm plywood. For $20-30 we got the flattest and prettiest sheet of quarter-inch plywood from home depot and had it cut in 2′ x 4’ sections to fit in my car and my machine.

At the bottom of this article I have a bullet checklist with a quick reference of all my tips for this project.

My machine is the Xcarve which has the cutting area of about 32”x 31” and the dollhouse plans are HUGE in comparison, so I have to make separate panels for each piece and can’t cut all in one go.  I found that the Xcarve is nowhere as good as a shopbot in terms of precision and rigidity so I ended up doing a lot of small test cuts rather than large cuts anyway.

The first hurdle I had was that while the plans I bought came with 4 different file formats, (Abode Illustrator, AutoCAD dxf, CorelDraw, and SVG) When I imported the SVG into Easel, it garbled some parts. Some parts were solid shapes and I could not simply select to cut the outline of the shape. The problem was that Easel likes to have “closed” so the lines used for decoration (like the shingles) wouldn’t cut.

I’ve only cut a couple of projects with Easel which I find much simpler to use than other CAM/Gcode-sending software, but haven’t had tons of luck with external CAM. This led me to hunt for a better option. I had seen online that MakerCAM could do open vectors, but I found it tedious.

I ended up using Carbide Create (originally for the Shapeoko 3) which is adequate for the most part.

The workflow is as follows:

Open SVG in Carbide Create –> build toolpaths –> export Gcode file –> import gcode into Easel –>Send to machine.

If you use another machine or controller software, just replace the last 2 steps with your software.

I found the default feeds and speeds in Easel were way too conservative.  For each toolpath, I tested on the smallest part of the dollhouse, the windows; which I needed a bunch of anyway. Playing with the SVG showed that the dollhouse design had dogbones in the interior corners (as it should) and those were approximately 1/8” in diameter which gave me the size endmill I needed to use.

You can check out this official series of videos for basics in Carbide Create.

The order you cut the line in the design actually matters. You want to cut all decorative engraving first, then interior cuts, and finally the outlines. Select all the design elements you want engraved (if your design has any) and create a toolpath for them. In my case all the open shapes in my SVG file (which Carbide Crete shows as pink) are what I want to engrave. Holding Ctrl, I click each line I want, then click the “Contour” button near the top left of the screen.  This opens the “toolpaths” section which you can always get back to by clicking the green “toolpaths” button at the top of the screen. I select a 1/8” (0.125”) flat endmill for my tool. In my case, I created my own tool to play around with it. Then to override the incredibly conservative default feed rates, uncheck “Set speeds and feed automatically” so you can type in the boxes below.

Since I’m using a 0.125” endmill, the typical stepover and stepdown rule of thumb is these should be no more than 0.5*endmill width which in my case is 0.056” each for the maximum speed. I am using a 4-flute 1/8” bit at 10,000RPM, so I should be able to fly through these cuts. The default feedrate is 12.5 inches per minute (IPM). Easel’s default for a single-flute 1/8” is 40IPM.   Since my bit as 4 times as many cutting edges, it’s able to remove material about 4 times as fast as a single flute  but I set the feed rate to 40IPM. The 10,000RPM is too fast for what I’m trying to do, but that’s as slow as my router will go.

Override Defaults

The next step is to set up the type of cut, max depth, and if you want to add tabs. Since these are superficial cuts, I want to just have the center of my endmill follow the path of the line so I use “no offset”. Since I’m starting my bit at the top of the material, I leave “Startdepth” to 0.000in. I only want an engraving so I use 0.06 inches depth. My material’s thickness is 0.21in so this should be a nice relief. It is also deep enough to not have issues with my unlevel machine. As long as I get the impression of the lines  it is OK if they aren’t all the exact same depth, though this is something I should fix in the future. There is no need for tabs on this cutting path so I ignored that option for now.

