# CNC versus manual



## GummyMonster (Feb 17, 2021)

Morning,
So I'm reading the thread on the PM-728V-T Mill, which is the one I'm planning to acquire down the road.
My thoughts right now are to set it up with full DRO's and power feeds. I have troubles with my hands,so I'm trying to minimize the manual turning/moving actions.
 Much of the other thread is about setting them up for CNC control. Most of it is waaay over my head right now.
 My question would be - what main advantages is there with CNC control over semi manual like the setup I described above. Is the CNC inherently more precise? Or is it more about the time it takes to turn out parts?
I don't need every technical reason, mainly wondering if it's something I need to consider learning, or can I make parts with the same level of precision without CNC?
Thanks for answering my many questions as a newby.
Ken


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## macardoso (Feb 17, 2021)

CNC allows you to automate your work. It does not improved the inherent accuracy of the machine. It also allows you to produce more complex geometry than would be easy to do on a manual machine. As a tradeoff, you will lose some manual functionality. You can always add jog wheels, but you'll never have the haptic feedback of "feeling" the cut through the handwheel.

I only have a CNC mill, and while it is super useful, I very much want/need a manual one as most of my work would go faster on a manual.

Get a CNC if:

You need to make a lot of the same part
Your parts have complex geometry and curves
You already work a lot in CAD and enjoy the digital workflow
You don't mind the investment and are willing to learn CAD/CAM
You don't mind the added time up front to program the machine to make your parts
Stay manual if:

Your work is lots of drilled holes and square features easy enough to make on a manual
You want to just throw your work in and get cutting
You value the "feel" of feeling the machine cut
For me, a manual mill with a DRO would cover 90% of the work I do.

CNC is awesome, but like most things it is a rabbit hole and can get expensive. It is not a must have.


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## RJSakowski (Feb 17, 2021)

I have both.  I have to say that Ido manual  more often than CNC.  The main reason is for simple jobs, it is less work to manually machine the work than to program the CNC.  I use my Tormach in a quasi manual mode, using the jog shuttle rather than turning a crank.  Kind of a macine by wire approach.  

There are times when a CNC is required.  Cutting arcs isw difficult on a manual machine unless you have an RT and even then, it can be complicated.  If you have curves that cannot  be resolved into arcs, the CNC is likely the only practical route.  Try cutting an Archimedes spiral on a manual machine. 

I bought my CNC because it enabled me to do things that I couldn't otherwise accomplish.  My driving project was making custom undercabinet lighting that had a series of elliptical curves.  I could not come up with another way to accomplish the task.


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## Reddinr (Feb 17, 2021)

I have a small CNC mill.  I got it to turn out multiples of job related parts and to turn out some tricky shapes.  I use the mill in three different ways. 

 Full CNC for multiples, bolt circles and quick shapes I can use a Gcode wizard to produce.  I almost always use CNC to cut out openings in electronic enclosures.

 Sort of CNC for drilling arrays of holes for a one or a few parts.   I write / edit some GCode to move to the multiple X-Y locations and stop.  Then I can drill and go through all the holes, then I can repeat the program for countersinking and tapping using the quill.  It results in very quick and accurate positioning.

Manual for simple milling.  It would be great to get the hepatic feedback but I've tuned my ears for what sounds and vibration are good and which are bad.  

It depends on how you think you will apply your mill.


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## ArmyDoc (Feb 17, 2021)

Another option is to get a used CNC mill with manual capability, or to do a CNC conversion of a manual mill in such a way that you preserve the manual capabilities.


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## erikmannie (Feb 17, 2021)

I like manual because I like to use my hands/eyes/mind while the cutting is occurring. I want to be as physically involved in the process as possible. A front row seat, if you will.

Having said that, I use the DROs and power feeds whenever possible. For my purposes, I am 100% satisfied with manual + DRO. The creations usually take a long time to make, though.


