Would You Upgrade To A Larger Mill Or Cnc Current Mill?

[shooter123456]

Hi everyone. I am new to the forum so I thought I would introduce myself. I am 20 years old and I am pretty new to machining. I have had a Harbor Freight mini mill for almost 6 months now and I have at least 100 hours using it. I work mostly with aluminum but I have done a little bit with 303 stainless. With my mill I have completed several 80% AR lowers, fixed 2 that I did with my drill press, made a chassis for one of my rifles, made a few muzzle brakes, and an AR gas block. I am just a hobbiest and I don't plan to use the machine to make any money. The chassis really pushed the capabilities of the mill and I have to stop and move the workpiece or the vise to machine the whole thing. This was very slow and certainly led to some accuracy problems.

Anyway, onto my question. I am not sure which way I want to take my hobby at this point. I have some extra money from my tax refund and I was looking at either getting a larger benchtop mill or converting my current mill to CNC. I feel like I will end up upgrading eventually but I also think CNCing would both be very interesting and keep me busy for a long while. I would like to machine an AR upper and lower from billet stock as well as reverse engineer a glock slide. I have plans to design and machine another chassis as well, but that will give me the same problems as the last one I did.

I currently have a 3 axis DRO and belt drive installed. If I upgrade I will sell this mill.

Has anyone been in the same position? I have never used a CNC machine or a larger mill so I am not sure which would benefit me better.

Edit: A few things I forgot: I currently have a 7x12 HF lathe as well that has been serving me well. I am not looking for a new one at this time. I would also love to get a used bridgeport style mill but I am very limited in space. Maybe when I have my own house with a shop attached I can get one but that is a long ways off.

 

[Billh50]

shooter,
as you progress you will want something more than you have now as far as size. I myself would love to just have a real mill because I am stuck using a drill press with cross slide as a mill. So if you can afford it now, try to get something that will fill the bill for doing what you plan on making.

 

[shooter123456]

shooter,
as you progress you will want something more than you have now as far as size. I myself would love to just have a real mill because I am stuck using a drill press with cross slide as a mill. So if you can afford it now, try to get something that will fill the bill for doing what you plan on making.

Thats what I was figuring. I got the mini mill because I didn't want to invest a fortune and find out that I don't like machining. At this point I am confident that I enjoy it will for years to come. But I have found that the cost to CNC goes up significantly as the machine gets larger so it would be a long time before I could afford to CNC a larger mill.

 

[RCWorks]

I'd go to a bigger mill as adding CNC is no big deal. Bigger mills have more going for them other than the size of the table.

 

[metastable]

Hi,
Going CNC would increase your capabilities and repeatability in the same envelop while going big would give you a bigger envelope and more rigidity allowing you to be more agressive. I personally think CNC machining is fairly different than manual machining even though one is the continuation of the other and underlying technology is the same.

I think you are the only person who can answer your question. Ideally best way to go is to go to bigger CNC. Like RCWorks said it is only marginally harder and marginally more expensive to Mach3 a bridgeport. But personally I'd go CNC first for the improved capability.

Here is my two cents.

Going CNC:
Pros:
Ability to do more in a single setup (Angular cuts, Curvature cuts, which require a new setup in manual world)
Adaptive clearing
Engraving
3D milling (practically impossible with manual milling)
Rigid tapping (maybe)
Program once, machine multiple times.
Easy to take apart, fix, improve.

Cons:
Can be a burden for on-off parts, simple operations. You have to plan all the details in advance.
Steep learning curve for the conversion. You'll end up learning a lot about electronics, motion control etc...
Steep learning cure for software. You'll need a 3D modelling software, a CAM software and a post processor. Fusion 360 is a good option for all 3 needs with a good price.
You'll be crashing and maybe damaging the machine and will need to learn how to fix it.

Going big:
Pros:
Bigger work envelope
Mountains of torque (compared to a mini-mill)
Rigid machine -> better surface finish / more agressive cuts
Practical. Don't have to plan anything. You can design parts or make changes as you go along. (Might not be a good idea but possible)

Cons:
Need more space
Might need 3 phase
Parts are more expensive
Might need some sort of lift to fix or restore the machine since the parts will be heavy.