At this point you can try to see the simulation of the cut, but as of the version I am using the simulation is not very accurate as shown in the full simulation of the part below. Several lines are completely missing (which actually did cut just fine) and the engraved contours have random jagged areas (which don’t appear in the real cut). I recommend avoiding the simulation in this software at this time.

image

I saved the engraved cuts as “siding” which you can see highlighted in red below.

details1

The next set of cuts are all the interior cuts such as the doorway and the slots. Holding Ctrl, click each item you want, then set up a cut for the interior (the default selection). Don’t forget to change the stepover and feedrate, otherwise it’ll take you many times longer to finish the cut. For the larger areas (not the slots) I added tabs. Tabs on these pieces are areas that don’t cut completely through so the interior part doesn’t wobble around and break stuff when it is cut out. To add tabs, in the toolpath simply click “Edit tabs” and then click on your shape where you want tabs. Tabs appear on your drawing as a little box with an ‘X’ in it. I recommend only having a few tabs (the fewer you have to clean up later) and placing them strategically. For instance, due to the unlevel-ness of my machine, sometimes my tabs are only as thick as the bottom facing of the plywood which is sometimes not strong enough to function as expected. This also depended on the grain direction and direction of the cut. For instance, the tab on the left side of the doorway broke because the grain of the facing ply was vertical and so was the direction of the cut. I also tweaked the tab size to make it hold better and easier to cut when the cut finishes. image

I saved this as “InnerCuts” which is shown in red below:

interior cuts

Finally I made the toolpaths for the exterior cuts. I used all the same depth and stepover settings as with the inner cuts. I added some tabs and this toolpath as “outside cuts.” I honestly changed up the cutting speed to up to about 55in/minute and didn’t really see any detrimental results. You can play with these settings to see what works best for your job and set up.

Once all the toolpaths are set up they need to be exported as g-code. While you can export them all as one file, and they would execute top to bottom, I strongly discourage this. Export each one separately because if something happens and you need to recut (maybe you didn’t go deep enough on the first try, etc.) you can always go back to 0,0,0 on your machine and make tweaks to the starting position as needed and try again.

I imported the gcode files into Easel.com to send to my xcarve. You can import gcode by going to File—> Import gcode.

image

I loaded the three files in the same order as I had created them. Engrave, then interior cuts, then exterior cuts. Each one is automatically loaded into its own “workpiece” as shown at the bottom of the screen. In this example, I actually only did the bottom wall because I forgot to save screenshots from the workflow above. Just note that whatever you set up in your toolpath should be shown in Easel.

image

Midway through the project, Inventables added the easily-accessible Jog feature to Easel which I found to be incredibly helpful. Since then, there are lots of new features that have been added.

I loaded the wood onto my machine. I was using 2’ft x 4ft sheets of 1/4″in Sande ply. We actually bought two 4ft. by 8ft sheets at the orange big box hardware shop and had them cut it to the smaller size for us to fit in the car.

The xcarve can’t cut the full 4ft length, but I loaded it into the machine without shortening it. This is because once I cut a full-size panel, I then flipped the plywood around and cut another piece on the previously unreachable area.

To mount the plywood, I use the same method I used for manually planning guitar blanks in the past with great success. After laying down the plywood on the machine with the bowed par facing the table (bowed edges flexing upward)and getting it relatively straight and in line with the X and Y motion of the router I laid down a strip of 2” masking tape on my spoilboard halfway under the wood running the length of the board. A tip here is don’t align to your rails or you’ll have a bad time.

After realigning the plywood, I go back and glue the edge of the board to the tape using a high-temp hot glue. To flatten out and bowing the in wood I use my free hand to apply pressure an hold until the glue is hardened, or you can set some clean heady books on it. You don’t really want the glue under the wood, just along the edges. Since we laid the bowed part of the wood into the table, that’ll make it easier to not have a ”bubble” in the middle of our wood that would mess up any cut depth there.

Throw your 1/8” downcut endmill into the collet and you’re about ready to cut. You want to use a downcut endmill because it if there is any bow or warping to the wood, as it cuts the force of the flutes will put downward to help flatten the wood. This also leaves a much nicer finish on the top of the wood. Sadly, I didn’t find all this out until after I made all my cuts and as you can see below, had to manually use a razor blade on all edges to clean them up.

