If you were to get a mill and convert it to CNC, what would you get?

[automatedingenuities]

That often makes things difficult. You may have to use linear encoders so the motors can track the positions, and you would have to disengage the motors to move the machines manually. Some steppers motors have dual shafts so you can drive the motors with a handwheel, but the motor would still be required to be disengaged and unless the motors have built in encoders you will have to add some.

What alot of people do instead is they use conversational programming or use a pendant. You can think of CNC like power feeds on all axis of a milling machine, the CNC ability makes it much easier and accurate, plus you effectively have the DRO for the positions.

In my opinion it would be worth it to learn conversational programming for the simple jobs or use a pendant or even learn a bit of gcode so you can make the machine do what you want versus keeping the hand and jog wheels.

This is easily handled with an AllIn1DC or Oak and servos - no additional encoders needed. Just push a button on the operator interface to disable the motors and you can crank the handles all you want with the same manual feedback of the original machine.

While I agree that everyone should learn G-Code and Intercon, MANY things are much faster with manual operations. I challenge anyone to face off a saw cut end on a piece of stock using g-Code, Intercon, or pendant faster than I can do it using the handwheels on my machine.
PXL_20231201_003752378.jpg

Beautiful machines you got there. You are absolutely right, using handwheels are much faster for some operations. Can be done with a pendant like you mention but still requires a level of programming, as you still will need to set the feedrate or adjust the mode so the axis moves how you envision it.

Yes definitely doable with allin1dc or oak, and I should have mentioned that.

The unfortunate thing is somewhere it's tradeoffs. Typically linear rails machines don't have handwheel control, dovetails machine are slower and don't do 3d machining as well...

[kb58]

Oh I completely agree on how long it takes to do a simple operation. Right now I'm diving into learning the entire workflow from CAD to CAM to feeding the machine. What I'm trying to make would have been done many weeks ago had I just used the manual mill, but I'm in this to learn. CNC is brilliant for making multiple copies of things, but for making one of something, especially something that needs only simple inexact operations, not so much.

[suntravel]

Oh I completely agree on how long it takes to do a simple operation. Right now I'm diving into learning the entire workflow from CAD to CAM to feeding the machine. What I'm trying to make would have been done many weeks ago had I just used the manual mill, but I'm in this to learn. CNC is brilliant for making multiple copies of things, but for making one of something, especially something that needs only simple inexact operations, not so much.

I am faster with CNC for everything that needs more than one move, even facing in 3 passes is faster with Intercon than a manual operation for me

[WesM]

Kinda depends on what you want to do with the machine. What kind of tolerances do you need to hold? Will it be running all the time, or just light hobby use?

Precision Mathews has a few models and is a popular hobby level machine.

A bit more than hobby use, a lot less than commercial. Don't need extraordinary precision.

I am currently working on a retrofit for my 1987 cnc knee mill. Back in the day these were the top of the line industrial machines, so they tend to have nice features, like ground ballscrews, 30 or 40 taper spindles, power drawbar and weight 3k-5k lbs. In my opinion these older cnc knee/bed mills tend to be far and away better then the precision mathews, or even hobby level VMCs like Tormach.

Now most shops wont even look at the old cnc mills, so the get sent to the junk yards, or sold off for nearly scrap weight (or in my case given away for free). If you can find them in mechanically good condition they can make great retrofit candidates.

Depending on how involved you want to get, Centroid does sell complete retrofit kits for these types of machines, you typically would not touch the mechanicals, all you would do is mount the new ac servos and plug them into the control from centroid. Some wiring would be required for the spindle motor, lube pump etc, but it seems pretty straight forward.

[EastMemphis]

I am currently working on a retrofit for my 1987 cnc knee mill. Back in the day these were the top of the line industrial machines, so they tend to have nice features, like ground ballscrews, 30 or 40 taper spindles, power drawbar and weight 3k-5k lbs. In my opinion these older cnc knee/bed mills tend to be far and away better then the precision mathews, or even hobby level VMCs like Tormach.

Now most shops wont even look at the old cnc mills, so the get sent to the junk yards, or sold off for nearly scrap weight (or in my case given away for free). If you can find them in mechanically good condition they can make great retrofit candidates.

