[butthead]

I need to buy a benchtop milling machine. I'm trying to find the best quality machine, and I'm sort of going around in circles. Looked at all the specs, and read some reviews - but it's not as easy as saying, "I'll take the Bridgeport." It would appear that they're all made overseas, and I haven't had the best experience with Chinese precision craftsmanship.

I've been looking at the IH (Charter Oak) machine, and I've been looking at the CNCMasters Baron and CNC Max. Any input from others - on what the best machine is, in terms of precision and quality, and which to avoid?

Thanks.

[rwpilot]

I was going to ask the same question. I have never used a milling machine before. I'm looking at the Charter Oaks 12Z, Precision Matthews PM-932M, Bolton ZX45 and Grizzly G0755. I will mostly use it for aluminum for now to make parts for an airplane I am building. I'm sure it will get used for other materials as well. I had no plans to convert to CNC until I joined this site. Now both my wife and I are fascinated by them. Watched lots of videos.

Should I stay with the base unit like the Bolton ZX45 so I'm not paying for power feeds that will get replaced for the conversion? It will be at least a year before I start a conversion.

What really is the difference between the models I listed other that the power feeds or larger table? Any one better than the other?

Space is not an issue.

Any recommendations on learning the programming for CNC?

Thanks in advance for any help.

[dracozny]

The advantage to the charter oaks as opposed to the Bolton Zx45 (that I own) or any of the others, is that Charter Oaks has actually put some time into making sure the machine is up to snuff. On top of that they have increased the work envelope as well. if you hunt around on the forum you will see what kind of work has been needed on each of these machines to bring them up to snuff.

[butthead]

Thanks for that. That's one vote for Charter Oak. Any body else want to throw in their thoughts?

[mhackney]

What are your requirements and your constraints. Like everything, it is a tradeoff. If you only need a small machine for learning, we could point you towards a Shoreline or Taig. If you need a bog machine with a large work envelope, that's in the other direction. It sounds like you are looking for a turnkey machine. The sub $15K options are rather limited and have strengths and weaknesses so knowing what your application/requirements are will help. The Novakon and Tormach mills are both good choices. Tormach has a bigger following but Novakon has some great features.

cheers,
Michael

[butthead]

Well, it's going to be in a shop room for a number of years, to do a variety of different one-off projects on. So flexibility to do as many different things (or different sized things) as possible is important. But I guess more important than that is that, big or small, I'd want the thing to be as precise as possible, not some sloppy junk that's going to produce parts all over the map. I know that's a lot to ask of something sub-$15k.

[Wiggles84]

It also might help to know what you consider precise. Are you talking .005"? .001".0005"?.0001"?

The more precise you go, the bigger the $$$$$$$

In the end it's still just a benchtop mill

Andrew

[MetDetect]

My Charter Oak 12z just arrived. You can't appreciate just how big this mill is until you see it in person. That's a G4003G 12x36 lathe in the background, see the stainless toolbox next to it...the 12z is taller than that toolbox sitting on the floor. Its really pushing the definition of "bench top".



I spent several months researching before purchasing the Charter Oak. For what its worth here's my 2 cents.

I have been down this road before with bench top mills. I owned one of the early IH CNC mills, it was JUNK from day one and never performed as advertised. I know the problem areas and short comings of the bench top CNC mill path. Initially I found the exact same problems being reported across multiple brand bench top mills as I had experienced before. The mills also had the exact same short comings. So I shifted to a Haas Super Mini Mill 2, that's about the max size CNC mill I could squeeze into my space. I can afford the $68k all decked out with a side mount tool changer and all the goodies but after I wiped the drool off myself it just made no sense, not for one off hobby purposes. $68k would buy me a lot of machine time in a real shop with a way bigger, faster mill than that Haas.

About that time I became aware of the Charter Oak 12z. As someone in this thread mentioned they have addressed the problem areas and short comings. The number one game over issue is the ways. If the ways are crap its a big waste of time and money trying to convert the thing to CNC. Typically I found people still reporting problems today of the ways being tight at the top and bottom and loose in the middle across multiple brands. So you have to run the gibs loose which causes all kinds of issues. If a mill vendor starts talking to you about lapping the ways run away. I questioned Charter Oak on this extensively and yes at one point they had this same issue everyone else has but assured me they have this problem resolved, no lapping is required. That's good because I told them I would ship the mill right back for a refund this is a deal ender issue for me. The ways need to be true and consistent with the gib reasonably snug and no binding.