Once the glue is set, I turn on the machine and click “Carve” in Easel. I can then jog the router to the bottom left corner just to the interior of the wood by about the size of my bit on each axis. This will give me a margin of error incase I didn’t align my tape very well.

After zeroing X, Y, and Z, I jog the z down slowly until the bit presses about 0.1” into the wood. This will help me realign if I need to hit the E-stop and lose my home coordinates.

I quickly turn the router on and off to make a small indention here. If something catastrophic happens and I hit the E-stop or lose power and my machine forgets its location, I can manually adjust my X and Y locations until the bit  fits snuggly into this divot and I know I’m pretty close to my original zeros. I zero the X and Y axes at this spot. Lift the bit and move over the wood just next to this divot (I usually move X to the right 1”) and bring the Z axis to touch the top of the wood. I actually put a little pressure on the wood by a couple 0.001” movements.

Part of the workflow in Easel allows you to zero the Z axis by itself after you confirm your location and material thickness. I zero the Z axis at this point. Then in the Job menu, I bring the bit up a touch and move back to X=0 (move X back to the left 1”). Then you are ready to cut.

It’s loud, so wear ear protection. Also wear a dustmask with the appropriate particulate filters. I have a dust boot on my machine, so I set that up. The vacuums I have for my dust boot consist of a household vacuum we’ve had for like 15years that recently lost a wheel and a tiny shop vac. Neither of these were designed to run for hours on end in 90+ degree weather (in the garage with the door open in the middle of NC summer). They both overheat during the cuts so I cycle them out as often as I can. I also run my air filter the whole time and for a few house after I am finished. You might think that with the door of the garage opened you wouldn’t need this but you’d be wrong.

While cutting, if something isn’t right, it is always best to hit the Stop button unless there’s a serious emergency (like someone getting hurt). If you hit the normal stop button (wither in Easel or on the Xcontroller) the Xcarve will finish its current cut, raise the bit to the safe height and bring it back to X0,Y0, Z(safe Height). This way, you can make simple modifications to either the code and try again without losing your position. If you hit the E-stop button, the machine completely cuts off and disconnects from the computer. This will lose your current position.  You’ll have to try tot manually set up your X, Y, Z which is never quite correct. That’s why we made that divot in the beginning though. Just in case you hit E-stop you can jog the bit back into that divot, raise the bit, move over and set the Z height again just as before and you’ll be kinda close.

Once all 3 cuts are finished, your part is still stuck in the workpiece because of the tabs. The easiest way to remove the tabs is to use a chisel. Place the flat side of the chisel against the part you’d like to keep and give it a stern whack with a mallet or hammer. This should break the tab and leave you with a relatively clean edge.

To remove your stock material from the table, simply pull upward near the end of one edge and the hot glue should peel off the tape. You can reuse this tape a few times before having to reposition it.

Once I had cut all the dollhouse parts, I cleaned up the edges with a box cutter and razor blades and sanded everything with 220 grit sand paper  on my orbital sander to flatten it a bit. The 1/4” ply is slightly thicker than the metric 5mm of the design do for the tabs to fie correctly into the slots, I had to make sure to sand these a bit more. It’s ok if they fit a little loose too because when you add shellac it thickens the piece, then you can put on the twist-knobs to tighten the tabs to the faces of the part with the slot.  This really is a genius design and works well if you sand it enough.

After the initial fit, I went back and had to sharpen the interior angles of all the tabs so they’d fit flush with the slots. Without this the design would never work.

I used my box cutter and some tiny files for this. You don’t want any overhangs because when you seal it in the next step, anything that is a soft burr of wood becomes a tiny razor blade or needle when the sealant dries on it.

