# Considering CNC Mill... what should I look for?



## ArmyDoc

I am planning on building my shop this fall, and have been looking at manual mills and lathes.  I had it in the back of my mind that I might want to convert the mill to CNC at some time down the line.  A friend said if that was my plan, I should look at getting a CNC mill in the first place.  I was surprised to find that the CNC weren't all that much more expensive.  Besides the things I would look for in any used mill, like wear on the ways etc, What things do I need to be aware of and watch out for when evaluating a CNC mill?


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## BGHansen

I've picked up two used CNC mills.  Not an authority by any stretch, but here's what I looked at and questioned.  First thing I asked is "why are you selling the mill?"

First one was a 1981 Bridgeport Series 1 2HP mill with an Anilam Crusader 2 controller (circa 1985).  Answer to my question was he'd used the mill in a side business shop (was a tool and die maker).  He was retiring and selling off his equipment.

The table runs on ball screws, so should have little backlash, but ball screws can wear out.  I put a 10th indicator on the spindle and checked backlash relative to the table X/Y hand wheel micrometer dials at various points in the table travel. 

Also checked for table flatness by running the table back/forth with the indicator on the table.  Checked the spindle/quill for looseness at the bottom of the 5" travel.  Ran the mil through its speed range for wobble/noise.  Verified that boring and the kick-out worked.

I knew nothing about the CNC, so let the owner plug in a few routines to run it through its paces.


Second one was a Tormach 1100 Series 3.  Answer to my question was he used the Tormach in a side business (www.yourlittleCNCshop.com) but instead of running his parts on the Tormach, had worked out a deal with his boss (he is a machinist) to run his stuff on a Haas CNC at work.  He had jobs that took 20 minutes on the Tormach, but only 3 on the Haas.

Did the same sort of checks though the Tormach is a square column mill, so no quill to check.  We checked for "lost motion" (Tormach's term) with an indicator against a 1-2-3 block.  Also cut a round pocket in a chunk of aluminum and measured the diameter across the X and Y (were different by just under 0.001").


You might want to look at age of the controller.  My BP Anilam has a problem with the RS-232 port.  I cannot load programs to/from the controller.  There is a shop in North Carolina that works on them at a shop rate of $250 / hour.  I'd likely pull the Anilam and go with a retrofitted Centroid Acorn controller before trying to get the Anilam fixed.  All other functions on the Anilam work fine.

My BP has a 2-axis controller.  The Z-axis is manual.  After learning the programming in 2-axis, I had a bit of buyer's remorse and wished I'd had a 3-axis machine.  I was planning on adding the 3rd axis on the quill or knee (Jim Dawson has a thread here on his quill CNC addition, CooterBrown has one on a BP knee addition).  I ended up buying the Tormach instead, kept the BP also.


Bruce


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## Boswell

Many conversions use Mach3 (so do I currently). Mach3 has been around for a while and was originally setup to a parallel port to connect to the Breakout and motion control boards. Microsoft support for the parallel port ended with Microsoft XP. It is an easy upgrade to use an Ethernet Smooth Stepper to replace the parallel port connection but you should be aware that if you look at a used system that relies on a parallel connection and and old MS XP based computer, you can expect to upgrade all of that sooner or later and probably sooner.  I guess the underlying message here is that you need to evaluate the CNC control software chain as there are many out there and some are better than others. Three key parts to evaluate. CNC software (Mach3), Breakout board and motion controller. These can be all separate or combined is various combinations based on the system. Some are open source (LinuxCNC) other are proprietary. Both have pros and cons. Some target a hobby user and others will be full on commercial systems.  As you start to find some specific system, share the details here and I am sure you will get a lot of expert feedback.


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## Mini Cooper S

I was also looking at converting a manual machine into a CNC also, as I was watching for something to come on the market, I found a Series 1 Bridgeport CNC circa 1978.  The hardware was in very good shape but as you can imagine, the controller was less than reliable.  I wound up stripping the guts out, and one of the two electrical cabinets on the machine.  I then fitted a spare PC that I had, along with a PMDX- 454 Smartbob, PMDX-407 spindle control, Gecko G214 Microstep Drives and Mach4 software. It took a while along with a lot of internet research to learn how to make it all work, but it turned out to be a descent machine when I was done.

I say "when I was done", that really didn't happen as I am always adding some new feature to my project. All totaled I have $5900 in the machine.   

