Re: [CAD_CAM_EDM_DRO] Knee for z-axis control?

Stephen Wille Padnos wrote:

>Jon Elson wrote:
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>
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>>Stephen Wille Padnos wrote:
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>>>I'm not sure a counterweight system would work. You'd need a cable that
>>>goes over the top of the machine or something - this would probably get
>>>in the way of the machining envelope.
>>>
>>>
>>>
>>>
>>No, you could mount some bars near the top of the knee that project back
>>a few inches
>>past the ways to the side of the column. That area is not usable for
>>workspace
>>anyway. The pulleys could be mounted to the big bolts that hold the turret
>>
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>>from turning. If you put garage door springs above the weights then
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>>even the
>>increased mass would not be much of a concern.
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>Ah - I see. Of course, that would get in the way of my control cabinet,
>which I intend to mount on the side of the column :) (I could do it on
>one side, though)
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>

Well, you'd only need for the control cabinet to be set back a couple
inches from
the ways. Then, the cable/chain could go up and over the cabinet.

>
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>I have no intention of doing anything other than possibly adding a power
>drive to the knee on my machine. The only advantage I've seen in this
>discussion is a longer Z travel under CNC, which isn't important to me
>(yet). I may modify one of my manual pulse generator cards to allow me
>to move the knee a specific distance, but I would still re-zero after
>the move, since I wouldn't trust it to be accurate enough.
>
>

Well, I have my head trammed in pretty well, and I often move the knee 8-12"
up or down to adjust for tool length, and don't reset the X and Y axes.
They are
still well within tolerance to tap a hole or whatever.

Jon