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VMC vs CNC Knee Mills

Well then... That's easy.. Why didn't you say so in the first place??

Don't buy a freaking knee mill.
I don't want a knee mill. I want a cnc knee mill 🤣. Obviously I'm limited to single phase machines (I don't want to deal with phase converters), and I'm limited to machines shorter than 9ft. Other than that, the options are endless. I would prefer a bed mill over a knee mill, and that's about all I know 🙄
 
I don't want a knee mill. I want a cnc knee mill 🤣. Obviously I'm limited to single phase machines (I don't want to deal with phase converters), and I'm limited to machines shorter than 9ft. Other than that, the options are endless. I would prefer a bed mill over a knee mill, and that's about all I know 🙄

You haven't been there yet.. What you want now is not what you will want in the future..

In the future, you will want an ENCLOSED machine, and a TOOL CHANGER..

You will be begging for them, and hating yourself for not going in that direction in
the first place..

YOU.. Will literally HATE yourself. I guarantee that.

Tons of machines can fit under a 9 foot door.. The 3 phase thing.. I guess if you
can buy a 5hp wet-dry-vac that plugs into a 15amp 120 outlet, then you should be
OK..
 
My two cents, look at something like this:

does both manual and simple CNC work, great for protype and gunsmith repair parts.

if you are wanting to go into CNC production parts, then yes, get a VMC machine.
 
Bobw is 100% right. I went the CNC knee mill route to start, yeah it worked for a while until I could upgrade, but a VMC is so many light years ahead that the knee milll was an unnecessary stepping stone.

We still have a manual Excello knee mill in the corner, and sure it's handy to knock a slot in something, but that's not where the money is made. I don't regret selling the CNC knee mill for a second, there is not a single thing that it would do better than the VMC's.
 
My two cents, look at something like this:

does both manual and simple CNC work, great for protype and gunsmith repair parts.

if you are wanting to go into CNC production parts, then yes, get a VMC machine.
I was looking at a used prototrak, actually. It's a 2007 model for $22k. I figured I could get something like that to start with, along with a lathe, and move into a VMC. Or... buy the best vmc I can with my budget.

Honestly I have no idea where the wind will take me, so its probably not a huge deal what i choose. I could start with either setup and be successful (or not)
 
My two cents, look at something like this:

does both manual and simple CNC work, great for protype and gunsmith repair parts.

if you are wanting to go into CNC production parts, then yes, get a VMC machine.
Robin Renzetti uses one of those to achieve impressive results, but the hoops he jumps through make me love having a tool changer.
 
Ran a knee Milltronics Partner 4 at work.

Hand tool changes are a pain, but if you keep your brain working, you can plan around pretty decent runs time-wise, between them. I used to program an operation, get it running, and while It was running, sit down and program the next op. Made a lot of good parts that way. Progress started being made, really quickly, and the boss was (usually) happy. Used a lot of 3/8 and smaller end mills, and let the programming beaver away at the work, instead of relying on brute force and big machinery. Got there in the end. Pretty much a matter of having to learn to make the best of what tools you have available.

If you do go with a knee type cnc, get one with the whole head traveling up and down. Much less dicking around, than having to live with a maximum of whatever the spindle travel is, as your work envelope. Had a little over 5 inches Z travel on the Milltronics, and had to get used to putting long tools in short holders, etc., to make best use of a set of tools as needed.

Tooling. Buy what you need, when you need it. I had lots of tooling that was new, never been used, in the shop, that someone thought we needed, but really didn't. You can't stock one of everything, even on NASA's budgets, but you can order and have almost anything, for first thing tomorrow! Face it, you are not going to start off programming parts that need 20+ tools in the tool changer. Buy as you need or can afford.
 
Hi guys (and gals),

New here to practical machinist. I'm a long time fabricator and aircraft structures guy, and I'm getting into the world of machining. To make it better (or worse), I'm starting a garage shop. I don't have to capitol or space to aquire the types of VMC's that I would like, so I'm wondering if going with a CNC knee mill is a good alternative (at least to start with)?

I plan on running as a job shop (repairs, prototype, small runs, etc.), and I will also have a 14x40 lathe, so I'm wondering where the best bang for my buck is as a start up shop.