Take everything outside and shellac it because Sande Ply smells horrible!  I think it is formaldehyde in the glue. I sat all the pieces out in the sun for a couple of days (each side getting 1 full day of sun) in the 90+ degree heat which drove off the majority of the stank. I needed to seal it though to prevent exposing my kid to VOCs. Shellac is a natural ingredient made from bug poop dissolved in ethyl alcohol. It is FDA approved (used to coat pills for decades) and often used for baby cribs. Seemed like a great option. I had bought a half-pint of shellac and did it by hand which took forever and didn’t look great. I recommend you buy spray cans of it for fast even coats. Three or more light coats work best for sealing. Make sure to sand with 200 grit paper between each sanding and let it dry for a couple hours between coats. The result slightly darkens the wood, smooths the surface finish, and most importantly, completely seals all the pores of the wood so no chemicals will get in or out of it.

We had to sand the tabs a bit more before it fit back together, and not all the toggles cinched without breaking the tabs. No big deal, that’s why Ii have glue.

This project took quite a while to complete, mainly because of the finishing steps. It took a full 3 days of figuring out my workflow and cutting on the machine (I messed up a few times too in the learning process of course), another couple of weeks for clean up and sealing as I only worked on it on the weekends.

The final result: My daughter absolutely love it! She immediately began playing with it as soon as I brought it in the house. It isn’t the most ornate, or even well-built but I’m proud of it.

Ok, so here’s the cheatsheet for this project:

  • Get plans for the design. Either make it yourself (which could easily be several posts in itself) or buy them.
  • Carbide Create is a great offline tool for generating toolpaths.
    • Make sure to change the step over and depth EVERY TIME you create a toolpath unless you are immortal and time is meaningless to you.
    • Make sure to check the the start depth and ending depth before exporting the gcode
    • Change tabs to make sense. I did 0.3” thick and 0.118 tall since my stock material bowed a bit and I was using a 1/4” chisel.
    • Export each cut separately
  • Import gcode into Easel in this order: Engrave –> inside –> outside cuts.
  • Lay down wood on work area with the bowed part down (edged bending upward) and align 2” masking tape just under the edges
  • Use high temp hot glue to secure edges of wood to tape using weight to keep it flat if needed
  • Use a downcut endmill for best results and to help prevent the wood pulling upward in the flutes.
  • Move router to bottom left corner where bit is just fully inside the edges of the wood and jog Z down a bit. Turn on the router and adjust Z until you create a divot in the wood. This will serve as your way to recapture the 0,0 of the job if E-stop or power failure.
  • Zero X and Y axes to this point.
  • Move Z up and move X—>1” and use Easel’s Carve workflow to set the height of the material (which Zeros the Z axis)
  • Move the X back over the divot
  • Carve the piece.
  • Rinse and repeat with each cut
  • When finished, use a chisel with the flat side on the part you want to keep to remove tabs.
  • Sand with an orbital sander with 200 grit to remove all the burrs and sharp edges.
  • May need to use razor blades or hand-sand to get some tight spots
  • Go ahead and make interior cuts of the tabs square for a better fitment
  • Sand tabs more than you think you should. They would fit loosely in the slots and the toggles should turn easily when you put the house together.
  • Let wood sit in hot sun for a day on each side with ventilation underneath (I have a slatted patio table) to remove the formaldehyde stank.
  • Spray with shellac (don’t brush it on unless you have to for tiny detailed spots), let dry a couple hours, sand with 200 grit.
  • Rinse and repeat until all parts are sealed well.
  • Put it together and enjoy.

Basic setup for all Raspberrypi projects

This is a starting point that I do on every one of my raspberry pi projects. You can branch off from this point to any number of projects. I used to like a screen and keyboard/mouse interface, but this is how to set up a headless rpi that you only control over the network. it is much easier than it sounds.

Hardware:

  • Raaspberrypi startup kit with power cable and SD card.
  • Computer (I have windows 10 but there are guides out there for mac and linux as well)
  • Wireless network to connect to
  • Maybe a camera to format the SD card?