Richard



​​


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## samstu

I'm no expert but will give you my opinion.

Maybe first decision is the mill a project or  is the mill for projects?  If the mill is a project, old mills with anilam, boss and other controllers make great conversion candidates as they can be found in low hour condition for little green. They are cnc ready with ball screws and sometimes servos can be reused.  So doing homework before purchase is key.  Converting a manual mill to a cnc is usually not worthwhile due to needing to change to ballscrews, etc.  Mach 3 has a good following while Centroid has diy conversions to real industrial controls.  Masso is another interesting controller but isn't fully baked in my opinion.

If the mill is for doing projects, get one ready to go.  Meaning modern controllers and conversational controls have real value, especially if time is of value.  You can make older anilam etc work but parts, support, etc are spotty and can be pricey.

I almost purchased a bridgeport with 12 year old centroid control.  It worked great and was accurate but when I researched this machine, I found that it had been for sale for nearly a year (it's still for sale) confirming a limit resale potential.  I then purchased a cnc mill from HGR, but when I got it home, I learned how badly worn it was.  So, I returned it for full refund.

In the end,  I purchased a Tormach 1100 series 3 with a full enclosure and power drawbar.  These mills sell quickly, have good resale, have "factory" support, and parts are cheap.  Spindle bearings from tormach are $126 a pair for lower and same price for uppers.  Pathpilot software updates are free. Sure there are limitations and yes, I'd rather have a Haas TM or even a nice bridgeport conversion but it's a hobby and the tormach is forgiving, repairable, and not nearly as messy as an open bridgeport.  It's more saleable than a DIY conversion as these vary in success and usability.


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## JimDawson

I would try to find a CNC machine that is in good mechanical shape.  I wouldn't worry about the controls at all, that's the cheap and easy part to fix. A CNC with dead controls should sell at near scrap price.  My preference is a manual/CNC machine.  There are a few of these around.


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## kb58

Another thing to keep in mind if this is your first mill - will you want to be able to use it as a manual machine? I did, and giving up the handles for CNC didn't make sense_ in my case_, since I do odd one-off things. Some CNC mills retain the cranks for manual operation and some don't, so choose wisely.


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## ArmyDoc

samstu said:


> Maybe first decision is the mill a project or  is the mill for projects?  If the mill is a project, old mills with anilam, boss and other controllers make great conversion candidates as they can be found in low hour condition for little green. They are cnc ready with ball screws and sometimes servos can be reused.  So doing homework before purchase is key.  Converting a manual mill to a cnc is usually not worthwhile due to needing to change to ballscrews, etc.  Mach 3 has a good following while Centroid has diy conversions to real industrial controls.  Masso is another interesting controller but isn't fully baked in my opinion.
> 
> If the mill is for doing projects, get one ready to go.  Meaning modern controllers and conversational controls have real value, especially if time is of value.  You can make older anilam etc work but parts, support, etc are spotty and can be pricey.
> 
> I almost purchased a bridgeport with 12 year old centroid control.  It worked great and was accurate but when I researched this machine, I found that it had been for sale for nearly a year (it's still for sale) confirming a limit resale potential.  I then purchased a cnc mill from HGR, but when I got it home, I learned how badly worn it was.  So, I returned it for full refund.
> 
> In the end,  I purchased a Tormach 1100 series 3 with a full enclosure and power drawbar.  These mills sell quickly, have good resale, have "factory" support, and parts are cheap.  Spindle bearings from tormach are $126 a pair for lower and same price for uppers.  Pathpilot software updates are free. Sure there are limitations and yes, I'd rather have a Haas TM or even a nice bridgeport conversion but it's a hobby and the tormach is forgiving, repairable, and not nearly as messy as an open bridgeport.  It's more saleable than a DIY conversion as these vary in success and usability.



Thank you.  There were a lot of good points in there.  The part about having ball screws to start vs the cost of replacing is why I had heard it would be better to start with a CNC machine.

I guess that I lean more towards the mill being for projects than the other way round.  I suspect that tearing apart a mill is a larger project than I am ready for, and the idea of replacing electronics is terrifying, rather than exciting.  I have no problem replacing components - I can pop out an IO card, hard drive etc and plug a new one in it's place, but that's about the extent of it.  I've never tried to build a computer from various components.

