PM 833TV & ClearPath, IP53 or IP67?

CNC Mill Conversions and Builds
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The mill should be on it’s way and I ordered a kit from AZcnc kits. Dave says the CPM-SDSK-3421S-RLN for x and y axis and the CPM-SDSK-3432S-RLN for z axis have more than enough power and a brake is not needed on z unless the ball screw nut ends up with play in it. The brake adds another $300 to the cost and an alternative is to park the spindle on a block of wood.

Most of my fabrication is with steel right now, as it cuts better on the plasma table I built and it is cheaper and easier to weld, but I’m no stranger to working on aluminum and stainless. Most of the steel work is just drilling, tapping, or slotting on the clapped out RF30 that I have now. With a good cnc mill, it wouldn’t surprise me if I end up doing more out of aluminum with how easily it cuts. Most of my work is one off or a small quantity of parts for one project so accuracy and reliability are more important than speed.

Space is limited in my shop, so the shorter ClearPath motors are a plus and quieter tools are nice. The 833 kind of ticks all the boxes and even with servos beats the price of ordering a tormach system.

Most of the rest of the build will follow Dr. D-Flo’s build with linux cnc and the board he used.

Does anyone have input on the IP53 rating of the base motor vs. the option for IP67 and the shaft seal, for use with flood coolant? Teknic says to use grease on the connectors at the motor for the standard model. The motor price jumps from $356 to $451 per motor and the cables are more than double the price as well, for the IP67.

I’m thinking the base model, grease, and maybe a motor cover from sheet metal might be the better option since the motors should not be directly hosed down from the little I have been around my brother’s tormach 1100 machine.

I’m sure I will have more questions come up, so should I change the title of the thread later or start a new thread, or have this thread be a build thread for my machine? I may not post a lot about my machine, but it is easier for me when I have followed along on other people’s build threads and the ongoing story of their project.

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Hi @CGT80 :wave:

Welcome to the forum and congrats on the conversion! I hope you will keep us updated with regular posts.

Hmm… you will need a brake if you don’t offload the weight of the head with gas struts or a counter weight. If cost is a factor, then just buy gas struts instead of parking it on a block of wood.

I would recommend the higher IP rating for flood coolant. However, I didn’t follow my own advice. You can 3D print top covers for the X and Y motors.

Yes, I agree.

Either way!

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Thanks for the feedback!

I went with the IP53 Clearpath servos and the 7I96S and 7I84 expansion board. The board you used is not available and they are still in the testing phase of a replacement for it and the engineer says it should be ready soon.

My mill showed up in perfect condition and I got it moved in my shop and onto my welding table, under a little track mounted hoist, which was great for lifting the motor, head, and x table off the machine. The oil lines really are a joke as they seem to expect oil to flow up into the casting for the x table, from an aluminum line just poked into the casting with not even some sealant to give it a chance. When I pumped the handle, I saw the oil squirt out of one of those holes, around the tube.

The mill looks built pretty well, but almost all of the bolts are just barely tight. Some of them don’t take any effort to remove with the short allen wrenches that came with the machine.

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Well, I don’t see a way to edit my thread title on here.

I bought an Intel NUC, almost the same as what is listed in the Dr. D-flo build sheet. Intel NUC Business Mini PC Desktop, Core i5-9300H, 8GB RAM, 256GB PCIe SSD, Thunderbolts, HDMI, RJ-45, SD Card Reader, Wi-Fi 6, Windows 11 Pro, Black - Newegg.com and I followed the directions to install Probe Basic Probe Basic APT Stable Install — ProbeBasic documentation

Through the network manager, I set the computer IP to 10.10.10.11 and the jumpers on the Mesa 7I96S to 10.10.10.10 and after searching the forums, set it to local or connected devices only, so that my wifi will work while pinging the mesa card. Linux was installed on ethernet first, per the directions, and no password was used for the root.

The ping is too high and it is an intel ethernet controller. I am able to open the text file to disable IRQ coalescing, but it is locked and read only. Others say that if you use the network manager to set the IP, not to use the terminal to enter the code that does the same.

No one seems to cover how to unlock the system files…I have searched over and over.

Linux is pretty new to me and following everything to setup linux cnc has been like trying to learn a new language. In high school, I got out of Spanish class and took photography instead and went on to get an AS degree in photography and computer information systems. I did Cisco classes in High School and used to build my own computers but hated subnet masking with IP addresses and never did programming. The hardware side was far more fun and running cat5 through buildings was something I was right at home with since I started doing construction work at age 13 and worked on customer’s homes at age 15.

Doing the copy and paste to the terminal has been easy enough, but some of the forum posts (linuxcnc forums as well) have entries without explanation and I don’t know enough about using the terminal, so they are like food recipes with only the ingredients and no instruction.