Software Tools required :

  • SD card formatter (I use a DLSR camera because sometimes even this tool won’t format the cards right)
  • Balena etcher to burn the raspberryPiOS to the SD card

Firstly, I downloaded and installed the latest raspberrypiOS Lite to an SD card. Once it was installed, I reinserted the SD card into my laptop and created a wpa_supplicant.conf file in the partition I was able to open in windows (one will be openable, the other won’t be). This file sets up your Wifi settings so you can control the pi remotely instead of trying to find the right HDMI or component cable an display and connecting a keyboard and mouse to it.  I can simply ssh into the Rpi and run the scripts I need. This may sound intimidating, but it isn’t too hard at all.

Open a text editor (NOT word or notepad, download something like Sublime3 or notepad++) and create a new file names wpa_supplicant.conf. Paste the following and make sure to enter your WIFI’s credentials and keep the quotation marks.

country=US
update_config=1
ctrl_interface=/var/run/wpa_supplicant

network={
scan_ssid=1
ssid="Put your networks SSID here"
psk="Put your networks password here"
}

That will get the pi on the network, next we need to be able to actually control the Rpi from another computer on the network. To do so, just create a blank file with no file extension named “ssh” in the same SD card partition as wpa_supplicant.conf.  That’s it. This empty file just tells the Rpi to turn on ssh, which allows you to connect and control it remotely.

Now you can insert SD card into Rpi and plug in power to boot up.

With my older Rpi3 I give it like 5 minutes depending on the OS. Then you can check to see if your Rpi is on the network.  Open the command window in windows (windows key, then type “cmd” then enter) and type

ping raspberrypi.local

You should see a response. If it times out, then give it a little more time to install the OS and try again. If you can’t ping it (communicate with it ) after 15 minutes after you booted t up (or 30min or longer sometimes for a pi Zero w) need to start from scratch because something went wrong in your wpa_supplicant file. Triple check that the file is not saved as “wpa-supplicant.conf” or “wpa_supplicant.conf.txt” For that last one you may need to “show file extensions” in window’s explorer.

I always used putty to ssh into linux machines from windows, but Windows 10 apparently has ssh built right in, so you can just click the windows icon and type “powershell” to open a command window, then enter

 ssh pi@raspberrypi.local

We’ll use powershell instead of the Cmd window to allow us to copy and paste stuff into the window easily.

The first time you do this, it’ll give you a warning that it “can’t verify the [raspberrypi], do you want to continue”  just type “yes” and hit enter. Then you will be asked for the password. Note that as you type, you will see no letters appear in the terminal. This is normal for password entry on linux machines. The default username is “pi” and default password is “raspberry”.  When you type it and hit enter you should see a green line that says “pi@raspberry” which means you are logged into the pi.

The first order of business is to change the default password. type the following:

passwd

Enter your new password and you’re set. Now you can go off doing whatever random things you want to use the Rpi for.

To copy and paste into the SSH window you may need copy as usual form a webpage then right-click into the powershell window (maybe do this twice if you hadn’t already selected the powershell window) and it’ll automatically paste it for you.

Static IP: Next I like to set up a static IP address for my Pi so I always know where it is. This also helps things like streaming a webcam for Octoprint since the address won’t change. Android phones won’t use the mDNS entry of “raspbeypi.local” so if you want to use your phone to control or view things on the pi you need to set a static ip. Do so by issuing the following command:

sudo nano /etc/dhcpcd.conf  #this opens nano command line text editor to the IP address file...

My pi is on wifi  so I’ll adjust the wlan0, but you can replace this with “eth0” if your pi is using ethernet.

interface wlan0
static ip_address=192.168.0.100/24    
static routers=192.168.0.254
static domain_name_servers=192.168.0.254 8.8.8.8

This way I know all my raspberrypi stuff is found at 192.168.0.100. I can just type that in for ssh, or into a browser if I’m running a server on it (like octoprint, hassio, mjpg streaming video, etc.

