The Charter Oak 12z bed mill discussion thread

Maker when you CNC one of those gear head mills and it runs full blast for hours on end trust me you will long for something more quiet. I also think a good point for us who have garage shops attached to our house is the noise others in the house will have to put up with. I had my old one in my basement and the noise came right up through the floor into the living room. Just my observations and 2 cents worth.
 
UPDATE: The Charter Oak mill still tops the list after pouring over umpteen mill choices the last week. Only found one that tempted me, a used Grizzly knee mill similar to the 9901 that is absolutely mint sitting in a guys garage for $2k but the price was the only temptation, it really doesn't meet my needs. I considered again going with a used Haas but damn they are smoking crack on their prices, not far off what the things cost new and its pretty easy to rack up thousands in repair costs on those things. A new Haas is out of the question.

THEN I got some information on the new improved Charter Oak CNC kit. I was already familiar with the old style kit, belt drive and problem prone been there and done that on my early IH CNC mill. The new style kit uses brushless servos with integrated drives and direct drive connection to the ball screws e.g. no belts. I'll need more information on this kit before I'm ready to pull the trigger on that but I'd order the mill today if the belt drive option was in stock, I'm waiting for an ETA on that.
 
When you get an ETA on that belt drive could you pass that along? It's on my upgrade list.
 
Update: In no particular order...

Manual mill...

1. Belt drive kits are still on back order.
2. 3hp VFD motor confirmed at 3,600 rpm, the shaft size is some custom metric size from the factory so retrofitting a Baldor, Leeson, Marathon may require turning the motor shaft. On the other hand if converting to belt drive you just machine the pulley to fit.
3. I did look around for inverter duty alternative motors, not cheap about $500 and up and nothing with the wide base mounting frame of the China motor.
4. They insure the mill for shipping with an outside company (not the freight company) and CO will deal with any insurance matters, if they can just send a replacement part they will, if the mill is half destroyed they will ship out a new mill.
5. The VFD is a Danfoss 3hp Micro drive, I checked pricing looks to be $380 to $420 for that unit. Of the $850 they charge for the VFD upgrade which includes installation, control pot, etc. that only leaves $450 to put towards another motor plus having the shaft turned down, machining an adaptor plate, bah I just decided to go with the China motor CO provides. If I upgrade to a better quality motor later I'm only out a few hundred. Also I have yet to find a better quality inverter duty motor that was 3,600 rpm like the China motor, they were all 1,800.


CNC Kit...

1. The newly designed kit includes servo motors that are pretty cool, but are not yet IP rated. CO thinks they are good to go for flood coolant but I pointed out the electrical connection which clearly is not, bottom line I would need to confirm this with the servo manufacturer.
2. All three ball screws are 20mm and rated P3.
3. The Y axis servo is now mounted on the back of the base vs the front. They machine the back of the base flat at the factory in prep for the servo so if you purchase the kit and install yourself is bolt on, you do have the drill/tap the holes.
4. CO assures me backlash is zero, if you machine a circle you won't see issues at the quadrant changes in axis direction it should be a smooth circle.
 
I wondered what that hole in the back of the base was for (as I was lifting it off the floor with the hoist). Figured it was for the CNC upgrade and it looks like I guessed correctly.

Oh, and the VFD has a RS485 cable coming out of it. I assume this for spindle control via CNC software?



coolidge said:
Update: In no particular order...

Manual mill...

1. Belt drive kits are still on back order.
2. 3hp VFD motor confirmed at 3,600 rpm, the shaft size is some custom metric size from the factory so retrofitting a Baldor, Leeson, Marathon may require turning the motor shaft. On the other hand if converting to belt drive you just machine the pulley to fit.
3. I did look around for inverter duty alternative motors, not cheap about $500 and up and nothing with the wide base mounting frame of the China motor.
4. They insure the mill for shipping with an outside company (not the freight company) and CO will deal with any insurance matters, if they can just send a replacement part they will, if the mill is half destroyed they will ship out a new mill.
5. The VFD is a Danfoss 3hp Micro drive, I checked pricing looks to be $380 to $420 for that unit. Of the $850 they charge for the VFD upgrade which includes installation, control pot, etc. that only leaves $450 to put towards another motor plus having the shaft turned down, machining an adaptor plate, bah I just decided to go with the China motor CO provides. If I upgrade to a better quality motor later I'm only out a few hundred. Also I have yet to find a better quality inverter duty motor that was 3,600 rpm like the China motor, they were all 1,800.


CNC Kit...

1. The newly designed kit includes servo motors that are pretty cool, but are not yet IP rated. CO thinks they are good to go for flood coolant but I pointed out the electrical connection which clearly is not, bottom line I would need to confirm this with the servo manufacturer.
2. All three ball screws are 20mm and rated P3.
3. The Y axis servo is now mounted on the back of the base vs the front. They machine the back of the base flat at the factory in prep for the servo so if you purchase the kit and install yourself is bolt on, you do have the drill/tap the holes.
4. CO assures me backlash is zero, if you machine a circle you won't see issues at the quadrant changes in axis direction it should be a smooth circle.
Click to expand...
 
is the belt drive kit sold through CO or ArizonaDave?

coolidge said:
Update: In no particular order...