Next up is spindle speed. My old RF45 topped out around 1920 rpms, I found this painfully slow for aluminum and plastics. There's nothing quite like a gear head spinning flat out going WHAAAAAAAAAAA at 90 decibels for hours on end and finish wise aluminum likes more speed. Well Charter Oak has two options. First you can upgrade to a 3hp 3 phase motor with a VDF which gives you over 3,000 rpm spindle speed plus variable speed. Second, there is a guy who makes a two speed belt drive conversion for the Charter Oak that boost spindle speed to over 5,000 rpm. Charter Oak upgrades the spindle bearings, they will handle 7,000 rpm. A belt drive conversion is also quieter. Here's a video of the guy who makes the belt drive conversion testing it at 9,000 rpm.

https://www.youtube.com/watch?v=HeoKGTWeBEU

Next up is the big heavy head which wants to pitch forward on the ways vs the typical small mounting surface of your average RF45. Charter Oak lengthened the slide to 12 inches so you have 12 inches of dovetail contact. Next they increased the diameter of the circular plates the head swivels on to 12 inches, it really is thick and massive. BEEFY would not be an under statement. This should improve finish and accuracy.

By the way look at that motor on my mill closely, its a Leeson 3hp 3 phase inverter rated continuous duty motor. Sadly Leeson are manufactured in China now but its still a step up from the stock motor imo. The Leeson because its inverter rated has a shaft mounted fan vs the stock 3hp 3 phase motor which has an electric fan to try to keep it cool at low speeds. Charter Oak keeps a few of these Leeson Motors on hand for when they run out of the stock motor which was the case when they prepped my mill so I got the Leeson.

Now take a look at Charter Oak's revised CNC kit. Gone are the pulleys and belts and all that nonsense that proved unreliable and prone to failure on my old CNC mill. They are now coupling the servos directly to the ball screws. I also looked up those servos they are pretty neat, the encoder, servo drive, and controller are integrated into the servo. Brushless DC Servo Motors with Integrated Drive & Controller by Teknic The ball screws are rolled but P3 grade. I have yet to research further into their kit so I can't speak to the rest of the components.

One thing though, those servos are not flood coolant proof. Certainly the electrical connectors are not. Charter Oak says Teknic has not yet received their IP ratings for the servos. But recently I have backed off going flood coolant in any case. Cons include having to waterproof everything. You really need a complete top, bottom, side enclosure to contain the mess and at the end of the day you don't have a Haas like high pressure blast flood coolant anyway. So I'm going with an Accu-Lube system, its not a mist that fogs up the shop but a spritz, no mess, dry chips for the most part, easy clean up, no rank coolant tank, what's not to like.

I'm just now cleaning and inspecting the new mill. Not much to report as yet, I can tell you the table seems VERY flat. I have a precision ground 24 inch Starrett rule and I checked side to side, front to back, diagonally and man its dead flat I can't get a .001 feeler gauge in anywhere. If there is a gap its not visible to the naked eye and its in tenths.

[mhackney]

Hey MetDetect, why did you decide to go with the 12z and CNC kit rather than the CNC Turnkey machine?

I'll be starting to look for a beefier machine to augment my G0704 next year. I've taken a close look at the Tormach PCNC 1100, the Novakon Torus Pro and the Charter Oak IH Turnkey. They each have their strengths and weaknesses. Big Y travel is an important factor for me. Torus Plus wins here with its 15" travel. I live outside Boston so I plan to run down to Ct to look at the Charter Oak machines. I've seen the PCNC 1100 in operation first hand but I have not been able to see the Torus Plus. I do want to see and hopefully watch or use all of these before a final decision. My son goes to RPI so I am out your way a few times a year. Let me know if you give shop tours!

Regards,
Michael

[MetDetect]

Hey MetDetect, why did you decide to go with the 12z and CNC kit rather than the CNC Turnkey machine?

I'll be starting to look for a beefier machine to augment my G0704 next year. I've taken a close look at the Tormach PCNC 1100, the Novakon Torus Pro and the Charter Oak IH Turnkey. They each have their strengths and weaknesses. Big Y travel is an important factor for me. Torus Plus wins here with its 15" travel. I live outside Boston so I plan to run down to Ct to look at the Charter Oak machines. I've seen the PCNC 1100 in operation first hand but I have not been able to see the Torus Plus. I do want to see and hopefully watch or use all of these before a final decision. My son goes to RPI so I am out your way a few times a year. Let me know if you give shop tours!

Regards,
Michael

In spite of assurances I will not invest $7k into a CNC conversion again before I personally inspect and test the mill and I'm convinced it will meet my expectations. Worse case I plan to keep it as a manual mill and probably look at a used Haas mini mill or sell the 12z off at a minimal loss. Once you have $10k - $12k invested in a CNC'd bench top mill its more difficult to sell and not lose your shirt.