Some say to use a mesa configuration tool to make changes but I looked up the tool and the instructions are also clear as mud. It seems the tool is geared toward parallel port use with mesa, which I am not doing. I did read information from the mesa card through the terminal, so it does communicate, but I have not used their flash tool.

I have fumbled through the config part of linuxcnc to set some basics where I set the IP of the card and chose x y z axis and steps to make a config file. During that part, it lists 2 different firmware options for on board firmware for the 7I96S. One is 7I96S_7i74, the next 7I96S_d and 7I96S_dpl (can’t tell if it is letter L or i). I do have a 7I84 expansion card to add since it seemed like I would be close on inputs with just the 7I96S, but I have not connected the additional card yet. I chose 7I96S_d since it did not seem to complete setup when I chose 7I96S_7i74.

After spending days going around and around with my computer and reading the fourms, my head is just spinning and I wish my Arizonacnc kit was already here so I could focus on hardware. Also, I read that people didn’t have luck having the mesa board control the spindle speed on the PM-833, but last night I ran across direction to use the mesa boards to replace the potentiometer and direction switches on the PM mill with the spindle control on the board. The mesa can do more than just 0-10v dc control and acts as a direct replacement for the pot, if the voltage is under 20v. Any input on that would be great, if someone has tried and succeeded or failed.

The latency on this computer is still high after disabling turbo mode and a few others in the bios. The cooling is still set to control the fan speed, as it is loud at 100%, though I could set it manually to a lower percentage to test latency. I did read about configuring the processors to reduce latency, but have not tried it and don’t know exactly how to do it.

TLDR

My current goals are to:

  1. unlock the system files and disable IRQ coalescing

  2. check latency and get decent numbers (I’m still unclear on how low they actually need to be).

  3. find out the proper settings to use in pncconfig.

  4. wire my inputs and clearpath servos so that I can enter that in pncconfig and learn how to get that and the hal file right so that I can get Probe Basic to move the motors and respond to inputs.

  5. Is it a major pain to go back and change inputs, like adding a spindle encoder, after probe basic is setup? I saw there are lengthy instructions on converting one of the other gui’s to probe basic. I’m tempted to just order the same encoder that Dr. D-flo lists just to get it going right now. The power drawbar will be either priest tools or my own build, but since I don’t have a tool changer planned for now, it should not matter. I do have my current mist coolant on a solenoid and want to add flood cooling later and have a toolsetter to add air blast to.

Any help would be much appreciated,

Chris

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Hi Chris,

Sorry for the delayed response.

I use “Nano” to edit these read-only files in the terminal. Here is a quick guide.

This is not necessary.

Yes, most of the forum post skip over the easy steps because they are assumed. However for many of us building a CNC machine, this is our first foray into Linux.

I strongly recommend purchasing a new VFD. The one that comes on the mill is poor quality and not worth engineering solutions around. You can buy a 2 Hp VFD for ~$100.

Disable the Wifi and run the latency test again.

Low latency used to be critical when parallel port card were used. Now, with the ethernet cards that perform their own step generation it matters less. I would not worry about latency until you have everything up and running (including the mill). LinuxCNC will tell you if latency is an issue by throwing an error.

No - you can even edit exiting config files with the PnCconf wizard.

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Hello Chris,

I have spent the last couple of years converting the PM833-TV to CNC and have learned a lot along the way. You seem to be doing a nice job of selecting nice components. While reading your post there is one thing that comes to mind, the stock motor that comes with the mill is an odd duck. It runs at just under 7500 max rpm, is then geared down something like 2:35 to 1 to yield a max spindle sped of just about 2900 rpm. If you plan on machining aluminum with a cnc machine, this will become an immediate stumbling block. The motor will be screaming your ears off at 7400+ rpm while your spindle is running under 3000.

My suggestion is to dump the stock motor and replace with a 1.8KW or 2.6KW ac servo motor. Save the couple hundred on a new VFD and put it to the spindle servo motor, new bearings and drive pulleys. If my memory is correct, the whole deal is about $550. This will give you a conservative 5000 rpm spindle and enough torque to tap a 1/2-13 hole. It will also reduce your head weight by about 10 kg. In my humble opinion… This single improvement will make the biggest impact of any other improvement you ever do to this mill!

Best of luck… Richard

Here are a few links that discuss this further. I would be happy to share anything I have learned:

PM833 Spindle Upgrade - AC Servo vs Inverter Duty Motor - CNC Mill Conversions and Builds - Dr. D-Flo (drdflo.com)

Spindle Bearing Replacement - CNC Mill Conversions and Builds - Dr. D-Flo (drdflo.com)

PM833TV – Hot Spindle Solved – Two Oil Seals! - CNC Mill Conversions and Builds - Dr. D-Flo (drdflo.com)

Another PM-833TV Conversion - CNC Mill Conversions and Builds - Dr. D-Flo (drdflo.com)