– Ben Martens


CNC Cherry Bowl

In 2016, we decided to take down two scraggly cherry trees along our driveway. Check out 3-year-old Elijah looking on as Logan and I took the trees down.

There was hardly much wood in them, but I saved some of the bigger pieces anyway. After drying out, one piece of the wood got turned into a cross that hangs in our front entryway. But I had another half dozen or so pieces sitting around with no plan. I had been thinking about trying to make a bowl on the CNC anyway, so I decided to use this wood for that project.

I spent a lot of time with a segmented bowl calculator trying to figure out the specific angles I’d need to cut 8 trapezoids for each layer. Eventually I felt good about the calculations and since that program spits out SVG files, I decided to just cut them on the CNC and know that the angles would be perfect instead of trying to do it on the table saw. The table saw would have been a lot faster, but one bonus of the CNC was that I could do a facing operations on each board to get them to exactly the same thickness. Using the planer for that would have been difficult since the pieces were too short for the planer.

I glued each layer individually and clamped it with hose clamps. Once each layer was done, I glued them all together. Then it was time to model the actual bowl in Fusion 360. The trick was that I had to make sure that the bowl perfectly fit inside the blank. Here again, the SVG files from the calculator came in handy because I could pull them into Fusion and draw the blank pretty much exactly as it existed in the real world. I also had to be careful not to make the bowl too steep since my router body would crash into it while carving out the bottom of the bowl.

Then it was time to program the actual cut in Fusion. I started with the bowl upside down. I programmed a dummy cut around my stock which would give me confidence that I had things calculated correctly. Then I did a roughing pass with a 1/4″ end mill to get rid of the bulk of the material. The picture below shows that roughing pass about halfway complete. The whole pass took 1.5-2 hours.

I then switched to a 1/4″ ball nose bit and took very small passes back and forth across the bowl to give a pretty smooth finish. It still needed sanding, but it was very close to the final surface.

Next I flipped the bowl over and did the same process on the inside of the bowl.

While doing the inside of the bowl, I had an accident where the bit plunged way down into the blank where it shouldn’t have. The origin of my model had been set incorrectly. Chatting about it with Luke, he suggested that I fill the hole with a dowel, and I happened to have a cherry dowel that was exactly the right size. Thankfully that whole mistake ended up getting cut away, so it didn’t impact the final product.

It was also a challenge to hold the bowl to the surface of the table. Since I was machining the whole surface, there was nothing to clamp to. So instead, I put blue painters tape on the bottom of the blank and on the table. Then I glued them together with super glue. It created a strong bond that I was able to break later without damaging the bowl or the CNC table.

I added some boiled linseed oil as the finish and now it’s done! I don’t have any big plans for the bowl, but I’m happy to have made it successfully through this project. I didn’t really have enough wood to make another one if I screwed up and I was too lazy to make a duplicate blank out of cheaper boards.

If I ever do this again, there will be a few changes:

  • I didn’t rotate the second layer correctly. The cracks line up with the base/first layer. It doesn’t look too bad from the inside of the bowl, but it looks goofier from the outside.
  • I should have taken more time sanding the layers flat before gluing them together into the blank. I thought I had them flat enough, but there are some segments that have a tiny gap to the segment above them.
  • I need to experiment more with the program and how fast I run the bit. This whole bowl was something like 6 or 7 hours of machine time plus all the setup time around it.

Ninjago Sword Prop

As we approached Halloween, we went through a lot of ideas for Elijah’s costume. Since we haven’t done trick-or-treating for the last couple of years, we decided to let him get an actual costume. He chose to be the green ninja from Lego Ninjago. I couldn’t resist making part of his costume so I set out to make a dragon sword to go with it.

I wouldn’t have gotten far if I hadn’t found an existing model, but luckily Thingiverse came through for me. I pulled that model into Fusion 360 and spent hours trying to figure out how to cut it nicely on the CNC machine without taking forever. I was able to apply a lot of learnings from my Luther Rose project.

The final product was carved out of a scrap 2×4 and I did it in two separate halves. If I had it to do over again, I think I would learn how to program in a cut that I can flip over halfway through because the seam between the two pieces was visible even in the finished product.