I read that Haas, Fadal, Fanuc and Wells-Index are all worth looking at, because they are still in business and supporting their machines.  I will add Tormach to that list.  Had heard anillam and Boss were to be avoided due to age.  Real problem is it seems that only Bridgeports are available around here.



JimDawson said:


> I would try to find a CNC machine that is in good mechanical shape.  I wouldn't worry about the controls at all, that's the cheap and easy part to fix. A CNC with dead controls should sell at near scrap price.  My preference is a manual/CNC machine.  There are a few of these around.


How easy and cheap?  If it's a matter of pull out the old system and plug in an new one, I can probably handle that.  But I don't know about wiring at a pin level.  I guess if you're replacing everything, it's pretty much all together and all you are doing is connecting it to the servos.  That wouldn't be too hard.  I guess what I'm saying is plug and play with components is about my speed.  If it's wiring soldering etc, not so much.



kb58 said:


> Another thing to keep in mind if this is your first mill - will you want to be able to use it as a manual machine? I did, and giving up the handles for CNC didn't make sense_ in my case_, since I do odd one-off things. Some CNC mills retain the cranks for manual operation and some don't, so choose wisely.


I have been going back and forth with this.  Part of me says yes, I want to use it as a manual machine.  But that may be just because I have been thinking about manual machines and making things in those terms.  That's also why I lean towards a Bridgeport VMC type machine, rather than a fully enclosed unit.  Part of me says "Plugging in a piece of metal, and pressing start isn't really making it yourself."  But the part of me is focused more on the part , and doesn't want to be doing all of the repetitive steps needed to make it says, "just let the machine do that."   Also, some of the things I want to make would require 4th axis control with simultaneous movement, which I couldn't do manually anyhow. 

I've read that a pendant can provide full manual control that is even better than hand dials.  What do you think about that?


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## kb58

ArmyDoc said:


> ...Part of me says "Plugging in a piece of metal, and pressing start isn't really making it yourself."  But the part of me is focused more on the part , and doesn't want to be doing all of the repetitive steps needed to make it says, "just let the machine do that."   Also, some of the things I want to make would require 4th axis control with simultaneous movement, which I couldn't do manually anyhow.
> 
> I've read that a pendant can provide full manual control that is even better than hand dials.  What do you think about that?


I meant more about the best use of your time. If you just want to drill some holes, or face a surface, sitting down at the PC and setting that up takes way longer than just doing it yourself, manually on the mill. That said, yes, if you have a pendant/dongle/control box, then I guess handles have gone the way of the dodo.


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## ArmyDoc

kb58 said:


> I meant more about the best use of your time. If you just want to drill some holes, or face a surface, sitting down at the PC and setting that up takes way longer than just doing it yourself, manually on the mill. That said, yes, if you have a pendant/dongle/control box, then I guess handles have gone the way of the dodo.


Ah.  I see what you mean.  Yes, for simple operations, CNC programming would take a lot of time.  
I would definitely want some form of manual control.


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## JimDawson

ArmyDoc said:


> How easy and cheap? If it's a matter of pull out the old system and plug in an new one, I can probably handle that. But I don't know about wiring at a pin level. I guess if you're replacing everything, it's pretty much all together and all you are doing is connecting it to the servos. That wouldn't be too hard. I guess what I'm saying is plug and play with components is about my speed. If it's wiring soldering etc, not so much.



Modern retrofit CNC controls are pretty easy install, well documented.  Of course there is some wiring, but not overwhelming, and no soldering needed.  Look at it as a skill building experience.  I have a very low tolerance for 30 year old controls technology, so IMHO upgrading is the only way to go.  Costs could run from a couple hundred dollars on the extreme low end to as much as you want to spend.  Like anything else, you get what you pay for.  My CNC mill originally had an Anilam control and I ran it until if finally failed, right in the middle of a production job.  I did the retrofit and was back up and running in 12 hours, didn't even take the job off of the table.  I was planning on the retrofit when that job was done so had all of the parts on the shelf.

Under no condition would I convert a manual machine to a CNC without having a well equipped machine shop available.  Too many bits & pieces need to be made to make everything fit.

I find that using a pendant control is very uncomfortable for me, you can't feel what the machine is doing.  I want my hands on the handwheels, but I have over 50 years of running manual machines. 