 

[Bluedog]

I started with a mini mill also and soon cnc'd it. I quickly found that I wanted a larger mill, so I bought a Wells Index knee mill and it makes the mini mill seem like a toy. I know that great work can be done on a mini mill but the difference is amazing. All the cnc gets used for these days is engraving. I will revisit cnc someday, but it will be with a larger machine. I also believe I have learned a lot more about machining using the manual vs using the cnc so soon. I understand the space and cost issues but my advice would be to get the largest manual mill you can now and go cnc later. I actually have less money in my knee mill than I do in the cnc mini mill. Hopefully your mini has a r8 taper so you could upsize and still use most of your tooling.

 

[higgite]

....
I have plans to design and machine another chassis as well, but that will give me the same problems as the last one I did.
.....

I'm not a CNCer, so I may be speaking out of turn, but that statement alone would push me toward upgrading.

Tom

 

[TomS]

Hi,
Going CNC would increase your capabilities and repeatability in the same envelop while going big would give you a bigger envelope and more rigidity allowing you to be more agressive. I personally think CNC machining is fairly different than manual machining even though one is the continuation of the other and underlying technology is the same.

I think you are the only person who can answer your question. Ideally best way to go is to go to bigger CNC. Like RCWorks said it is only marginally harder and marginally more expensive to Mach3 a bridgeport. But personally I'd go CNC first for the improved capability.

Here is my two cents.

Going CNC:
Pros:
Ability to do more in a single setup (Angular cuts, Curvature cuts, which require a new setup in manual world)
Adaptive clearing
Engraving
3D milling (practically impossible with manual milling)
Rigid tapping (maybe)
Program once, machine multiple times.
Easy to take apart, fix, improve.

Cons:
Can be a burden for on-off parts, simple operations. You have to plan all the details in advance.
Steep learning curve for the conversion. You'll end up learning a lot about electronics, motion control etc...
Steep learning cure for software. You'll need a 3D modelling software, a CAM software and a post processor. Fusion 360 is a good option for all 3 needs with a good price.
You'll be crashing and maybe damaging the machine and will need to learn how to fix it.

Going big:
Pros:
Bigger work envelope
Mountains of torque (compared to a mini-mill)
Rigid machine -> better surface finish / more agressive cuts
Practical. Don't have to plan anything. You can design parts or make changes as you go along. (Might not be a good idea but possible)

Cons:
Need more space
Might need 3 phase
Parts are more expensive
Might need some sort of lift to fix or restore the machine since the parts will be heavy.

I would go with a bigger mill then CNC it when you are ready. You won't regret having a larger work envelope, and the rigidity.

IMO the steep learning curve for the conversion and software should be in the CNC Pro's category. Learning something new should never be a Con.

I went through the same process about 2 years ago. Not having much experience with electronics nor the associated software I bought a benchtop mill and converted it. Looking back on it was one of the most satisfying machining experiences I've had. I would do it again in a heart beat. Actually I'm thinking about converting a lathe. This is addicting.

Tom S.

 

[USNFC]

I too would go bigger. I started on an import mill/drill, then went to a Rockwell, then to a millrite. Each step seemed like an exponential improvement. I use a b'port at work, but it's honestly not any more capable than my millrite. I would bet a 10X54 would be though. I am biased though because I don't own a cnc. I used a large one at my last job, but still spent more time on a manual Acer.

 

[Groundhog]

I too started with a mini-mill. A few years later I found a small used CNC mill (Syil X4+) and have used it for 5 years or so. I am self taught (videos, books & internet). Having had a better machining background, education or mentor might have changed my following experiences.
I agree with a previous post that manual milling teaches you a lot more than CNC milling. Even though a CNC can be like a manual mill with power feeds and DROs, you don't get the hands-on input that you get from turning knobs. That input tells you a lot about the forces involved. When those forces are pushed with a manual mill you soon learn to back off. When they are pushed with a CNC you break stuff. I spent a lot of money on broken tooling and ruined parts finding the limits of my CNC.
If I had it to do over again I would go with a larger manual mill (Bridgeport sized) and later go to CNC (modifying the Bridgeport or trading for a purpose built CNC. The only exception to this would be if I could afford a larger CNC and felt I had ample manual milling experience.