Once the pieces were glued together, I applied a few coats of a filler primer with sanding in between. The sanding took a long time with all the nooks and crannies. Thankfully, Elijah got interested in the project at this point and helped with the sanding.

We finished it off with a couple coats of high-quality gold paint. The final product looked amazing! It makes me want to do another one at the biggest scale that my CNC could handle…

Wooden Luther Roses

All of my CNC work up to this point has been two dimensional. I draw lines and then have the machine cut them to a certain depth. But there’s a whole other world of three dimensional carving that I have never tried so I invented a project to learn a bit about that.

For a model, I picked a Luther Rose model from Thingiverse. I brought it into Fusion 360 and spent a long time learning about all the different 3D tool paths that it has. I knew that I wanted to do one roughing pass to get rid of most of the material and then do a finishing pass with a much smaller bit to get the detail. I planned the first pass with a 1/8″ endmill and then a follow up with a 1/16″ ball nose mill. (I had to buy a special collect to hold the 1/16″ endmill because it only had a 1/8″ shank.)

From there it was off to the CNC to try it out. What followed was a long series of errors. The board would slip, I’d lose my zero when I changed bits and not be able to reset it, the bit would slip in the chuck etc. I started with some cheap pine boards and eventually moved to 3″ walnut squares.

These are all failures… err… steps in the learning process.

With much perseverance, I finally got it dialed in! On the 3″ walnut pieces, the first pass took about an hour and then the second pass would take 3-4 hours. Usually I stay in the garage when the CNC is running, but this was the first time that I let it run attended. I would go out and check on it regularly and I’d watch it via the camera in the garage. Working from home was a big advantage because I could run it throughout the day while I worked.

After I made four successful roses and ran out of the walnut board, I felt like I still had more to learn. I also had some very wide scraps of wood leftover from the dresser build. So next I set out to make a couple 8″ roses out of cherry. I switched to a 1/4″ endmill for the first pass and an 1/8″ ball mill for the finishing pass to keep the total time down. Neither one of those cherry roses was flawless, but with a lot of sanding afterwards, they look great. And then the pièce de résistance was a 9.5″ wide piece of walnut. That one started warping a bit as I cut it, but I was able to salvage it with a lot of hand sanding.

It was a huge learning experience, but it was also a lot of fun. I feel like I’ve unlocked a new woodworking skill! There’s still plenty to learn, but I won’t avoid a project if I need to do some 3D stuff on the CNC.

After the first pass with the big piece of walnut
Second pass

Follow me on Instagram @martenswoodworks. I usually post mid-project updates to stories and then make posts for the finished projects.

Shop Tour – Organization

Marc over at The Wood Whisperer sent a message to members of his guild and asked us for videos of our shops. He’s working on a new video that somehow incorporates videos from normal humans. I have no idea how that will work, but I decided to film a quick video and send it to him. We’ll see how that plays out but I thought that I’d share it here too. The ask was to focus on organization so I hit few points in my shop that I think are interesting.

It’s interesting looking back at photos and videos I shot in the garage in the past. I don’t feel like I change/update my workshop area that often, but it’s in a constant state of flux. It just keeps getting a little better every year.

Gridfinity Organization System

I have a pile of random screws, nuts, bolts, and washers in my shop. I buy little bags or boxes of random sizes of things, use a third of them, and then the bags sit around forever because they are such a mess that I can never find them when I need them. The whole thing seemed so random that I never really put much time into looking for an organization system, but now that I have 3D printer, I have the ability to custom make exactly what I need!

A couple of months ago, Zack Freedman released his “Gridfinity” system. The system is based on a grid of baseplates and then each bin/holder can be easily stacked in various combinations. I was downloaded exactly the bins I wanted, customized his model to make some new bins, and made a series of prints that resulted in a lot more organization. This is a project that I’ll keep adding to, but for now it feels good to have brought some order to the chaos. Not bad for ~$10 in filament!