I've looked at everything from Haas mini mill and TM1, various cnc knee mills and even tormach. While I certainly want the ease of use with a VMC, I think a cnc knee mill might be more versatile in a small shop (I think?).

I'm also diving into the world of gunsmithing, so a knee mill makes sense for this type of work. However, there are a lot of uses for a VMC as well with consideration to custom machining and engraving.

Given I don't have to funds to purchase a VMC and knee mill, which one would you pick? And apologies up-front if this is a beat up topic. I couldn't find anything useful other than the "haas vs tormach" debate.
You should consider my Tree Journeyman 325. Dynapath 3 axis control, 40 taper. In very good condition. Yes you still have to change tools by hand, careful programming can ease the pain. About the same size as a Bridgeport, weighs about twice as much. No tilt or nod, no sliding ram or swivel so it is MUCH stiffer than the normal knee mill. I will include the tooth belt and pulleys to get 7500 rpm out of the spindle. It will come with 6 tool holders. I have more holders at extra cost. Although Tree is gone parts are available. Dynapath is still around and supports the control. 5000.00
 
Lots of things aren't worth setting up on a CNC to do a simple operation

I love it when people say this,because 9 times out of 10 they don't know what they're talking about.
Usually when they say this they have a shitty BP clone as their daily driver that is slower than molasses in January that the cnc will outperform in every single regard.
Setting it up in a cnc is no different than setting it up on a BP. Unless off course you need to hang the part off the table.
 
How about something like this, listed at $14,500 "asking price".
Apparently very "easy" Mazatrol M plus programming.


Yes you'll need a few Cat 40 toolholders, some EM collets and holders.
How many tools would you really need for any particular job ?
Maybe 4 or 5 to drill and tap; maybe 2,3 or 4 endmills ?
A decent vice, or 2 when the time comes.
You'll need to buy the actual tools (bits) whatever machine you buy, maybe the same number of Cat 40 or R8 toll holders.
One feature of a BP that's hard to replicate is the tilting head. This can be achieved on a VMC with creative use of tool bits, and some form of tilting device to hold the vice, or custom made jaws.
I think you'd be a lot further ahead. Maybe a slightly longer learning curve up front, but a lot more capacity for the future.
Bob
 
I don't want a knee mill. I want a cnc knee mill 🤣. Obviously I'm limited to single phase machines (I don't want to deal with phase converters), and I'm limited to machines shorter than 9ft. Other than that, the options are endless. I would prefer a bed mill over a knee mill, and that's about all I know 🙄

Single phase machines are not really a thing. You can run a 3-5 HP spindle motor using a vfd on single phase 220v though.

I would suggest starting with your shop space, not machines. If it has not been done yet; insulate the space, update the wiring, add outlets everywhere, finish the walls and update the lighting. This is far easier to do now without 8 tons of stuff in the way.

After that, I would look into a phase perfect digital phase converter; 20hp if you've only got 100 amp service and do not upgrade to 200 amp during the building upgrade.

Next would be shop air. Get a good compressor and put it somewhere it won't be crazy loud. Get a decent air dryer and filter system set up as well and plumb an air line around the shop.

Building a good foundation before bringing in machines will make life easier for sure.

A VMC is better than a knee mill in pretty much every way; but they are more expensive, much heavier, require more power and they have more complex systems that are prone to failure; especially older machines.

If you do not have experience maintaining, diagnosing and repairing that type of equipment; or the $ to pay a tech to come do it for you - it would probably be better for you to start off with a CNC knee mill.

A $15k VMC is a 5 ton brick that does you no good if it's broken. Repair parts and services like a spindle rebuild, replacement motor or servo drive can be very expensive. The cost is justified if you already have paying production work for the machine. If not, paying $5k for a spindle rebuild is hard to justify. A $5k repair on a knee mill often just means that you scrap it and haul another one home with your F150.
 
Single phase machines are not really a thing. You can run a 3-5 HP spindle motor using a vfd on single phase 220v though.

I would suggest starting with your shop space, not machines. If it has not been done yet; insulate the space, update the wiring, add outlets everywhere, finish the walls and update the lighting. This is far easier to do now without 8 tons of stuff in the way.

After that, I would look into a phase perfect digital phase converter; 20hp if you've only got 100 amp service and do not upgrade to 200 amp during the building upgrade.