I do have to admit that getting a CNC machine actually made me look like a machinist, my part quality went way up and allowed me to easily do things that would take hours or be next to impossible to do with a manual only machine.


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## Chipper5783

ArmyDoc said:


> I have been going back and forth with this.  Part of me says yes, I want to use it as a manual machine.  But that may be just because I have been thinking about manual machines and making things in those terms.  That's also why I lean towards a Bridgeport VMC type machine, rather than a fully enclosed unit.  Part of me says "Plugging in a piece of metal, and pressing start isn't really making it yourself."  But the part of me is focused more on the part , and doesn't want to be doing all of the repetitive steps needed to make it says, "just let the machine do that."   Also, some of the things I want to make would require 4th axis control with simultaneous movement, which I couldn't do manually anyhow.
> 
> I've read that a pendant can provide full manual control that is even better than hand dials.  What do you think about that?



I've done a lot of manual machining.  I have 2 good manual mills.

Recently, I got a 20 year old Bridgeport VMC - it is fully enclosed (I did not know you could get a VMC any other way).  Fully enclosed is awesome - I certainly would not want it without the full enclosure.  After ~ a year of messing around with it, I'm pretty comfortable with G-coding direct at the machine.  I still have not found the feature of "plugging in a piece of metal and pressing start".  That would be a very handy feature!

The CNC mill is great, because you can make parts that would be very difficult to make on a manual machine.  My learning is that the CNC is very much like a manual machine, except you send a line of code instead of cranking a handle.  The machine is dumb, it only does what you tell it to do.  It is 100% up to you to tell it what to do.  If you tell it to do something wrong, it will try to do that too.  Machining with a CNC machine is still machining.

You could get someone else to program the part program (often a company will have one or two setup guys, then a bunch of operators) - then you just plug in the piece of metal and press the start button.  I agree that isn't really making it yourself.

Get a CNC mill, learn to run it.  The learning curve is steep - even if you are really comfortable with machining.  It opens up some fantastic capabilities.


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## ArmyDoc

JimDawson said:


> Modern retrofit CNC controls are pretty easy install, well documented.  Of course there is some wiring, but not overwhelming, and no soldering needed.  Look at it as a skill building experience.  I have a very low tolerance for 30 year old controls technology, so IMHO upgrading is the only way to go.  Costs could run from a couple hundred dollars on the extreme low end to as much as you want to spend.  Like anything else, you get what you pay for.  My CNC mill originally had an Anilam control and I ran it until if finally failed, right in the middle of a production job.  I did the retrofit and was back up and running in 12 hours, didn't even take the job off of the table.  I was planning on the retrofit when that job was done so had all of the parts on the shelf.


That's reassuring - the documentation portion in particular.  It's not like I haven't repaired wiring.  If is as simple as "this connects to that"  I can do it.  I just need to be told what goes where.  It's always a matter of not knowing what I don't know that makes me nervous.


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## Chipper5783

Doing a manual to CNC conversion?  Back to the question above whether you want a project (which is fine) or you want to do projects?

The purpose built machines have so many good features, which are possible to implement on a home built conversion unit - but I suggest it will be much cheaper and better to purchase that capability up front.  What features? - full enclosure, tool changer, flood coolant, 4th axis, protected slides and systems, wide speed range, chip conveyor,  . . .  .  It is all possible on a home built conversion, and my hat is off in admiration for anyone who does that.  I suggest it is much cheaper to purchase what you want / need.

If you buy a machine, don't think that means you can't buy another one.  Go ahead and buy yourself a manual mill, play with it.  In a couple years, get a CNC mill, then you'll have a better idea of what you want/need.


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## ArmyDoc

Chipper5783 said:


> You could get someone else to program the part program (often a company will have one or two setup guys, then a bunch of operators) - then you just plug in the piece of metal and press the start button.  I agree that isn't really making it yourself.
> 
> Get a CNC mill, learn to run it.  The learning curve is steep - even if you are really comfortable with machining.  It opens up some fantastic capabilities.


The only time I worked in a machine shop was one summer in college.  They had guys who did that.  I tried talking to the guy who running a cnc machine, but he was more of a machine operator than a machinist.  
I have a very small amount of experience running a bridgeport CNC  mill.  It was not easy!

One thing I do have going for me is I know a guy in California that programs G code for a living.  Hadnt thought about that till now...  feelin' more confident.  Thanks!