3D Printer Enclosure

Some people build elaborate 3D printer enclosures to do things like control temperature during prints. I haven’t done anything that complicated yet, but I do like keeping dust and cat hair off the printer. So when it’s not in use, I have been setting a cardboard box over the top of it. It works, but it looks ugly.

The other problem I needed to solve is that filament is hydroscopic. If it sucks up too much moisture from the air, it can cause print problems. I’ve been storing the filament rolls in Ziploc bags with desiccant packs in them. Again, this works fine, but it looks messy and when I want to print, I have to pull the roll out of the bag and get it set into the rollers so it will feed into the printer, etc.

I set out to make an enclosure and dry box that would solve these problems. I’m not sure I’m there yet, but I’m at least at a stopping point for now.

For the enclosure, I decided to go with a minimalistic design. I just wanted to have sticks making a cube and then fill in the panels with either plywood or plexiglass. I modeled up corner brackets in Fusion360 and 3D printed them.

Acrylic seemed a bit expensive, and I thought I could save myself some money by purchasing cheap poster frames. That choice ended up making this a very frustrating project. The plastic frames technically did work but they were extremely thin and difficult to work with. They got scratched up and cracked during the project.

I further complicated the box by making it the wrong size the first time. I forgot how much the bed of the printer slides back and forth so I had to take it apart, cut some of my extra plastic, and try again.

The door was the last piece of the puzzle and by that point, I was tired of the project so I made a frame to hold a plastic sheet and then used rare earth magnets so that it would stick to the face of the enclosure but be easily removable.

Next up was the dry box for the filament. That part went much smoother because Becky Stern has an excellent Instructable article. I 3D printed my own nuts and bolts (with a hole down the middle for filament to feed through) and also printed hangers for the PVC pipe that the filament rolls sit on.

After what seemed like forever, I attached a battery powered LED light to the roof of the enclosure and called it good for now. Maybe this will last me for years, but I could also see getting frustrated with it and wanted to redo it. The basic design is ok but I do want to change the plastic panels, the way the door works, and give it a better paint job. I do really like that I can just leave the filament in the machine instead of unloading it and storing it away every time though.

Church AV Equipment

The audio-visual setup at our church is not very impressive. We don’t ask a lot of it. The main functions are:

  1. Amplifying pastor’s voice
  2. Providing a feed to the screen in the nursery area
  3. Recording the service

Check out this “before” picture. Believe it or not, this is after I had started replacing some gear and throwing stuff away.

Yes that is a CRT TV and yes it was used every Sunday.

I’m the one who ends up running the equipment most of the time so I decided it was time to take this area on as a project. If you’ve been following my @martenswoodworks account then you’ve seen some progress updates in the stories, but over the last couple months I’ve been slowly building up the new solution piece by piece. I wasn’t confident enough to do it all at once since there are so many unique constraints to a project at church. Things rarely play out as expected. This was my rough plan going into it:

Along the way, I was happy to find someone at work who was selling three 24″ monitors and a monitor arm to hold them all. That was the perfect addition to the project because I’m always nervous about stuff toppling over the edge and landing on people. Here’s a look at the end result:

The screen on the left is the video switcher. It takes input from up to four cameras though we only use two today and it combines in the audio from our audio mixer. It records straight to USB (or in the future can live stream to YouTube.) The middle screen is a PC that I’ll use for uploading to YouTube, using extra features of the video switcher, and, in the future, controlling the TV in front of the church. The right screen is for our security cameras.

If I wanted to post a sermon with the old setup, I would come home with two SD cards from the video cameras and a DVD with audio from the mixer. I would have to edit that all together and then upload it to YouTube. That was a couple hours of work for me when I got home every Sunday. So you can imagine my joy when yesterday I recorded the whole service to a USB stick and uploaded it directly to YouTube before I left church!

I hesitate to post this because there are always more things that can be improved (cable management for one), but I do feel like this is in a place where I can slow down for a bit. Not only is this a nicer to use, it opens more possibilities down the road and hopefully it’s not so intimidating for others to learn.

