Re: 9x42 conversion

Hi, I was looking over your web site on the comet cnc
conversion...Very cleaver arangment to use the old handwheels...But a
few things i do not understand about it...You say you used taper
roller bearings on the ballscrew and put them in the old handwheel
housing??? How in the world did you do that...I looked for tapered
roller bearings for 17 or 20mm shaft and could not find any...And if
you did find these how did they fit in the old housing...

I would love to see a drawing of how the screw, bearing, and housing
fit together.


Wally

--- In CAD_CAM_EDM_DRO@yahoogroups.com, "C.S. Mo" <cs@v...> wrote:
> I don't know very much about steppers - I used Servo's to convert my
> Comet 10x50..
>
> <http://www.smidgie.com/928/machineshop>
>
> I used Reliance Electric E712 servos with Gecko G320's. The motors
are
> rated for 300oz/in continuous, 1,500oz/in peak (limited to about
750oz/in
> peak with the G320's). I'm using a 2:1 reduction, 5tpi ballscrew.
>
> Using Mach2 on a 600mhz PIII, I'm running it with 105ipm rapids..
With a
> faster PC, my rapids could be a bit better.
>
> I think that once you get into a Bridgeport size machine, steppers
are
> not that much cheaper than servos. At least that was my personal
experience.
>
> --C.S.
>
> >
> >
> >Thank you Ron. Servo's is a strong consideration. Do you
> >know of a good source for the motors, or should I just look
> >around.
> >I have thought about driving the knee also, but I figured
> >the accuracy of the whole knee dovetail and the gears would not be
> >very accurate. I guess it is accurate enough for the Z axis
> >especially in light of the fact that the axis does not see a large
> >range of motion in most machining operations.
> >Can I ask you what kind of items you mostly machine?
> >
> >Thanks,
> >Scott