Where to next?

[macardoso]

I agree on the Bridgeport, however if you want to stick with a benchtop machine, the PM940 looks to be an awesome candidate.

If you are annoyed with Mach 3, just take the plunge and get Mach 4. I was a huge Mach 3 fanboy and I have never looked back.

Depending on you needs (hobby vs production work) consider looking for some higher end servo controls. AB Ultra 3000 drives and the Delta A2 drives are really solid. They can be found used (and in great condition) quite cheaply. If you like new, I would go with DMM as well. There are quite a few people here that have experience in control and CNC panels, so ask questions and you will get answers!

Mike

 

[bakrch]

I agree on the Bridgeport, however if you want to stick with a benchtop machine, the PM940 looks to be an awesome candidate.

If you are annoyed with Mach 3, just take the plunge and get Mach 4. I was a huge Mach 3 fanboy and I have never looked back.

Depending on you needs (hobby vs production work) consider looking for some higher end servo controls. AB Ultra 3000 drives and the Delta A2 drives are really solid. They can be found used (and in great condition) quite cheaply. If you like new, I would go with DMM as well. There are quite a few people here that have experience in control and CNC panels, so ask questions and you will get answers!

Mike

I generally like new stuff, so I would go with DMM it seems based on recommendations. I will have to look into the used options you listed though, as I am unfamiliar. Used is certainly not out of the question.

I can live with most Mach 3 issues, it really is decent for most things ... but cannot get the 4th axis to feed predictably in any of the modes. I know the posted code is good as I have a Haas and Doosan at work that run smoothly with the same code (using either the Mach 3 post or Fanuc). But for some reason, the "use radius as feedrate" function does not work for me on my setup. The problem seems to appear only when A runs simultaneously with another axis. A by itself is no problem. I've read everything that can be found, gone over my settings ... so unless it's a motor tuning issue that is beyond my understanding there seems to be no hope for me. Have just been getting by with using the "set maximum feed" feature though Cimco Edit.

Mach 4 industrial would be great, Macro B in the home shop would be super handy. The price tag for that is a bit high, especially when I can just translate a macro to G-code through NC Plot software. Hobby Mach 4, eh ... I just do not trust it based on what I have read.

The 940M certainly does have my attention still, that thing is an absolute unit! I suppose I just need feedback from current owners as to whether the quality of the base machine is worth it. Reading through posts here I did find an owner that wishes he started with the 833T.

I would rather not lug around a 1 ton knee mill, but quality of machine is more important to me than ease of moving it around.

 

[bakrch]

Oh, and this would not be a production machine ... more of a hobby type thing with an accuracy/repeatability that can be trusted.

 

[macardoso]

My biggest complaint with doing a CNC conversion is the spindle. You either get stuck with a manual machine with a 3000 rpm (more or less) spindle, or you end up with one of those HF spindles that does 24000 rpm with no torque or rigidity or a large taper.

I have yet to find a spindle option that gives you 8-10k with appreciable torque, a large taper, ATC or drawbar options, spindle feedback, etc.

I did a custom job on my G0704 CNC spindle. I ended up with 2.5HP and 5000rpm but it is still limited for real CNC work.

Larger machines use larger cutters and are less demanding on spindle speed, but you still want the capability to use small cutters effectively.

I really respect the engineers who design those 40k rpm HSK spindles on some of the newer machines. Crazy speed, crazy precision, and can still drive a 1 inch tap without issue.

 

[macardoso]

Here is a build thread to my control panel on my G0704. Gives you an idea of what a system with AC servos might look like. I'll admit this is tremendously overpowered and complicated for this small machine, but it is sized to be moved onto a much larger machine like a PM940 once I buy a house. Maybe some of the info would be of help to you.

G0704 CNC AC Servo Rebuild (Picture Heavy)

Hi All, About 5 years ago I completed a CNC conversion of a Grizzly G0704 milling machine. Like everyone at that time I chose to go with the Hoss Machine style conversion as there were not many options on the market. I was not comfortable designing my own system at the time since I was just...

www.hobby-machinist.com

 

[JimDawson]

Excellent! Thank you for the information, this is looking like a great option if I can find 3-axis.

My pleasure

I saw your Z-axis conversion on yours, amazing!

Thank you

Not that I am even ready, but I found this one on ebay this morning.

EAGLE CNC VERTICAL MILL 10" X 54" 11190940010 | eBay

Find many great new & used options and get the best deals for EAGLE CNC VERTICAL MILL 10" X 54" 11190940010 at the best online prices at eBay! Free shipping for many products!

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Yup, there are a few around. I'm guessing if you walked in the door with about $1500 cash that you could drag it home. That looks like the heavier 4VK frame with square ways. Same machine I have.

Some concrete work, a drop deck trailer, and HF gantry crane would easily get me into this project. Even if I have to pay for freight when the time comes it doesn't look like it would be a budget buster.

Not sure if the HF gantry is going to lift that. It's about a 3500 lb machine. But a rented pallet jack would work well, except that your floor is a bit rough to roll a pallet jack. A 5000lb short mast forklift with pneumatic tires would be the best option.