MC Etcher Drag Engraver

For Christmas, my father-in-law gave me the 120 degree MC Etcher diamond drag engraver bit from Carbide 3D. It fits into my CNC router but is used without the router powered on. The tip is spring loaded so that it will have constant pressure with the surface as it gets dragged along. You can drag engrave many different materials so on a trip to Home Depot, I randomly picked out a couple tiles.

My first attempt was making a sign for the reloading bench that my father-in-law was building. I drew up a design with a herringbone background not knowing if it would work. The sound is a bit like nails on a chalkboard, but it worked great! I ended up going over parts of the design multiple times to get a more defined line.

Later I also made a plaque for the garden bench that I posted about before.

I’m looking forward to trying some other materials too. I think a smooth granite tile could make really nice award plaque and some acrylic could be neat with edge lighting. The possibilities are endless and it’s a fun tool to have at my disposal.

Cedar Garden Bench

Elijah’s school is having another charity auction this year. I got ahead of the game and donated another wooden flag since those are fairly simple and it brought in a lot of money last year. A couple weeks ago, the school posted on the parent teacher group asking if someone would be willing to make a garden/potting bench. I don’t have enough to do so I volunteered.

My first step was downloading the Potting Bench plans from I Like To Make Stuff. This project isn’t rocket science, but it’s so nice to have all that thinking done for me. I was able to walk into Home Depot and get the right amount of wood in a single trip. I made a few changes to the plans though: I didn’t add the sink in the top and I made two shelves along the top instead of one. Since it was all screws and butt joints, I was able to finish it in a weekend.

To add a little more to the project, I tried out my new diamond drag engraver bit for the CNC machine. I used it on a random tile that I bought at Home Depot. I picked a vaguely garden-related Bible verse (you have to squint and kind of take it out of context) and found a good SVG on Etsy that I could alter for my purposes. I didn’t etch is super deep, but when you’re up close, it’s easy to read the message and see the flowers on the sides.

I think that this is going to be part of a classroom project. The kids will donate related gardening supplies and then it will all get auctioned as one unit.

And since I was curious about wood prices when I started this project, I’ll share that the wood and a box of screws came to just under $200. It’s cedar so it will weather nicely outside or easily accept stain, but you could probably save a little money if it was pine.

Large Wood Wall Clock

The idea of making a large wall clock has been floating around in my mind for a while. My CNC often gets used for small cuts so the idea of doing something that uses all the real estate was appealing.

I started by gluing up a panel of 1×8″ pine boards to make a blank big enough for the clock. It’s always tricky to get a nice flat panel, especially when using cheap boards from the home center, but it came out reasonably flat and I kept it clamped down to the surface of my CNC machine when I wasn’t out there working on it.

The next task was cutting the face of the clock out of 1/4″ MDF. Instead of starting from scratch, I purchased a vector art design from Etsy, but with all the modifications I had to make to it, I might have been better starting from scratch (or at least from a different store.) I eventually got it all programmed and even though it would take a lot longer, I decided to run the whole pattern with a 1/8″ bit instead of a 1/4″ bit. That would give me more definition in any sharp corners. The whole cut ended up taking around 3 hours with some stopping in the middle to make adjustments.

After a lot of sanding, I finished the back with some stain and used an off-white spray paint for the face. I usually got for pure white but decided to try off-white this time. I wasn’t sold on the idea until I got to the very end of the project.

For the clock parts, I used I had used them once before and was happy with their stuff. This time I purchased their high torque clock movement to support moving those giant hands. When the parts arrived, I sprayed the white hands to be the same off-white color as the face.

I cut the blank into a giant circle on the CNC and I was careful to hole right at the center which came in handy for finding the same center again later and for mounting the movement. With the blank flipped over, I pocketed in a whole for the movement and I also added some keyhole slots for mounting it on the wall.

We hung it above the fireplace in the front room and while it’s a fun piece of art, it’s a little tricky to read the time from it. The counterweight on the minute hand and the rings that encapsulate the Roman numerals are all distracting. I don’t know that I’d change the design at all though.

I see these on Etsy and Instagram and feel “meh” about them in general, but I’m super happy with how this project came out. It wasn’t a huge project but it had enough small new things in it to really entertain me.

Follow my woodworking on Instagram @martenswoodworks