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## bakrch

One "hidden" feature in some CNC mills is Custom Macro B language. With FANUC it is usually a free feature. You can essentially write your own canned cycle to do the more mundane tasks. For instance ... bolt circle, grid drilling, pocketing, slotting. You essentially use the control as an elaborate calculator with variables, formulas, conditional loops, branching, etc ...

If the machine control does not have the feature activated or is behind a ridiculous paywall (looking at you HAAS. $2800), there is a nice piece of software called NCPlot that you can write macros with and then convert it to regular g-code. Last I checked, NCPlot was about $300 and supports up to 4 axes. The back and forth can be a little annoying, but it's far faster than drawing something new on CAD. Just change a few numbers, drop a file into a folder, click a button and load the g-code. Mach 4 industrial also has the macro feature for less than half of what HAAS charges.

I have our mills at work loaded with a bunch of macro programs that the machinists use regularly. None of them know how to code, but they can walk up to a gcode mill and make parts with very little training. Handy feature for repetitive tasks. This is essentially what many conversational controls are, but the macro is working behind the scenes hidden behind a proprietary GUI.


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## bakrch

bakrch said:


> One "hidden" feature in some CNC mills is Custom Macro B language. With FANUC it is usually a free feature. You can essentially write your own canned cycle to do the more mundane tasks. For instance ... bolt circle, grid drilling, pocketing, slotting. You essentially use the control as an elaborate calculator with variables, formulas, conditional loops, branching, etc ...
> 
> If the machine control does not have the feature activated or is behind a ridiculous paywall (looking at you HAAS. $2800), there is a nice piece of software called NCPlot that you can write macros with and then convert it to regular g-code. Last I checked, NCPlot was about $300 and supports up to 4 axes. The back and forth can be a little annoying, but it's far faster than drawing something new on CAD. Just change a few numbers, drop a file into a folder, click a button and load the g-code. Mach 4 industrial also has the macro feature for less than half of what HAAS charges.
> 
> I have our mills at work loaded with a bunch of macro programs that the machinists use regularly. None of them know how to code, but they can walk up to a gcode mill and make parts with very little training. Handy feature for repetitive tasks. This is essentially what many conversational controls are, but the macro is working behind the scenes hidden behind a proprietary GUI.



Here is an example. This macro is actually included with NCPlot, but I modified it slightly to be in our HAAS mill at all times. All the machinist needs to do is change the numbers (to the right of the equals sign) inside of the yellow box, and all of the calculations happen in real-time as the program runs.


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## Boswell

My CNC mill can be run manually but I find even for simple cuts, I use the CNC capabilities.

The other day, I need to clean up one side of a piece of bar stock. and it was easier to type G1 X10  than to turn the X handle 100 revolutions.


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## Aaron_W

You might give some thought to finding a small CNC mill, like a Tormach, or CNC mini mill. Sherline offers CNC ready and complete CNC packages, and there are ready made kits to convert some of the popular mini and small mills to CNC. Then use that to see if CNC is really something you want to dive into. Maybe even think about a 3D printer or CNC router which use a lot of the same programs. Cheaper to buy, easier to move and easier to sell if CNC isn't your thing.


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## ArmyDoc

Aaron_W said:


> You might give some thought to finding a small CNC mill, like a Tormach, or CNC mini mill. Sherline offers CNC ready and complete CNC packages, and there are ready made kits to convert some of the popular mini and small mills to CNC. Then use that to see if CNC is really something you want to dive into. Maybe even think about a 3D printer or CNC router which use a lot of the same programs. Cheaper to buy, easier to move and easier to sell if CNC isn't your thing.


I appreciate the advice, and caution I hear in your post.  I do have a 3D printer that I bought last year.  I've only done one project from start to finish yet, but it was a lot of fun.  It's a 3D puzzle, octogon in cross section, that twists on  it's central axis.  There are 4 oval tracks of marbles that when you twist 45 degrees become a spiral.  Mix up the marbles, then try to figure out how to get them back to start.  I got the idea from a hexagon one that I saw on line and printed.   Here's a link to the one on line that I printed.  




Here is mine in each of the 4 orientations before returning to the original, but 180 degrees from start:







As you can tell, while I was able to make it, I haven't solved it yet!