 

[bakrch]

My biggest complaint with doing a CNC conversion is the spindle. You either get stuck with a manual machine with a 3000 rpm (more or less) spindle, or you end up with one of those HF spindles that does 24000 rpm with no torque or rigidity or a large taper.

I have yet to find a spindle option that gives you 8-10k with appreciable torque, a large taper, ATC or drawbar options, spindle feedback, etc.

I did a custom job on my G0704 CNC spindle. I ended up with 2.5HP and 5000rpm but it is still limited for real CNC work.

Larger machines use larger cutters and are less demanding on spindle speed, but you still want the capability to use small cutters effectively.

I really respect the engineers who design those 40k rpm HSK spindles on some of the newer machines. Crazy speed, crazy precision, and can still drive a 1 inch tap without issue.

I hear you. I do a lot of engraving in Ti and SS at home, 2500 rpms have been killing me for that. 10k would be sweet, but 5000RPM and 2-2.5HP would be a great compromise to cover my basic needs.

The floppy column on this size machine affects me with 1hp @ 2500RPM, can't imagine how much more of an issue that is for you now.

Here is a build thread to my control panel on my G0704. Gives you an idea of what a system with AC servos might look like. I'll admit this is tremendously overpowered and complicated for this small machine, but it is sized to be moved onto a much larger machine like a PM940 once I buy a house. Maybe some of the info would be of help to you.

G0704 CNC AC Servo Rebuild (Picture Heavy)

Hi All, About 5 years ago I completed a CNC conversion of a Grizzly G0704 milling machine. Like everyone at that time I chose to go with the Hoss Machine style conversion as there were not many options on the market. I was not comfortable designing my own system at the time since I was just...

www.hobby-machinist.com

I am very familiar with your thread and have read through it a few times. Much of that is well over my head so I just have been watching in silence.

Not sure if the HF gantry is going to lift that. It's about a 3500 lb machine. But a rented pallet jack would work well, except that your floor is a bit rough to roll a pallet jack. A 5000lb short mast forklift with pneumatic tires would be the best option.

Ha, oh jeez ... just assumed it would be around 2k. Having a closer look it does look a bit thick. I have had my share of pallet jack failures on that floor. Getting the PM1236 crate into my garage was fun (not). Ended up having to push it the last bit in with my truck just so the door could be closed.

 

[macardoso]

The floppy column on this size machine affects me with 1hp @ 2500RPM, can't imagine how much more of an issue that is for you now.

Honestly, the rigidity is my killer. Really the reason I want to upgrade to a bigger machine. For the most part, the torque and power of the spindle only get used when roughing or using large drills. I've done some cutting on this machine I never would have thought was possible. When I'm machining aluminum, every tool gets set to 5000rpm since I would be programming them much faster if I had the spindle speed.

I program with the rigidity issues in mind, so typically very deep depths of cut with very small step overs (dynamic toolpaths from MasterCAM). I can get a bit aggressive during roughing, but need to finishing passes very slowly otherwise the machine just bends around and can't keep tolerances.

I am very familiar with your thread and have read through it a few times. Much of that is well over my head so I just have been watching in silence.

Whoops I've come to accept that I like working on the machine itself more than making parts on it. That page is just a good way for me to keep track and look back on what I've done with the thing. I really need to get some projects to build on it!

 

[bakrch]

Honestly, the rigidity is my killer. Really the reason I want to upgrade to a bigger machine. For the most part, the torque and power of the spindle only get used when roughing or using large drills. I've done some cutting on this machine I never would have thought was possible. When I'm machining aluminum, every tool gets set to 5000rpm since I would be programming them much faster if I had the spindle speed.

I program with the rigidity issues in mind, so typically very deep depths of cut with very small step overs (dynamic toolpaths from MasterCAM). I can get a bit aggressive during roughing, but need to finishing passes very slowly otherwise the machine just bends around and can't keep tolerances.



Whoops I've come to accept that I like working on the machine itself more than making parts on it. That page is just a good way for me to keep track and look back on what I've done with the thing. I really need to get some projects to build on it!

Honestly though, it's a good thing. Watching you, @shooter123456 and @spumco doing your thing is largely what has inspired me to begin learning the bits I am weak on. It will take a few years to get where I need to be on the control/electrical end ... but I am certainly hooked.

I can design parts and machine them all day, been doing that for 25 years now ... time for something new!

 

[bakrch]

The DMM kits are looking quite reasonable.

Since a new machine is not 100% decided upon yet, I can just sit here and wait for a deal than I cannot be passed up.

The 750w DMM kit utilizes Nema 34 mounts, which would obviously work for a larger machine when the time comes. There is no reason why I should wait to build the control. All it would take is new motor mounts to get this onto my PM25, so that is looking quite attractive as a first step.

The 1.8kW DMM motor looks good for the spindle, but I am unsure of the pros/cons in driving that with a VFD or using one of their drives? AC bearings are already in my possession, but that was more as a precaution just in case the originals failed. This motor is rated for 1500RPM, is it unreasonable to count on the maximum 3000RPM to net me 6k via 2:1 pulley system?

I do have a spare 2HP motor as my PM1236 was upgraded to a Baldor, but that looks like too much trouble to adapt to a mill configuration.