Provisional Press

Last year I bought a printing press kit from Provisional Press. I used to have access to a press when I worked at the museum, and I’ve also borrowed a press from a friend of mine in the past, but most of my “home made” prints have been done with a baren. (I even 3D printed one.) Can you do prints with a baren? Totally, but using a press does make things much easier and more consistent.

I got the base kit with no extras (more on that later) so that’s what you see in these photos. Once you do the assembly, which consists of gluing and screwing things together, you can add in the metal plate as the base. If you use letterpress the metal base comes in handy, and you can grab some galley magnets but honestly I’ll probably just make my own plates like I normally do.

It comes with two “galley high” blocks, which you use to square things up properly so the roller is consistent across the press. There a process involving adding tape under the inside rails before you screw them in place.

Here’s what the bottom looks like. You’ll see that some things are not jammed tightly together. Maybe because wood can expand and contract over time and based on temperature and humidity? I’m not sure…

Here you can see some (blue) tape sticking out a bit. You basically add strips of tape to get things level with the roller. It didn’t take long, but it’s one of those things you should take your time with and get right, since once you screw things together you probably don’t want to unscrew them.

The roller is a large piece of PVC or “Charlotte” pipe. I used a bit of acetone to remove the red “Charlotte” lettering on it. It’s still slightly visible though, which is fine.

My plates are typically made from 3mm (1/8″) Baltic Birch plywood. I have a pretty good supply of scrap due to the fact we use a ton of it at work and often get strips left over that are around 4″ tall by 24″ long. I tend to cut them into smaller pieces to fit in my laser cutter. Making 3″ x 5″ plates is quick and easy and I can probably make 50 more with the scrap I have on hand right now.

To get the plate to the right height I dropped in a piece of 3/4″ plywood I had lying around, with some old cereal box board and sheets of paper underneath to get just the right height. It works well and if I consistently use the same wood I shouldn’t have to adjust things too much.

Hey, I made a print! You can see I added two pieces of soft felt as my “press blankets” which seemed to work well. The one upgrade I’ve already added is the 9″x17″ Grid Base which I should have grabbed when I ordered but for some reason did not. It makes it much easier to line things up and to clean things up.

About the assembly… It went well, but it did take some time. I think part of it was that since there was gluing involved I really wanted to get things right. The other issue (for me) is that the last few things I’ve built have been CNC machines, where getting things exact and precise is extremely important. This press is… a bit less so in that regard. It’s all wood, but you end up shimming things to get stuff aligned, and it just feels like there’s some wiggle room. Having built one I’m pretty sure I could build another in half the time.

I will recommend this: Watch all the videos and read everything completely before you start the assembly. Some of the parts do not match up exactly, which was confusing for a bit. The videos are not professionally produced, but hey, it’s a DIY kit, so that’s fine. Watch them all before starting.

For the pins that keep the top roller from coming off, I did not glue them in place, as I wanted them to be removable in case I take the top roller part off for some reason. (Maybe for transport.) I just wrapped some tape around them to press fit into place. I did stain the side parts of the top roller section, and thought about staining more of the press, but you should do all that before assembly, and I didn’t want to spend the time doing that. I think it looks pretty good as it is. I mainly stained the side parts because they are 1/4″ laser cut pieces and I just wanted them to look a little nicer.

Oh, if you want to see a bunch of fun stuff from the Provisional Press crew, check out their Instagram account. Also, you can totally build your own! The plans for this press are open source.

I’ll probably do a follow-up post once I’ve got a bit more time into using it. So Stay Tuned!


Little CNC Milling Machine (Part II)

CNC Machine

Hopefully you’ve read Little CNC Milling Machine (Part I) in which I completed the mechanical build of a tiny CNC machine. Here’s Part II!

CNC Machine Electronics

The electronics didn’t take much time at all, it was pretty much “plug and play” as far as connecting the three stepper motors and the spindle. No stripping, cutting or crimping wires. The only issue I had was once I tried running it nothing was happening. Turns out the power supply was DOA. I found a 16 volt laptop power supply in my junk bin and tried that, and it still didn’t work (or so I thought.) I ended up cutting the barrel jack off that power supply and putting it on a 24 volt supply I found. It was then I realized that the spindle wasn’t responding because I never set the “spindle speed”. So yeah, steppers worked fine with the 16 volt power supply (but not the original 24 volt supply I got) but the spindle didn’t go, because I’m a fool. All good now! I’ve got functioning 24 volt power supply and a functioning CNC machine.

CNC Machine Electronics

I’ve used Grbl before, usually with an Arduino and a CNC Shield with some steppers. Some of these kits seem to use an Arduino Nano, but this one is its own board with an ATmega328P and a CH340 chip. So yeah, an Arduino with Grbl 0.9 pre-loaded.

There are no endstops, but it looks like there’s room on the board to add them in the future. I can think of a few other improvements as well. I may add an e-stop, or just an “on/off” switch for the power supply. One nice thing about these machines is that if you make a mistake, like jogging the head too far in one direction, you can just cut power to the motors and the software will keep going, assuming the motors are moving, and then once the software is done, you can resupply power and try again.

Oh, you might also notice that next to the spindle connector on the board is a spot to plug in the laser. Yes, there’s also a 500mw laser that can be put in place of the spindle. I’ve not really tried that yet, and have to figure out the software to control it first. (I’ll get into software in a future post.)