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## matthewsx

I might not be the ideal person to ask since I only have a CNC and I'm still building it & figuring out how to use it. I do miss my Gorton 1-22 MasterMill though and often think of how useful it would be for building my CNC.

Honestly what I would suggest is getting a very capable manual machine first. The job shops I've been in have both the big VMC for running production jobs and a Bridgeport for one off's and building fixtures.

Then, once you get more comfortable with your 3D printer and have some experience with the manual mill you can decide if you want a full blown VMC, a smaller hobby type CNC like a Tormach, or want to do a conversion of another manual which you will be better able to accomplish with your existing manual machine for making parts.

Since you're just getting ready to jump in there's really no way to know what you don't know. This place is great but we all have our own experiences and resources, probably different from yours. If you can design and print cool stuff on your 3D printer then you can transfer those skills to a CNC, but there are still going to be times when you just want to put a piece of metal in the vise and drill a few holes.

The part about enclosures is definitely something to consider, from my limited experience CNC throws a lot more chips and flood coolant is probably mandatory for taking big cuts. I definitely want to build one for my little mill/drill project but that will limit the size of part I can work on. In a home shop you will have both projects you design and build from scratch and repair jobs that can sometimes be odd shaped or bigger than the table on your machine. Factor that into your decision making as well.

If space and money weren't a problem I would probably have one of the combination horizontal/verticals like the Wells Index you were looking at in the other thread and a Tormach with a full enclosure. We actually have a Tormach dealer in town here 

JMHO,

John


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## BGHansen

Here are a few Craig's List machines in your general area.  I used the search engine "www.searchtempest.com".  Plug in your zip, max distance, and a price range if you want.

Bruce

Looks to be a 4-axis Sherline mill and lathe for $3500








						Plug and Play CNC workshop - tools - by owner - sale
					

Thousands of things can be made with this setup, CNC lathe and 4 axis mill, has everything to get...



					gadsden.craigslist.org
				




Meaty, beefy Seki 3-axis with a 10 x 54 table.  Has an old Anilam controller (1100?).  Asking $6500








						Seki XL 3 Axis CNC Mill - tools - by owner - sale
					

Selling a great Seki XL Knee Mill. It is a full 3 axis CNC with Analim controls. Can be used...



					atlanta.craigslist.org
				




Round column Rong Fu type mill, 3 axis.  Seems a bit high at $7500, especially with no tooling pictured.








						CNC Milling Machine - 3 Axis + - tools - by owner - sale
					

CNC Mill 3 Axis Plus Port for 4th 230 VAC Single Phase Dell Computer Monitor Keyboard & Mouse...



					charlotte.craigslist.org
				




Small Boxford table top 3-axis, asking $5000








						CNC Milling Machine - tools - by owner - sale
					

Boxford model 190VMCxi, 3 axis CNC Vertical Machining Center featuring Boxfords Complete Software...



					charlotte.craigslist.org


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## ArmyDoc

Yes, familiar with search tempest.  Of the ones you posted, the seki XL is the one that most interests me.  Only concern is very old controls. 
I'd be interested to know what others with more experience think about those machines, as well as these three:








						Tree Millennium 3100 3-Axis CNC Vertical Milling Machine - The Equipment Hub
					

Visit here to learn more about this Tree Millennium 3100 3-Axis CNC Vertical Milling Machine for sale. Contact us today for additional details.




					www.theequipmenthub.com
				












						Bridgeport EZ Trak 9" x 48" 2-Axis CNC Vertical Milling Machine - The Equipment Hub
					

Visit here to learn more about this Bridgeport EZ Trak 9" x 48" 2-Axis CNC Vertical Milling Machine for sale. Contact us today for additional details.




					www.theequipmenthub.com
				



And








						Bridgeport Series II Interact 2 3-Axis CNC Milling Machine - The Equipment Hub
					

Visit here to learn more about this Bridgeport Series II Interact 2 3-Axis CNC Milling Machine for sale. Contact us today for additional details.




					www.theequipmenthub.com


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## Aaron_W

ArmyDoc said:


> I appreciate the advice, and caution I hear in your post.  I do have a 3D printer that I bought last year.  I've only done one project from start to finish yet, but it was a lot of fun.  It's a 3D puzzle, octogon in cross section, that twists on  it's central axis.  There are 4 oval tracks of marbles that when you twist 45 degrees become a spiral.  Mix up the marbles, then try to figure out how to get them back to start.  I got the idea from a hexagon one that I saw on line and printed.   Here's a link to the one on line that I printed.
> 
> 
> 
> 
> Here is mine in each of the 4 orientations before returning to the original, but 180 degrees from start:
> View attachment 335891
> View attachment 335892
> View attachment 335893
> View attachment 335894
> View attachment 335895
> 
> 
> As you can tell, while I was able to make it, I haven't solved it yet!



