Got into one of those wars with myself today. Nothing seemed to be going right on a project, and at first I was working through and around the problems. But, problem after problem kept piling up. It also didn’t help that it’s a gazillion degrees in the shop. Then I started to get frustrated and impatient, and started trying to force things to be the way I wanted them to be, and damaged something I had been working on all day. The trick is to quit before getting to that state. When will I ever learn?
If you look on the Maslow CNC forums, you will see that one of the greatest challenges that Maslow users face is the mechanics of the z-axis. The height adjustment on the recommended router, the Ridgid 2200, was never meant to be used in the way that it is on the Maslow. It can be altered to be OK on cuts with a limited number of z-axis moves, like furniture. But if you want to do something with a lot more depth movement, like some kinds of artwork, such as my CNC Halftone experiments or logos, it can start to get dicey. My guess is that the main issue is the accumulation of errors due to slop in the router’s height adjustment mechanism that the Maslow uses for z-axis moves (not an original idea).
3D halftone image experimentSerifs & Whiskey logo
I should state before going into the things I’ve tried, and the recommendations I have that I am not an engineer of any kind (although my last job title before becoming a full time maker was Desktop Support Engineer). Also, if you are a Maslow user, or thinking of becoming one, you should definitely go to the Maslow forums https://forums.maslowcnc.com to get answers and advice from people who are far more experienced in this stuff than I am. My general approach to the Maslow is: I have technical skills and the Maslow is within the range of those skills, but I’m really more interested in the art I can make with it. Upgrading the machine was done out of necessity, and not because I wanted the engineering challenge. Making halftone images, for example, was something I had in mind to make from the beginning, and I did not know I’d be pushing the limits of what the Maslow can do.
There are a number of ways recommended on the forums to take the slop out of the z-axis mechanism on the Ridgid router:
Add a some elastic over the top of the router and anchor it to the sled. https://forums.maslowcnc.com/t/z-axis-bungee-to-ensure-correct-depth/481 In my opinion, this should not be an option. Everyone on the forums will remind you to not put too much tension on because that might cause the router spindle to slip out of the shallow slot that connects it to the z-axis mechanism (what I learned is called a “mechanical fuse”). I have found that it is not too difficult to achieve sufficient force to take out most of the z-axis slop without causing the mechanical fuse to trip.
Attach a bushing to the z-axis clip to keep it perpendicular to the screw. This is something that didn’t work for me and caused the mechanical fuse to trip, I suspect because I used my own solution, but I’m not sure. I suggest that if you want to go this route that you carefully follow the instructions here: https://forums.maslowcnc.com/t/cheap-fixes-for-z-axis-slop-on-the-ridgid-r22002/4031/5
The other solution to the z-axis problem is to discard the Rigid router mechanism entirely, and build a replacement one. That’ll be Part 2.
Finally finished part 2 of my Pentaflake Tabletop build video. I’m looking for work, so if you’re interested in me making something like this for you, contact me via the email address in the sidebar.
I’m still working on the video, but I wanted to get something up on HipNerd.com about finishing this project, since I already posted to social media about it.
I had more trouble with the Maslow, but finally got a good cut.
Pentaflake pattern being cut into plywood by Maslow CNC.
The bit was dull from the tests I ran previously, so I changed bits halfway through, then re-ran the program to clean up the hairy stuff from the dull bit. Finally, something worked in my favor, and it cleaned up well.
Before and after changing bits.
I sanded the insides of the cutouts by cutting up a sanding sponge, folding it over and zip-tying it to a dowel, then putting the dowel in my drill.
I cut the tabletop into a circle using a router on a jig.
Cutting the circle using a router on a jig.
I painted a coat of clear epoxy resin into the cutouts to seal, then poured the the colored epoxy using condiment dispensers.
Tabletop with Seal Coat and Colored Epoxy
I sanded off the excess epoxy with 80 grit sandpaper, working in sections.
Sanding in progress
I sanded everything smooth, working my way to a final 400 grit hand sanding. I put some edge banding on to hide the plywood edge. Then, I put on three coats of varnish.
Sanded and Varnished
I’m really happy with the way this came out, and looking forward to some more projects with my Maslow.
For test #5 (there’s been so many tests, I think this was #5) of the Pentaflake Tabletop, I modified the clip on the router with a big bushing with plenty of surface area for epoxying, and used some epoxy putty made for gluing metal to metal (JB Weld SteelStik). End result: a really solid bushing, which keeps the clip perpendicular to the z-axis screw.
Added a bushing to the clip on the router’s z-axis control to eliminate slop.
One of the issues I’m having with with my cutting the pentaflake pattern for my Backyard Tabletop project is that the router bit stops in one of the corners of each pentagon shape before moving up. This causes the bit to rub against the side of the cut as it raises, burning the wood, heating and dulling the bit. The problem gets worse as the job progresses, as you can see in this picture:
Side view of the pentaflake pattern showing burn marks getting worse across the piece.
What I found out on the Maslow forums is that this is a common machining problem for which there is a common machining solution: something called ‘lead-out’, where the bit moves away from the edge of the cut before performing the z-axis move. Unfortunately, the software I’m using, Easel easel.inventables.com, does not support that function. The other common software used in the Maslow community, MakerCAM MakerCAM, doesn’t even seem to be working, it’s an online tool (as is Easel) and I can’t connect to the site. I looked at some videos on how to use Fusion360, which I have some experience with for 3D printing, but it seemed quite complicated in comparison to Easel or MakerCAM.
I decided to try Fusion360 anyway, first bringing in the .svg file I made in Inkscape, but that bogged down my computer, and brought out the pinwheel of death. I then tried generating the pattern in Fusion, but after the pattern got over 30 elements or so, it bogged down my computer again. Don’t know if it’s Fusion or my computer (an older MacBook Pro), but I gave up on it at that point.
I’ve modified g-code files before for 3D printing. G-code is human readable, and actually pretty easy to understand. I knew that the best way to modify the file would be to use regex, though I hadn’t used regular expressions in a while. Fortunately, there are a lot of online resources for learning regex, and the RegexOne interactive tutorial got me up and running pretty quickly.
I brought the .nc file into the Atom editor, https://atom.io, and wrote a regex to find the entry point for each pentagon shape in the g-code. I added a g-code command to move to that point before each z-axis up move, essentially creating a lead-out.
Editing G-code in Atom using regex.
I loaded the .nc file into Ground Control (the software for controlling the Maslow), and it looks good, but I won’t know for sure until I run it. I reattached the bushing (see previous post) using 2 part epoxy, and I’m waiting for it to cure overnight before testing again.
I built a Maslow CNC. This video is part one of the build process—the electronics and assembling the frame. The Maslow is a relatively inexpensive, open source CNC kit. The kit comes with the electronics and specialty hardware, and you provide the lumber, router, and a computer (and a dust control system is a good idea, too). It’s a hanging router, much like a hanging plotter, and is capable of cutting an entire sheet of 4X8 plywood (with some margins). It can also cut thin aluminum, pretty much any material that the router you equip it with is able to cut. I’m very excited about the creative possibilities that this machine will open up for me.
