Re: [CAD_CAM_EDM_DRO] has anyone built a 4x8 CNC router?

I am building one and it is costing about $2K

----- Original Message -----
From: <JanRwl@...>
To: <CAD_CAM_EDM_DRO@yahoogroups.com>
Sent: Sunday, August 08, 2004 8:33 PM
Subject: Re: [CAD_CAM_EDM_DRO] has anyone built a 4x8 CNC router?


> In a message dated 8/8/2004 2:25:54 AM Central Standard Time,
> mjmautoinnovations@... writes:
> Has anyone built a 4x8 CNC router?<<
> I did a 5x10. NEVER again! TOO Much work, and NOT enough money! There
are
> "store-bought" X-Y machines that size for less than MY cost for materials
and
> parts, NOT including my "labor"!
> I am hoping to build one cheaply.<<
> This would be akin to building a new luxury automobile at home for $5000.
> I have a pretty good idea if what I want to do. But, I am unsure about a
few
> aspects. For example leasdscrew sizes, stepper sizes" &". <<
> Only 4x8? "Professional rapid-traverse rates", or slow as a box-turtle?
It
> MAKES a difference! If you use preloaded ball-screws, one with at
least
> 1.3" major dia. would be needed for the 8' axis, if not 1.5 inches. To
turn
> that and move a gantry of the size/weight I'd expect you would be doing,
you
> would need a good Size-42 stepper with "chopper drive". For the
"Y-screw", I'd
> STILL use at least 1.3" dia. A triple-stack bipolar "KML-093-nnnn"
stepper by
> Superior Electric would possibly do if your machining is fine, and you use
> proper bearings, well-aligned. For the longer X-axis, that goes without
saying!
> Do NOT expect to support "the motor-end" of the screw by the
> motor-shaft/bearing! Use DUAL "fixed" angular-contact bearings at both
ends of BOTH screws,
> and a proper "no slop" (aka "no backlash") coupling connecting one end of
the
> screw to the resp. motor.
>
> Take it from me: When you go to the Stepper and Driver store, take MONEY!
>
> If you think you can do this with ACME screws and preloaded Turcite
bearings,
> one or both of TWO things will come to your attention: You may need
LARGER
> motors (to overcome the friction) than you expected, and/or your SPEED of
> traverse will be reduced.
>
> Sounds all negative and nasty, doesn't it? Lotsa luck. HOPE you can
prove
> me wrong. Been nearly two decades, now, since I had finally discovered
what it
> means to say, "Been there; DONE that!"
>
> Jan Rowland
>
>
> [Non-text portions of this message have been removed]
>
>
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