What type of machine do you have?
-
Welcome back Guest! Did you know you can mentor other members here at H-M? If not, please check out our Relaunch of Hobby Machinist Mentoring Program!
CNC versus manual
- Thread starter GummyMonster
- Start date
- Joined
- Apr 4, 2016
- Messages
- 959
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
- Joined
- Mar 26, 2018
- Messages
- 2,725
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.
- Joined
- Feb 28, 2019
- Messages
- 530
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.
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.
- Joined
- Jan 20, 2021
- Messages
- 296
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.
- Joined
- Apr 4, 2016
- Messages
- 959
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
- Joined
- Feb 12, 2021
- Messages
- 34
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
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
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.
- Joined
- Nov 14, 2016
- Messages
- 3,291
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.
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.