Ok then you at least have an idea what you are getting into with a CNC machine. It seems like a lot of people think they are like a Star Trek replicator, and don't realize there is work involved it getting a nice part out of it.


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## BGHansen

No direct experience with those machines though our Tool Room at work has a BP Series II GARGANTUAN mill like the one pictured.  Check the ad, no skidding fee as it weighs 5000 lbs.  The one at work has what looks like a similar controller.  The on-board memory is limited, so they dip-feed from another computer.

Our Tool Room also has an EZ Trak BP though it has a 42" table.  Problem I see with this one is it's 2-axis.  My BP has 2-axis also, you'll want the 3rd axis once you get a taste of 2-axis controls.

Tree made good mills I believe in Racine, WI.  I have a buddy who taught at Gateway Technical College in the Machine Tool school in Racine, they used Tree mills there at the time.  The control is an older Anilam 1100 series.  Like Jim Dawson mentioned, the controls can be replaced with a Galil or Centroid card.  You might check with Jim as he's the expert, but the servos on the machine would probably not need to be updated.

Kicker on the BP Series 2 and Tree is the Z-axis controls appear to be on the quill which is typical.  It gives you ~5" of travel in the Z-axis under program control.

Bruce


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## ArmyDoc

BGHansen said:


> No direct experience with those machines though our Tool Room at work has a BP Series II GARGANTUAN mill like the one pictured.  Check the ad, no skidding fee as it weighs 5000 lbs.  The one at work has what looks like a similar controller.  The on-board memory is limited, so they dip-feed from another computer.
> 
> Our Tool Room also has an EZ Trak BP though it has a 42" table.  Problem I see with this one is it's 2-axis.  My BP has 2-axis also, you'll want the 3rd axis once you get a taste of 2-axis controls.
> 
> Tree made good mills I believe in Racine, WI.  I have a buddy who taught at Gateway Technical College in the Machine Tool school in Racine, they used Tree mills there at the time.  The control is an older Anilam 1100 series.  Like Jim Dawson mentioned, the controls can be replaced with a Galil or Centroid card.  You might check with Jim as he's the expert, but the servos on the machine would probably not need to be updated.
> 
> Kicker on the BP Series 2 and Tree is the Z-axis controls appear to be on the quill which is typical.  It gives you ~5" of travel in the Z-axis under program control.
> 
> Bruce


Do you think 5" is problematic?  If I ever did a 4th axis (which seems likely to me) it would give a 10 inch swing...


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## JimDawson

ArmyDoc said:


> Do you think 5" is problematic?  If I ever did a 4th axis (which seems likely to me) it would give a 10 inch swing...



You have about 5'' on the quill, but the knee will give you another 16'' or so.  The knee will bring the table up to almost touch the retracted spindle.  A 10'' swing on the 4th axis is more than enough.

Of the mills above I like the Seki, but that's just because it is most like mine.


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## BGHansen

The 5" travel isn't problematic as those mills don't have a tool changer.  The Tormach has about 16" of Z-axis travel.  Mine has a tool changer too.  Advantage of the added travel is if your part requires tooling with too wide range of tool heights, you don't have to touch the knee to a pre-determined spot for the tools.

For example, my Tormach tension/compression tapping head has a tool height with a tap in it of around 8".  An end mill holder with a short end mill is around 3".  A larger drill chuck with a jobber length drill is about 6".  A I can run the job from the tool changer and walk away, the 16" of travel can handle the big range of tool lengths.

Same job on a 5" travel machine would require some planning for knee table heights, so no "lights-off" walk-away from the job.  Not a big deal as all of the tool changes are manually done, so you need to tend to the machine.  Another thing is spindle control.  Don't know if the EZ-Trak BP has spindle speed control via the CNC.  The one we have at work does not.  On my Tormach the speeds are under program control so a tap drill could be at 2000 RPM, then tap at 200 RPM.  Again, not a big deal as you are doing the tool changes manually anyhow.