Manual mill...

1. Belt drive kits are still on back order.
2. 3hp VFD motor confirmed at 3,600 rpm, the shaft size is some custom metric size from the factory so retrofitting a Baldor, Leeson, Marathon may require turning the motor shaft. On the other hand if converting to belt drive you just machine the pulley to fit.
3. I did look around for inverter duty alternative motors, not cheap about $500 and up and nothing with the wide base mounting frame of the China motor.
4. They insure the mill for shipping with an outside company (not the freight company) and CO will deal with any insurance matters, if they can just send a replacement part they will, if the mill is half destroyed they will ship out a new mill.
5. The VFD is a Danfoss 3hp Micro drive, I checked pricing looks to be $380 to $420 for that unit. Of the $850 they charge for the VFD upgrade which includes installation, control pot, etc. that only leaves $450 to put towards another motor plus having the shaft turned down, machining an adaptor plate, bah I just decided to go with the China motor CO provides. If I upgrade to a better quality motor later I'm only out a few hundred. Also I have yet to find a better quality inverter duty motor that was 3,600 rpm like the China motor, they were all 1,800.


CNC Kit...

1. The newly designed kit includes servo motors that are pretty cool, but are not yet IP rated. CO thinks they are good to go for flood coolant but I pointed out the electrical connection which clearly is not, bottom line I would need to confirm this with the servo manufacturer.
2. All three ball screws are 20mm and rated P3.
3. The Y axis servo is now mounted on the back of the base vs the front. They machine the back of the base flat at the factory in prep for the servo so if you purchase the kit and install yourself is bolt on, you do have the drill/tap the holes.
4. CO assures me backlash is zero, if you machine a circle you won't see issues at the quadrant changes in axis direction it should be a smooth circle.
Click to expand...
 
Yes! :)

Dave makes them for CO as well as direct customers. Coolidge and I are getting ours from Dave (Coolidge did all the leg work). Not sure one is better/quicker than the other.
 
Damn, it must be a tough life to constantly figure out how to throw big money around...hehheh :lmao::lmao:
Although it's good food for thought though reading about you rich folks...:))

Anywho...provided I get a response to email I think most interesting to me is a 932M....
Give or take listing for 2500 and have less Y-travel than the CO, but for that money I do have power-just-about-anything. All that is lacking is my (obvious) brainpower!
I can live quite comfortably with (only) 8 inches Y and the wife agrees wholeheartedly with that....:whistle::whistle:
On my 1640 I don't have much Y-travel and that didn't bother me so far....:nuts:
I can't argue a VFD though..that's super nice.

In my defence...coming from a Littlemachineshop mini mill...everything looks better when it weighs a bunch!

Feel free to call me a mentally challenged Dutchie now...I can take it....

John
 
John,

There are guys here throwing a lot more money around than I! :)

As I've said before here (and will continue to until someone tells me to shut up) you get what you can afford/fit/justify and to heck with everyone else. This isn't a contest (I hope).

I was inches away from getting a 932 as I've had pretty good success with it's little brother my PM25 (had a LMS mini-mill before that), but I don't need power down feed and what I really needed was the ability to work to a 12"x12" work envelope without having to reset the workpiece. Having 26" of X doesn't hurt either... :whistle:

So I popped for the slightly bigger machine. I really do like the VFD upgrade and use it a lot so can't complain about spending the $$ for that upgrade. :))
 
wrmiller19 said:
John,

There are guys here throwing a lot more money around than I! :)

As I've said before here (and will continue to until someone tells me to shut up) you get what you can afford/fit/justify and to heck with everyone else. This isn't a contest (I hope).

I was inches away from getting a 932 as I've had pretty good success with it's little brother my PM25 (had a LMS mini-mill before that), but I don't need power down feed and what I really needed was the ability to work to a 12"x12" work envelope without having to reset the workpiece. Having 26" of X doesn't hurt either... :whistle:

So I popped for the slightly bigger machine. I really do like the VFD upgrade and use it a lot so can't complain about spending the $$ for that upgrade. :))
Click to expand...

And I think you've made exactly the right decision, Bill.
In my case I already went a tad 'overboard' with my 1640 lathe and not that I don't have a specific budget for me it's, as of now, more messing around with the machines making a thingie here and there while others have alot of 'stuff' to produce, with an actual plan! I do not...:))
I do want a mill that doesn't try to walk over to my neighbour like most mini mills probably do so I'm going for lbs and nice colors....hehheh
I don't need powerdown feed either, no matter how professional that looks...:lmao:
Just looking at the 932 cuz of the price shipped and the table feed and head feed. Not getting any younger here and even though I pull levers for a living...don't wanna pull anything at home except my wife!
The table "work envelope" is absolutely no issue for me in my situation.
I would stay jealous about the VFD though....

John
 
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