Next would be shop air. Get a good compressor and put it somewhere it won't be crazy loud. Get a decent air dryer and filter system set up as well and plumb an air line around the shop.

Building a good foundation before bringing in machines will make life easier for sure.

A VMC is better than a knee mill in pretty much every way; but they are more expensive, much heavier, require more power and they have more complex systems that are prone to failure; especially older machines.

If you do not have experience maintaining, diagnosing and repairing that type of equipment; or the $ to pay a tech to come do it for you - it would probably be better for you to start off with a CNC knee mill.

A $15k VMC is a 5 ton brick that does you no good if it's broken. Repair parts and services like a spindle rebuild, replacement motor or servo drive can be very expensive. The cost is justified if you already have paying production work for the machine. If not, paying $5k for a spindle rebuild is hard to justify. A $5k repair on a knee mill often just means that you scrap it and haul another one home with your F150.
I actually have my shop wired for 220 and air already. I've have a quincy qt-54 air compressor that I built a shed for outside, and my house is on a 200 Amp service, however, the 220 outlets in my garage are only on 60a. I've been an aircraft mechanic/fabricator for most of my life, so my garage has always been for tools and toys, not cars. Also, I have a plethora of tools, just not cutting tools, so that will be a significant investment as well. So getting a cnc mill and lathe might be a cheaper option to start with as this allows me room to tool up.

I would 100% rather get a VMC, but I need a lathe just as much as I need a mill. If I can swing a vmc and a lathe, then that would be the best case scenario. But like you mention as well, VMC's are large and heavy, not well suited for a garage, but doable.
 
I love it here when "experts" make assumptions, and tell people they don't know what they're talking about. Insisting that someone starting out, little to no experience in machining or CNC's, a home shop, no distinct plans for volume widgets, learning and doing one-offs and gunsmithing requires a VMC as a priority off the bat is dubious advice. I've had a VMC at my former business (didn't have room for it when I moved out) I do mostly one-off prototyping for engineering/ R&D projects, testing, test-fixtures, etc. and now have a good-condition manual BP and the Interact. I have not missed the VMC (much) FOR THE TYPE OF WORK I DO. If I have complicated CNC machining to do, or something requiring multiple parts, I have people that know a lot more, are much more efficient, get better results, and have much better equipment than I can (or want to) justify purchasing, maintaining, and becoming expert in all the details of proficiently using it.
I also love it here on one hand the "experts" here often lambast newbies for their naivete regarding the cost and complexity of doing machining correctly and efficiently, and to "leave it to them" (the "experts"), while insisting that a novice go out and buy a VMC....
I couldn't agree more. I'm not really influenced by peoples opinions, I'm interested in facts. Fact, I'm a novice machinist. I've dabble in machining throughout my career, and I know enough to get me in trouble, but not enough to keep me out of trouble. This is where I think a manual/cnc mill would be a great fit for my skills. Can I learn to operate a VMC? Sure, you bet. Would a VMC save me a lot of time, absolutely. But I don't necessarily need it to fill a role in a gunsmith shop. My hope is to have one of everything eventually (or even multiples of everything).

I'm not interested in the super speed aspect as much as I am with the capability. I plan on running a gunsmithing shop, with the hopes of getting into job shop work (machining repair, one off's, and/or prototyping). I would love to get into a nice VMC that does some complex work, but I feel like that's down the road for me. But again, I'm not opposed to a VMC, just has to be a good fit for my budget.
 
I have a Hurco Cnc that I retrofitted 12 years ago.
It has mach3, and Gecko drives.
I can't compete with a machining center with toolchanger, but I quote jobs for my manual mill and run them on this machine.

Sometimes 10, 20, or 50 simple parts.
It works for me.

Every now and then, I'll get a part with a weird profile, qnd program it on the Hurco.
Some of these small runs, I can run my lathe while the Hurco runs production .
It's not ideal, but it works for me.
 
The naive part is thinking a knee mill is easier/simpler to use than a VMC. It isn't. It's a lot harder to make good parts on a light little manual mill that moves around and can barely hold a few thou accuracy over a foot with a skilled operator.

The VMC will make things easy the knee mill struggles with- Like machining hardened materials, you know, like guns are made of?

I knew a lot of nothing when I went into business. I bought a 5500 lb CNC knee mill with a toolchanger as my first CNC mill and boy, what a joke that thing was. I learned real quick why everyone with a real shop told me to start with a quality VMC. I sold that knee mill real quick and bought a real VMC. No regrets whatsoever.