Bruce


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## 7milesup

Interesting thread ArmyDoc.  I have been thinking about converting my 833T to a CNC machine.   There is actually a conversion kit for it and even with the cost of the kit, the electronics and the mill itself, you end up way less than a comparable Tormach or similar.  To me, for the money, you just can't beat it, but of course that is dependent on what you want to do and how big of a machine you need/want.  I don't have anything against Tormach, but when I look at value, this conversion is high on that list...---> 833TV to CNC conversion. He lists all of the parts he used and how he went about it. The biggest issue for me is my 833T is a geared head and I would want to convert it to a variable speed belt drive, which will take some fanangling. The 833TV has the belt drive head so that is no longer an issue. Plus, you get a new machine with a 5 year warranty.


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## ArmyDoc

They have a kit  for his conversion too. https://www.heavymetalcnc.com/pm833t/  Pretty nice.

I think the hardest thing for me is know is how much mill I'm going to need.  If I go CNC, I will definitely want to have 4th axis capability at some point.  Even in a manual mill, many of the projects I envisions require some kind of rotary table to be able to complete them.  This requires a larger table, and I think the desktops are just too small.   I don't know the exact size of these devices, but I'm guessing 8-12 inches by the time you include a chuck, and if you need a tailstock support, that's even more space gone.  I suspect a 35 inch table is as small as I should consider, and probably need to be looking at the 49+ sized machines.


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## 7milesup

probably need to be looking at the 49+ sized machines. 

That eliminates all Tormach and a lot of the Haas machines.  The Haas TM2 has a 40" work envelope but it starts at $30,000.  Not sure where you will find that size.  Used Bridgeport maybe?...


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## ArmyDoc

7milesup said:


> probably need to be looking at the 49+ sized machines.
> 
> That eliminates all Tormach and a lot of the Haas machines.  The Haas TM2 has a 40" work envelope but it starts at $30,000.  Not sure where you will find that size.  Used Bridgeport maybe?...


All of the Haas Vertical mills were designed to support a 4th and even 5th axis, so the units are much more compact.    Tormach has the micro arc 4th axis.  But all of these options $$$$.  If I want a 4th axis, I'm probably going to have to make it my self, using a servo, harmonic drive and chuck.  That's what takes up space.  
Isn't that always the case?  You can have everything you want, have it ready made, have it cheap.  Pick 2

I have to pick my battles based on budget.  This years primary budget is going to be to getting the shop done.  Once the structure is built, Electricity and AC is next.  I'm pretty sure I can hit those goals in the next 4-6 months.  Until they are hit, there's no point in really shopping for machines etc because I don't have anywhere to put it.

After the shop is up, if I have anything left, then I'd like to get either a lathe, or a mill. I sincerely doubt I will be able to get both. But that's fine. I have more than enough to learn on whichever one I get. Tentative budget will be $10k including initial tooling for one machine. That's all assuming I don't blow the budget out of the water building the shop... in which case I guess it'll be next year some time before I can buy anything. Bonuses usually don't come till June.


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## BGHansen

My Tormach 1100 has X/Y/Z travels of 18"/9.5"/16.25", table is 34" x 9.5".  My Bridgeport has a 9" x 42" table with X travel of 24", think the Y is at least 12".  Yes, wish the Tormach had a little more though I haven't done anything to exceed it yet.  Guys have replaced the Y axis ball screw and some other work to get the Y axis up to 11".

My Tormach has an 8" 4th axis.  I've used it for a couple of jobs, most intricate was cutting some helical gears.  It came with the mill; if I was doing it from start I'd go with a 6" super-spacer 4th axis.  There are a couple of problems with Tormach's 4th axis.  One, the regular 4th has the motor on LH side of the rotary table as viewed from the front.  That puts the 4th on the LH side of the table.  They recommend NOT using the automatic tool changer as clearance is a problem.  The super-spacer version has the motor on the opposite side so it mounts on the RH side of the table; ATC is still usable.  Another plus for the super-spacer is the head rotates like a dividing head.  To cut the helical gears, I mounted the 4th on a tilt table which took it even higher.

If you go with a BP type mill you'll get really nice travels.  The Centroid Acorn board is a nice upgrade for older controllers and gives you a 4th axis port.  It also will control a VFD so you have spindle control.

Bruce


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