Remote Desktop: To make it easier to connect to the pi in the future and to remote into it and control it’s graphical desktop from any other computer (such as your desktop or laptop), you can set up your pi to allow VNC. First, in your ssh terminal, we need to enable VNC.

sudo raspi-config

Then use arrow keys to select “Interface Options”.  Select “VNC” and you’ll be prompted to enable VNC the server. Then you can exit Raspi-config. On your desktop/laptop/other computer you need to install a VNC viewer which will allow you to connect. Visit https://www.realvnc.com/en/connect/download/viewer/ and install it. You should then be able to connect via the IP address of the pi, login to it and have full access and control as if you controlling it with your keyboard, mouse and monitor.

 

Remote shutdown:

Next you need to know how to shutdown and restart your rpi safely. It is a computer after all and I can’t tell if  just unplugging power will corrupt the SD card, so a safe method of shutdown is required. I use a couple. There’s a script you can add to allow shutdown by connection one of the GPIO pins to ground. This is essentially what you do on a regular computer’s power button. You tell the computer you’d like it to shutdown so it will trigger the shutdown functions. Secondly, you might want the ability to shut down or restart via ssh.

sudo shutdown -h now

or

sudo poweroff

and a restart is

sudo reboot

I’ve added a plugin and scripts to my octoprint setup to do the GPIO and I can shutdown from the web interface.

 

Now if at any point you mess up and can no longer communicate with the pi (setting the wrong IP address, etc) simply format the SD card in windows or in a digital camera and try again.

I recommend once you get all your settings correct, you backup your Rpi OS periodically. There’s a script that you can use to copy a bootable filesystem to another (can even be smaller) SD card you plug into a USB card reader on the pi.

Ukulele Repair

imageA few months ago, Jess accidently stepped on one of the ukuleles neck and broke the neck in two. Here you can see the break. It broke at the splice that was already in the neck. The fretboard came off at that spot as well.  We had recently build a ukulele from a kit, so we knew what to do.

The first step was to glue the two pieces of the neck back together.  I cleaned up any badly-fitting sprigs of wood and mated the two pieces together dry to find the correct length. If it isn’t the correct length, then the fretboard won’t fit back correctly and the scale will be off.

 

image

Once I got the placement correct, I used Titebond II mixed with a little water to thin it out and used a paintbrush to apply a thin layer of glue to both sides of the break.  I clamped it with a mini cam clamp and left it for 24 hours to dry.

image

Once this was done, I attached the fretboard piece. Due to the way it broke, I had to file down a couple places before it would fit correctly. I used the same mix of glue and water as before to attach it.  I clamped it with two large 24” bar clamps. I used these because the large foot applied even pressure on the face of the fretboard. Again, I left it to dry for 24 hours.

Finally, there was one loose fret and a couple of places where the fretboard didn’t seat fully, so I used water-thin super glue to wick into those gaps and used the bar clamps again to apply even pressure.

With the exception of the fret I replaced being a bit too low, and the chunk missing from the back of the neck, it is as good as new! There is only a very slight buzz on one string due to the fret I replaced being too low and I’ve since been too lazy to fix it. Otherwise the uke plays as good as it did before the accident.  I think the key is patience with this type of project. We learned that with the uke kit we built previously. You absolutely can’t rush things else you will ruin them.

Building a Zen Meditation or Seiza Bench for better Posture at my Desk

I used to have a standing desk for years, but since we moved, I haven’t found a similar solution. My posture is suffering because of it. I discovered that by resting on my knees at my computer desk, and raising my computer screen a bit I can get back in to the correct posture. I realized I could build a seiza bench would be the best solution to add a bit of support and reduce stress on my knees.

I began with an exhaustive search online but ended up just making my own. The design I liked most was this travel seiza bench from Sakura Co.  While they list the dimensions on their site, I found that to be too short for my needs. I experimented, having my wife help measure how high my butt was from the ground when I was in the best position, but the best experimentation was when I went to build the bench in the garage. I sat on a bucket which happened to feel like a comfortable height. I have a variety of buckets in the garage so I tried them all out. I took measurements of the ones I liked most and went about freestyling the design.