I have a decked out manual Bridgeport and rarely use it. I've almost sold it a few times because it just sits 99.9% of the time. The .01% it gets used it's as a drill press.

Without any real experience I think you may be severely underestimating the value of more iron, a toolchanger and an enclosure with a coolant system.

CNC does not equal production whatsoever. One off parts are no problem. Some machines may be set up with production workholding, but that isn't hard to change. Like pulling a hydraulic chuck off a CNC lathe and swapping on a manual 4 jaw.

Also, there are open VMC's. They just have stub walls around the table. I had one and really liked it for one off stuff, but it was not good for cranking out parts.
 
I love it here when "experts" make assumptions, and tell people they don't know what they're talking about. Insisting that someone starting out, little to no experience in machining or CNC's, a home shop, no distinct plans for volume widgets, learning and doing one-offs and gunsmithing requires a VMC as a priority off the bat is dubious advice. I've had a VMC at my former business (didn't have room for it when I moved out) I do mostly one-off prototyping for engineering/ R&D projects, testing, test-fixtures, etc. and now have a good-condition manual BP and the Interact. I have not missed the VMC (much) FOR THE TYPE OF WORK I DO. If I have complicated CNC machining to do, or something requiring multiple parts, I have people that know a lot more, are much more efficient, get better results, and have much better equipment than I can (or want to) justify purchasing, maintaining, and becoming expert in all the details of proficiently using it.
I also love it here on one hand the "experts" here often lambast newbies for their naivete regarding the cost and complexity of doing machining correctly and efficiently, and to "leave it to them" (the "experts"), while insisting that a novice go out and buy a VMC....
Ok, so your argument is that you don't need a VMC, because you can send the work to someone who has a VMC?? That argument could be made about anything under the sun.

The OP asks our opinion, every one else says skip the CNC knee mill and go straight to VMC. Not because parts can't be made on a knee mill, but because VMC's are nicer to use in every possible way.
 
I love it here when "experts" make assumptions, and tell people they don't know what they're talking about. Insisting that someone starting out, little to no experience in machining or CNC's, a home shop, no distinct plans for volume widgets, learning and doing one-offs and gunsmithing requires a VMC as a priority off the bat is dubious advice. I've had a VMC at my former business (didn't have room for it when I moved out) I do mostly one-off prototyping for engineering/ R&D projects, testing, test-fixtures, etc. and now have a good-condition manual BP and the Interact. I have not missed the VMC (much) FOR THE TYPE OF WORK I DO. If I have complicated CNC machining to do, or something requiring multiple parts, I have people that know a lot more, are much more efficient, get better results, and have much better equipment than I can (or want to) justify purchasing, maintaining, and becoming expert in all the details of proficiently using it.
I also love it here on one hand the "experts" here often lambast newbies for their naivete regarding the cost and complexity of doing machining correctly and efficiently, and to "leave it to them" (the "experts"), while insisting that a novice go out and buy a VMC....
You are entitled to your opinion no matter how wrong it may be.
 
No need for everyone to get worked up. I didn't mean to start the "VMC vs manual" war. I asked for opinions, and I have gotten many (thank you). We all have opinions, and what works best for one individual isn't necessarily the best, nor the worst, but I think it's important to look at everything as a whole to make an educated decision. After all, even if we disagree, we've learned something (right?).

Either way, I've got a lot to consider. I don't know if I should buy one quality machine, or try to get as many different (old/used) machines as possible. On top of which type of machine to buy, I have to decide if I want single or three phase. And if I pick three phase, do I go with a VFD, or a PRC. Then I have what I consider a "minimum tooling list", which I have no idea about, but I'll figure it out as I go I suppose.

Thanks again for everyone's feedback and input. I know this is a very subjective topic, but again, I think it helps us learn.
 
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I have to decide if I want single or three phase. And if I pick three phase, do I go with a VFD, or a PRC.

It's already been said in this thread. There is no real single phase machine option. You might find a couple tiny mills that can run single phase, but they charge a dramatic premium for that.

Phase converters are simple. RPC is a solid choice. If you have too much money and need to piss some away go for a Phase Perfect (that's not a VFD BTW).
 








 
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