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## slodat (Feb 17, 2021)

I've found a fully featured, well sized manual lathe with DRO to meet my needs. When it comes to milling machines, I wouldn't give up my CNC mill for a manual machine. There's nothing I can think of doing with a manual mill that I can't do in the conversational programming on my CNC mill. All of the typical around the shop stuff is quite easy and intuitive with a control that has good conversational programming abilities. This means no CAD drawing and no CAM work. When it comes to making parts, I design in CAD and use it for the tool paths. I think what control the CNC machine has is a big factor in this conversation.


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## matthewsx (Feb 17, 2021)

I built (am building) a small CNC from various parts mostly because I wanted a mill and couldn't justify the up front cost. At this point I could have bought a fairly decent mill for what I have into this one but I wouldn't have had the learning experience.

That said, for your application I think you will be very happy with a manual mill, DRO and power feeds. You can do many operations with a DRO that would only be slightly faster full CNC, maybe slower if you count programming time. 

Again, as with everything machine related it depends on your skills, desire to learn, money, and of course what you plan on making.

I do hope to add a 3D printer eventually as well....

John


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## BGHansen (Feb 17, 2021)

I have both and use them about equally.  My Tormach 1100 is CNC, it's running a routine for a repetitive part pretty much every time I head to the shop.  I also have a Bridgeport with a circa 1981 Anilam 2-axis CNC.  The Anilam CNC keeps the handwheels so I have the best of both worlds on that machine.  That being said, since getting the Tormach the BP is 99% of the time used as a manual mill.

Macardoso has the best advice above.  It all depends on what you plan on making.  If you don't know for sure, plan on buying both.  Regardless of which one you start with, and since you've asked the question, you know you want both anyhow!

Bruce


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## DAT510 (Feb 17, 2021)

+1 on Macardoso's comments.  

I have a both a CNC mill and Manual Mill.  95% of the time I use my manual mill.  The CNC get used for one off's, that are complex shapes and curves or things that require a lot of repetitive moves, such as "Larger" deep rectangular pockets.  

This Old Tony has good video on the basics of cnc using an etch-a-sketch as an example.


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## ArmyDoc (Feb 17, 2021)

slodat said:


> I've found a fully featured, well sized manual lathe with DRO to meet my needs. When it comes to milling machines, I wouldn't give up my CNC mill for a manual machine. There's nothing I can think of doing with a manual mill that I can't do in the conversational programming on my CNC mill. All of the typical around the shop stuff is quite easy and intuitive with a control that has good conversational programming abilities. This means no CAD drawing and no CAM work. When it comes to making parts, I design in CAD and use it for the tool paths. I think what control the CNC machine has is a big factor in this conversation.


What type of machine do you have?


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## talvare (Feb 17, 2021)

macardoso said:


> As a tradeoff, you will lose some manual functionality. You can always add jog wheels, but you'll never have the haptic feedback of "feeling" the cut through the handwheel.


This really depends on the machine you purchase. I have a Bridgeport EZ Trak 2-axis CNC knee mill and it has full manual functionality. I believe there are other makes available as well. Although my mill gets used in manual mode about 90% of the time, it sure is nice to have the CNC capability when I want to make a part that is very difficult or near impossible to make manually. Just food for thought.

Ted


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## macardoso (Feb 17, 2021)

talvare said:


> This really depends on the machine you purchase. I have a Bridgeport EZ Trak 2-axis CNC knee mill and it has full manual functionality. I believe there are other makes available as well. Although my mill gets used in manual mode about 90% of the time, it sure is nice to have the CNC capability when I want to make a part that is very difficult or near impossible to make manually. Just food for thought.
> 
> Ted



That is a good point. I will condition my comment that CNC conversions done with steppers and ballscrews do not make good manual machines afterwards. Even if you leave handwheels on them the detent torque of the stepper really messes with your turning of the handwheels and the ballscrews will back drive under cutting forces.


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## dbb-the-bruce (Feb 17, 2021)

A lot of good advice here. You are likely going to want one of each dedicated. I am most interested in smaller detailed/complicated work. I have a manual mill very similar to the one you are looking at. I also have a benchtop (micro?) CNC (Carbide 3D Nomad).