I had an old 7 1/2” wide by 3/4” thick pine board from a previous project laying around the garage, so I began with that. I laid out the 2 heights I measured and drew a diagonal line to connect them. This will be the final angle of the bench. Then I went about measuring and calculating the tab lengths. Here’s what I ended up with.

image

In that pic, I had already made my first cut. Basically the back of the bench is 11 3/4” tall, the front is 10 1/4” tall. this is a pretty steep angle, but I feels acceptable so far as I’ve been using it, though I haven’t used it much yet and I may end up making a different angled bench.

The tab that sticks up at the top rises about 2 1/8” above where the bottom of the seat will be. It has to be high enough to go through the seat and accept the holding pin to mount the legs with a bit of material on top of the holding pin. That’s how I came up with that measurement.

I tweaked the design from the inspiration more by having my tabs move at a 90 degree angle from the slant, rather than follow the edge of the board as in the bench form Sakura Co. This makes is far easier to construct.

This entire project can be built using 1 pine board, electric drill with a 3/4” drill bit, and a jigsaw. I had other tools available so I used a circular saw to cut the board all the way across as you see in the above pic.

Next, I used the bandsaw to cut the excess material away from the tabs. You can see that I forgot to tune my bandsaw before cutting.  This board looks pretty janky.

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At this point, I messed again when cutting out the hole for the pin to fit into. I thought it’d be smart to drill a couple of holes just big enough for my jigsaw blade to fit into. I should have used the largest drill bit that would fit the hole instead.  This made for a nasty cut where the pin is supposed to be tight.

The idea is to drill a hole or two to give your jigsaw blade enough room to cut the edges and the corners. It takes a few passes from different angles, but I got it done. Now I got my 30+ year old jigsaw out of someone’s garbage can… it’s missing a few screws, but gets the job done, even if it isn’t very clean.

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The next board was easier to cut since I tuned up the bandsaw. It came out with much cleaner edges.

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I made the same mistake of using too small a bit to drill the hole, however I did learn something.  When drilling the hole in the first leg using the spade bit, I just drilled all the way through.  This tore out the back and made a nasty edge.

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This time, I drilled a into the piece from one side until just the tip of the spade bit poked through the back and I stopped. I flipped the piece over and placed the tip into the hole to line it up and then drilled the rest of the way through the wood. This left a much cleaner edge.

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I’ll spare you the carnage from the jigsaw. It was better than the first one, but not good overall.

I then moved on to the seat. I cut a 22” long piece from the board. I measured 2 inches from each end to begin marking where I wanted the legs to mount. Due to the slat, the legs will stick out a bit from the seat about 3/8”.  I decided to make the front of the legs flush with the seat and allow that excess to hang out the back. No one will notice that, and I won’t be annoyed by it while using it.   I drew an arrow on each of the 3 parts to determine which side was the front. Then I traced the outline of the tabs for each leg on the seat board. I want as tight a fit as possible with this so it doesn’t wobble when I sit on it. Since each leg’s tab is a bit different due to my excrement woodworking skills, tracing the actual shape of the tab will get me a closer fit.

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This is when I wised up about the spade bits. I mounted a 3/4” spade bit into my drill press and used the trick of going not quite all the way through the board, flipping it and drilling from the other side for a cleaner hole. Somehow I still managed not to get it perfect.

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I made the edges and corners straight with the jigsaw again on each side.

Then I used some scrap wood and cut the pins on the bandsaw. I didn’t get a pic of them alone, but I made them wedge shaped with 2 right angles and a slanted side. One side 3/4” tall and the other 2 1/4” tall. The bottom edge (the longest edge which is at right angles to the sides) is 3 1/4” long.  I made two of them.

To even out some of the nasty straight cuts, I went to my trust poor-man’s belt sander setup by clamping my handheld belt sander in my workmate project center and locked the trigger in the on position as I maneuvered the parts on the 150 grit sandpaper. Put  the puzzle together and you have a bench!

I use a pillow on the ground under my knees to add some comfort, and I may eventually get either a couple of gardening knee rests (one for my knees and the other for my bum) or an hammock pillow for the seat. Given the ridiculous costs of hammock pillows though, I might just make a thin seat rest pillow myself to tie around the seat.