Depending on how involved you want to get, Centroid does sell complete retrofit kits for these types of machines, you typically would not touch the mechanicals, all you would do is mount the new ac servos and plug them into the control from centroid. Some wiring would be required for the spindle motor, lube pump etc, but it seems pretty straight forward.

I'd love to retrofit an older quality machine but I lack knowledge of anything to do with them so I would be started out at zero. I can't tell if a machine is good or worn out. I can't tell if the components are quality, hacked, destroyed, or serviceable. So unless someone was doing the picking for me, I can't go that route.

The PM 940 route seems to be a good path. The machine may not be the best in the world but it's new so should function as expected. The CNC kits for the PM 940 appear to be mature and available, another plus, and they have technical support.

I'm not looking for the ultimate CNC mill. I'm looking for one that I can use to make parts out of steel. Right now, the PM 940 / Arizona CNC path looks pretty bright. I have to wait until the next tax year to buy one so I still have some time to decide.

[Muzzer]

CNC is brilliant for making multiple copies of things, but for making one of something, especially something that needs only simple inexact operations, not so much.

There are many parts you simply couldn't make on a manual machine, even as a one-off. Placing features precisely and without error, creating curved and organic surfaces, roughing out surfaces rapidly with adaptive toolpaths, chamfering complex edges and finessing dimensions with tool wear compensation etc are pretty much beyond manual operations.

As an example, imagine trying to complete this part on the first attempt:

And yes, there are quite a few operations where I place holes, face off stock, measure features (using the probing operations) etc quickly and accurately without either Fusion CAM or conversational. These are more accurate and consistent than using a conventional DRO.

[WesM]

I am currently working on a retrofit for my 1987 cnc knee mill. Back in the day these were the top of the line industrial machines, so they tend to have nice features, like ground ballscrews, 30 or 40 taper spindles, power drawbar and weight 3k-5k lbs. In my opinion these older cnc knee/bed mills tend to be far and away better then the precision mathews, or even hobby level VMCs like Tormach.

Now most shops wont even look at the old cnc mills, so the get sent to the junk yards, or sold off for nearly scrap weight (or in my case given away for free). If you can find them in mechanically good condition they can make great retrofit candidates.

Depending on how involved you want to get, Centroid does sell complete retrofit kits for these types of machines, you typically would not touch the mechanicals, all you would do is mount the new ac servos and plug them into the control from centroid. Some wiring would be required for the spindle motor, lube pump etc, but it seems pretty straight forward.

I'd love to retrofit an older quality machine but I lack knowledge of anything to do with them so I would be started out at zero. I can't tell if a machine is good or worn out. I can't tell if the components are quality, hacked, destroyed, or serviceable. So unless someone was doing the picking for me, I can't go that route.

The PM 940 route seems to be a good path. The machine may not be the best in the world but it's new so should function as expected. The CNC kits for the PM 940 appear to be mature and available, another plus, and they have technical support.

I'm not looking for the ultimate CNC mill. I'm looking for one that I can use to make parts out of steel. Right now, the PM 940 / Arizona CNC path looks pretty bright. I have to wait until the next tax year to buy one so I still have some time to decide.

Most mills, even the hobby ones can cut steel, its just a matter of how fast and what kind of finish you can get. The PM 940 seems like a decent mill for someone just getting into machining. I always struggled with the idea of gutting a brand new machine to make it into something else. I wish PM would sell those machines preconfigured with ballscrews. I would recommend getting one of the models with hardened ways, CNC tends to put more wear and tear on the ways then manual machining.

the Dr D-flo channel on youtube has a nice overview of the conversion process for a PM machine. He used linux CNC, but the process for centroid should be similar.

[EastMemphis]

I think the PM 940V and Arizona CNC will work together well. The next thing is the controller. Any recommendations on that? I'd like to purchase a "box" with everything in it. Who is good at building controller boxes for mills?

Thanks all for the comments on this thread.

[cnckeith]

I think the PM 940V and Arizona CNC will work together well. The next thing is the controller. Any recommendations on that? I'd like to purchase a "box" with everything in it. Who is good at building controller boxes for mills?

Thanks all for the comments on this thread.

gary campbell builds turn key cnc control boxes!