The CNC is for small complicated parts that would be hard or impossible to do by hand on a manual mill. I went with DRO on the mill and it has a number features (hole patterns, saved points, centering) that I would really miss if I didn't have them. I did originally consider a CNC conversion for my mill but quickly realized that I'd end up wanting a manual mill to go with it. As others have pointed out, once you switch to ball screw feeds manual cranking is hard or impossible. Another consideration (at least for me) is that spindle speeds on a converted-to-CNC mill are likely to be limited to lower than you want for CNC. Typical CNC spindle speeds are 8-20K with the smaller bits used on small CNC mills.

My Nomad is great for small brass parts and has been a great machine for me to learn with. They have just upgraded it with more spindle power and speed. At this point if/when I get another CNC I'd be looking for both power and spindle speed and probably a used machine engineered for CNC, not a conversion.

This is all based on the kind of work I want to do and my experience so far.

If you are just getting started, go with a manual mill and plan on dedicated CNC later. If you want to learn CNC and are happy with small stuff, there are a few good bench top machines under $4K.


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## slodat (Feb 17, 2021)

ArmyDoc said:


> What type of machine do you have?



Lathe is an American Pacemaker 14x30 with 15hp spindle. Mill is a Tree J425 with DMM AC servos and Centroid Acorn. I'm also doing a similar retrofit on a Hardinge lathe with Accuslide CNC conversion.


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## talvare (Feb 17, 2021)

macardoso said:


> That is a good point. I will condition my comment that CNC conversions done with steppers and ballscrews do not make good manual machines afterwards. Even if you leave handwheels on them the detent torque of the stepper really messes with your turning of the handwheels and the ballscrews will back drive under cutting forces.





dbb-the-bruce said:


> As others have pointed out, once you switch to ball screw feeds manual cranking is hard or impossible.


These comments kind of puzzle me. The only CNC mill I have operated is the one I own, so I'm not doubting that these things happen. But, my mill doesn't display any of these characteristics. The handles operate smooth as silk and they are directly coupled to the ball screws. I routinely climb mill while in manual mode and have never experienced any adverse machining. Just kind of wondering what makes some CNC machines act differently.
Ted


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## GummyMonster (Feb 18, 2021)

Lots of great advice here.
Thank you.
 I'll definitely be staying with the manual setup with DRO's and power feeds.
 I can't really see many projects I'd be making that would justify the features CNC excels at.
I can put the money into more tooling.
I've always been a "hands on" type, and my one finger typing skills would make coding and such awfully slow .
My wife wants to be involved, but making different pieces steadily would make her nervous. So if I need to repeat a piece in volume, 
She can handle that while I work at other tasks.
 She'll be my own little CNC machine! And with minimal typing too !
Ken


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## ArmyDoc (Feb 18, 2021)

GummyMonster said:


> Lots of great advice here.
> Thank you.
> I'll definitely be staying with the manual setup with DRO's and power feeds.
> I can't really see many projects I'd be making that would justify the features CNC excels at.
> ...


Conversational milling, as I understand it, alleviates alot of the typing.  Basically it automates repetative tasks, such as bolt holes for example.  Set your zero, enter the diameter and pattern of the bold holes, and it drills all of them.  No figuring out the coordinates for each hole, or even having to move it to the coordinates if you have a DRO that calculates it for you.


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## Aaron_W (Feb 18, 2021)

I'm not a CNC guy but, there are some less expensive entry points that could be useful and help you evaluate how seriously you want to get into that hole. There are a few ready to go mini-cnc lathes and mills in the $2500-4000 range, Taig and Sherline being well known. They are small but capable, with a lot of options. They could be useful for making small parts in quantity, screws, mounting blocks, grip panels etc. 

Cheaper are the CNC router / engravers which are typically limited to wood, plastic and soft metals like brass and aluminum. These can be cheaper than mini-CNC mills or for similar money you can get a bigger one.

The third is laser cutters / engravers. These would be more useful for decorative items, tags, trim pieces etc.

Last and cheapest are the 3D printers.

Other than the mini-mills these are not direct comparisons to a CNC mill, but all are CNC machines so would help develop your skills, and give you a better idea if this is something you want to pursue. The other machines could also open up some other potential business opportunities, making custom plaques, engraving tags etc.


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