CNC Machine Bed

Another area that could use some improvement is the bed. Attaching things with the screws meant to attach things to the Aluminum extrusion is not great. I’ll work on a better clamping system. (Maybe a 3D printed piece, not sure yet.)

You might also notice I left the lead screws hanging in mid-air. I did have a little bit of a binding issue with the x axis, so I just removed both lead screw holders. I think it’ll work fine without them, as the lead screws are not that long.

CNC Machine Collet

The machine came with two tiny collets that allow you to attach bits to the spindle shaft. It also came with super-small set screws. I’m pretty sure I’ll lose the screws, but…

M3 Set Screws

…luckily a few years ago my friends at Evil Mad Scientist Laboratories sent me a lifetime supply of M3 set screws of various sizes. I think I’m good!

CNC Machine Electronics

And yes, I did actually mill something. I’ll cover that in the next post. Overall I have to say I’ve been pleased with this machine (so far, it’s still early, obviously.) It was easy to put together and it works. Once I get things dialed in I’ll look into milling PCBs, and foam, and wax, and chocolate…

Stay Tuned!


Little CNC Milling Machine (Part I)

Little CNC Mill

I’ve completed the mechanical build of a small CNC mill/engraver. I’ve seen these on eBay from various sellers (like this, this, this, and this) and I’ve even seen one on Amazon from LinkSprite. I didn’t order from any of those sellers…

Somehow I happened across a blog post at TC Maker about a CNC Building Class at The Hack Factory. While I would have loved to have attended the class, I couldn’t make it, but I got in touch with Alex to ask a few questions, and the next thing you know I’m ordering a kit from him.

Alex said he’ll be doing another class, and hopes to sell these to other people as well. (I guess I’m one of the first customers?) I was attracted to the mill because it’s small (my workshop is cramped already) and it runs Grbl. I’m hoping to mill PCBs with it, and other small things. If I get really ambitious I can extend the machine with some longer lead screws and Aluminum extrusion. But first I have to get it working… I still have the wiring and electronics to deal with.

I’ll go through a bit more about building it in this post, and probably follow up with a few more posts once it’s complete.

Little CNC Mill

First, let’s talk about the instructions. Remember, Alex does an entire class on building this, which I did not attend, but I’ve built a few CNC machines in the past, so I wasn’t too worried. I did get a construction manual, and it was helpful, though in the end it sort of reminded me of building my RepRap. At some point the instructions seem to lose their usefulness and you just have to figure things out. Luckily, there’s the Internet.

The page titled DIY CNC 3 Axis Engraver Machine PCB Milling Wood Carving Router Kit Arduino Grbl is helpful, as is the video LinkSprite DIY CNC 3 Axis Engraver Machine installation tutorial. I should mention that these kits come from different sellers, and they all seem just a slight bit different. Minor things here and there, so again, if you can figure things out on your own, it’s not that bad.

There’s some videos from Jingfeng Liu that might be useful, including LinkSprite CNC Kit base Video 1, How to assemble LinkSprite CNC kit front video 1, and How to assemble LinkSprite CNC kit front video 2. Again, use them as loose guides.

Little CNC Mill

The worst problem I had during the mechanical build was dealing with the rod holders. Now, I’ve used rod holders before to hold smooth rods, and didn’t have issues, but these caused me some heartache. The one on the front right was the first I dealt with. I tried to tighten it up on the rod, and I could not get it tight enough to hold the rod. After I sent an hex key flying across the room, I tried one more time to tighten it up enough by putting a Torx bit in a drill (I know, bad idea.) This just stripped out the screw, and now it’s in there, and not coming out. (Oh, before I over-tightened/stripped it, I tried to put a little tape on the rod. Kapton tape seemed thin enough, but was still too thick.)

Little CNC Mill

I still had three rod holders to deal with, so I took a different approach. I put one in the vise and cranked on it to pre-bend the metal just enough to hold the rod tight, but not too tight. Well, I managed to do that with one of the rod holders. The next one I cranked too much, and then had to pry open a bit with a slotted screwdriver. (You can see in the photo above a little bit of the damage from that. In the end I got them all working good enough, except for the first one, but since the back rod holder is good, I may not have to worry about the front one being tight enough. (It doesn’t wobble, but I was able to rotate the rod when it was just in the front holder.)

CNC Machine

There’s a 3D printed part on the front for the lead screw to set in, with a bearing. I have not mounted this yet, as I’m not sure it’s a good idea. Some builds use this, or a metal plate, and some let the lead screw hang free in the air. (The x axis has a similar holder.) As this is not a super-precise machine, constraining the lead screws might not be the best thing…

Little CNC Mill

The shaft coupling is one rigid piece, which means that if not perfectly aligned, constraining it on the other end could cause binding while trying to turn. I’ve used flexible couplings before and they might be a better option. Again, I’ll probably get the machine up and running first to check the performance before I think about upgrades. (I talked to Alex and he suggested that flex couplings might not work as well as I think they would. I’ll do more research on it.)

Little CNC Mill

The mechanical build took an evening, not a late-night evening, but a full evening. I expect the electrical portion to take maybe a few hours at most, including getting it up and running. Hopefully I’ll find some time this week to get that going, and report back.

See Also: Little CNC Milling Machine (Part II)