[SCzEngrgGroup]

If you're goal is to make parts, rather than make a hobby out of doing a conversion, you should simply buy a CNC mill from the start, like a Novakon or Tormach. I've done several conversions, and it always takes far longer ,and costs far more, than you think it will to do the conversion, and get all the bugs out to where it's a reliable production machine. I bought a Novakon Torus Pro almost two years ago, and since then I just out in the shop and make parts. The Novakon ended up being both cheaper, and better, than the conversions (which will now be sold at a huge loss, if I can even find a buyer).

Regards,
Ray L.

[MetDetect]

If the goal is to make parts vs hobby then I'd buy a real CNC mill with a tool changer e.g. a Haas or something similar. There's an old Haas VF1 on ebay now for $5,900, it runs now but if you put $6k into refurbishing it you're at $12k. Various used Haas toolroom and mini mills priced in the teens.

[SCzEngrgGroup]

My Charter Oak 12z just arrived. You can't appreciate just how big this mill is until you see it in person. That's a G4003G 12x36 lathe in the background, see the stainless toolbox next to it...the 12z is taller than that toolbox sitting on the floor. Its really pushing the definition of "bench top"..

You do realize Charter Oak IS Industrial Hobbies under new management?? They were, actually, he was, bought out about two years ago, and the former owner of IH is now a Charter Oak employee. What they are selling is the same basic machine, with a different CNC conversion. The larger saddle is the same as the mills sold under the IH name (and now several others sell the same machine).

IMHO, selling a CNC machine with a 3000 RPM spindle, and that cannot be used with coolant ,is kinda crazy. My machine has a 6000 RPM spindle, and even that is the biggest limitation on my throughput. 3000 RPM would be absolutely crippling.

Regards,
Ray L.

[MetDetect]

You do realize Charter Oak IS Industrial Hobbies under new management?? They were, actually, he was, bought out about two years ago, and the former owner of IH is now a Charter Oak employee. What they are selling is the same basic machine, with a different CNC conversion. The larger saddle is the same as the mills sold under the IH name (and now several others sell the same machine).

IMHO, selling a CNC machine with a 3000 RPM spindle, and that cannot be used with coolant ,is kinda crazy. My machine has a 6000 RPM spindle, and even that is the biggest limitation on my throughput. 3000 RPM would be absolutely crippling.


Regards,
Ray L.

Yes I am fully aware of this, I go way back with IH I'm talking 7-8 years ago. As for flood coolant fact is Accu-lube drop type (near dry) coolant systems are being use on large industrial VMC's at even higher spindle speeds.

[butthead]

MetDetect - thanks for all the excellent information. That's the kind of info I've been looking for.

My machine has a 6000 RPM spindle, and even that is the biggest limitation on my throughput. 3000 RPM would be absolutely crippling.

Regards,
Ray L.

Ray, what machine do you have?

[MetDetect]

Hey MetDetect, why did you decide to go with the 12z and CNC kit rather than the CNC Turnkey machine?

I'll be starting to look for a beefier machine to augment my G0704 next year. I've taken a close look at the Tormach PCNC 1100, the Novakon Torus Pro and the Charter Oak IH Turnkey. They each have their strengths and weaknesses. Big Y travel is an important factor for me. Torus Plus wins here with its 15" travel. I live outside Boston so I plan to run down to Ct to look at the Charter Oak machines. I've seen the PCNC 1100 in operation first hand but I have not been able to see the Torus Plus. I do want to see and hopefully watch or use all of these before a final decision. My son goes to RPI so I am out your way a few times a year. Let me know if you give shop tours!
Regards,
Michael

Lets talk Y travel. First the Charter Oak has 10.625 inches of Y or 12.250 inches depending on your point of view. If you crank the table out flush with the front of the Y axis dovetails it measures 10.625 inches to the column, subtract about .250 inch for the rubber way cover which is bolted onto the back of the table. To get 12 inches of Y travel they over travel the table off the dovetails 1.625 inches e.g. the table hangs out over the edge of the table 1.625 inches. There is nothing wrong with this, I did the same on my old mill and it works fine but its an important point there is not a full 12 inches of travel with the table fully on the dovetails. At one point they were advertising 30 inches of X travel, same story they were over traveling the table 4 inches. I believe they have since revised this back to 26 inches.

I don't know about any of these other machines but if I were you I would fully understand how they are getting whatever the advertised Y travel is AND where the head is in relation to that travel e.g. the amount of travel behind and in front of the spindle center line.

I used to live within 20 minutes of RPI but now I live 2,800 miles away on the west coast.

[SCzEngrgGroup]

MetDetect - thanks for all the excellent information. That's the kind of info I've been looking for.




Ray, what machine do you have?

A Novakon Torus Pro, a Novakon Pulsar, and a CNC'd 9x49 knee mill.

Regards,
Ray L.