New Charter Oak 12Z on the way

I actually prefer this style bed mill to a knee mill and the Y travel on most knee mills is around 9 inches vs 12 for this mill. I have looked at some used industrial bed mills which dwarf the CO but like you I'm not really looking for a 4000 pound beast. I can lift the CO with my tractor front end loader, its not so heavy that I can't put in on wheels so I can shove it out of the way when I need to. I have a Grizzly G4003G 12-36 lathe and it seems every time I turn around I need a mill for some operation.

Oh yea, a 4000G? That's on my short list for my next lathe. The other is the Eisen 12x36. Taiwan made but a bit pricier. Money no object is the PM1340GT.

Are you going to counter weight the head? I counter weighted my old Rong Fu and will do the same with the CO if I purchase one especially since the spindle sticks out 12 inches from the column, those gear heads plus the motor is a lot of weight pitching forward.

This mill design begs for a counterweight. My friend's big CNCs are counterweighted, so why not these? Cost, probably. Once I get the mill I will look at my options in this regard. I won't power the head, as I like to use the Z axis for precision placement using a 3-axis DRO as opposed to using the quill. Unless I'm doing a plunge cut. This is where I miss having a knee mill: when I can move the part into the cutter on Z. But then...if I counterweight such that the Z axis screw is always preloaded the other way, i.e., the counterweight is heavier than the head (opposite of the loading on a knee), I could do pocket cuts without having to use the quill. I'll have to think about this. Probably will depend upon how robust the column is.

I thought the price of the CO was quite reasonable compared with Grizzly and others. Shipping to me on the west coast is brutal, the quote is about $560 ouch!

Yea, shipping to me was $529. Eisen quoted me about $450 to ship a 12x36. Guess these guys don't get the volume discount like Grizzly does...

Bill
 
Are you going to counter weight the head? I counter weighted my old Rong Fu and will do the same with the CO if I purchase one especially since the spindle sticks out 12 inches from the column, those gear heads plus the motor is a lot of weight pitching forward.

Hi
Have you any photos of the counter weighted, love to see them.
 
I am hoping so (that it's a great machine), but being somewhat a realist, I am sure there will be warts. There always are on these class of machines. I'm just hoping that the process that Paul described to me mitigates the bigger ones.

But then again I'm one of those oddballs that actually enjoys tweaking, tuning, and making mods for my machines. I am NOT expecting the quality of a Hardinge HLV or that of a new BP in a $2400 mill. ;)

Bill

Bill, congrats on the new machine. Please be sure to post up a bunch of pictures and a detailed review once you get it. I am curious as the number one thing I liked about this machine when I saw the specs was the 12" Y-axis travel. Only one in that size/class that has over 9" in the Y direction.
 
Hi
Have you any photos of the counter weighted, love to see them.

No but it was a simple counter weight consisting of two overhead pulleys, some 1/4 wire cable with several 50 pound sand bags as counterweight they sell on the east coast for adding weight to the back of your truck for traction in the snow.
 
No but it was a simple counter weight consisting of two overhead pulleys, some 1/4 wire cable with several 50 pound sand bags as counterweight they sell on the east coast for adding weight to the back of your truck for traction in the snow.

Hi
Is the weight to help with the up & down of the head.
I would think the weight would help the cutter, ????
 
Hi
Is the weight to help with the up & down of the head.
I would think the weight would help the cutter, ????

Counterweighting reduces the loading on the Z-axis screw, and helps with positional consistently. It also reduces the forward strain on the vertical column. The larger CNCs I have seen all have counterweighted heads.

Bill
 
Hi
Is the weight to help with the up & down of the head.
I would think the weight would help the cutter, ????

The weight of the head plus the motor plus the leverage involved with the head sticking out so far from the column puts a lot of stress on the ways imo and should be counter weighted. In the case of my old IH CNC mill the stepper they used could not handle the load. Even counter weighted it would lose about .040 inch on every upward movement on Z, in 1-3 moves the thing was out of whack over .100 inch. The phrase utterly useless comes to mind, don't get me started on that thing. lol
 
Bill, congrats on the new machine. Please be sure to post up a bunch of pictures and a detailed review once you get it. I am curious as the number one thing I liked about this machine when I saw the specs was the 12" Y-axis travel. Only one in that size/class that has over 9" in the Y direction.

I plan to Mike (post pictures). :) I've been asked by others to take some pictures and write about my observations on this machine. And like you, the Y-axis travel and the head/column interface were the things about this machine that caught my attention.

Last night I received a picture of a 12Z mounted on a stand and sitting in a rather large shop. Wow, this thing looks massive. I sure hope it fits in my tiny little shop! Yesterday when I checked tracking, the estimated delivery date is this Friday. We shall see. I'm having the 220 run to the garage this afternoon. :))

Bill
 
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I plan to Mike (post pictures). :) I've been asked by others to take some pictures and write about my observations on this machine. And like you, the Y-axis travel and the head/column interface was the things about this machine that caught my attention.

Last night I received a picture of a 12Z mounted on a stand and sitting in a rather large shop. Wow, this thing looks massive. I sure hope it fits in my tiny little shop! Yesterday when I checked tracking, the estimated delivery date is this Friday. We shall see. I'm having the 220 run to the garage this afternoon. :))

Bill

Awesome. Sounds great Bill, I'm happy for ya.
 
I'm now looking at the Grizzly G0720R or G0722 in comparison...soul searching do I really need 12" of cross travel and 3,000 rpm if I'm honest no I won't be doing production work on the thing. If I have a larger work cube job and the need for speed I can throw that job to a local shop with an industrial CNC mill that will spit it out in a fraction of the time it would take on either of these home shop machines. What I like about the Grizzly is the quiet belt drive brushless DC motor, less expensive plus I have a 10% off coupon and the shipping is $150. Decisions decisions.
 
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