Re: [CAD_CAM_EDM_DRO] Re: Electronic Lead Screw & Power Cross Feed | Poor CNC ?

now a turret for my taig - THAT's got my interest for
sure!
soon as i get one of these suckers CNCed i'll
definitely be looking into that.
but! in some weeks or months i'll be able to report
real numbers on what it cost to cnc a little taig!

it's only just in the beginning stage now...but i have
11 of em i'm doing this to.

--- "C.S. Mo" <cs@...> wrote:

> >grr...that's the problem with analogies. i put my
> foot
> >in with analogies, but i'm not gonna now immerse
> >myself...lol
>
> Don't feel bad.. I'm sure all the people driving
> cars *wish* they were
> flying planes. Particularly during rush hour. :)
>
> >i suppose you Can spend as much as you like to cnc
> a
> >500$ lathe...but i question the assumption that
> $2000
> >is the mean, average or normal figure - for a
> desktop,
> >certainly.
>
> My $2,000 figure was based on components for my 9x20
> lathe..
>
> 2x Stepper/Servo motors @ $100 ea.; $200
> 2x Gecko G2x0/3x0 @ $120 ea.; $240
> 1x Power Supply @ $150
> 1x PC w/Monitor @ $250
> 1x Parallel Port Breakout @ $50 (could be twice
> that)
> 1x Ballscrews @ $300 (this item could be debatable
> and is probably more
> expensive)
> 1x Replace single phase spindle motor w/3 Phase @
> $75
> 1x VFD @ $175 (so I can control spindle speed)
> 2x Timing Belts, Pulleys..etc @ $30; $60
> 1x Limit switches, wiring, misc @ $100
> 1x Replace bearings and re-design motor mounts to
> control backlash @
> $100 (probably more)
>
> Total: $1,430
>
> So, less than $2,000 but still quite a bit. And no,
> I don't want to
> debate the exact dollars - depending on what and how
> you buy, you could
> be quite a bit higher or lower. But I suspect that
> in general hardware
> will run around $1,500. And even then you still have
> a relatively crappy
> CNC lathe. (No power tailstock, no turret, no easy
> way to setup a
> barfeeder..etc..etc. However, those items may not be
> important in this
> class of machine.)
>
> And yes, a Sherline or Taig would be much cheaper.
> Probably more like $5-700.
>
> >i don't see how you can synchronise lead screw and
> >spindle significantly cheaper or with less
> enjoyment
> >than full cnc, at least on a desktop lathe like a
> taig
> >or sherline. until the motors are in the hundreds
> >dollar range, they arent the main cost of such a
> >project.
>
> Well, let's see.. Assuming you can get the control
> for $150, you still need:
> 1x Motor @ $100
> 1x Power Supply @ $125
> 1x Sensor of some sort to provide feedback on
> spindle speed @ $10
> 1x Timing belts, pulleys..etc @ $30.
>
> You probably don't need to worry about backlash
> since you're probably
> only going to be cutting in a single direction. You
> don't need to worry
> about controlling spindle speed since you're only
> going to be cutting at
> a single diameter (unless you have those really
> special DEEP threads),
> you may or may not worry about limit switches, you
> probably don't need
> ballscrews since you're only worried about accuracy
> over relatively
> short distances.
>
> Total $415 - despite what I said before.. At $415,
> I'd probably just go
> on with my manual turning..... However, since you're
> probably not too
> concerned with rapid speeds, you could use a smaller
> motor and gear it
> down more, so $50 for the motor, which would let you
> use a much smaller
> power supply, so $50.. At $290 it starts to look
> attractive to me again
> although that's still a bit high just to do
> threading.
>
> >i question the assumptions made regarding all the
> >difficulties of CNC. if you want to design a
> circuit,
> >you can go ahead and master orcad or altium...use
> your
> >scope and soldering station to wire up a
> >breadboard...or etch your own pcb...or create the
> >files and send out $ for one...then you can test
> your
> >board, but you still have to cnc an axis PLUS
> encoding
>
> The capabilities of your axis don't have to be as
> good as for CNC.
>
> >as well as the spindle encoder. well, those 2
> things
>
> You don't actually need a spindle encoder - you just
> need a tach.
>
> >have to happen for full cnc anyway, so that's even.
> >so you are trading off the shelf parts for a pcb
> >design project to test (and will probably work
> without
> >much tweaking) and to avoid the agony of attaching
> a
> >stepper to the existing cross-slide screw and a
> 100$
> >tablet pc to give you EvErYtHiNg you can gt by
> >designing a 'less than' circuit...and lots
> more...of
> >course, if you were to do an electronic
> spindle/lead
> >synch, yu'd get a chance to do a lot of lovely math
> >fun! but you can get that with cnc, too if you
> wanna
> >do it the hard way..
> >
> >so that is not an effective trade (for me, with my
> >skills, for my purposes) but then, i already know
> >gcode consists mainly of the line and the arc and
> is
> >sooooo not a hairy deal to put any effort into
> >avoiding it...i already know all about designing a
> pcb
> >so there is no great joy or novelty in that for me
> and
> >i'll happily put my effort into what i see gets me
> a
> >better return for marginally larger cost.
> >
> >i further question the assumption that $150 is the
> >full and complete expense for developing the
> >synchroniser. unless your wage is normally under 2
> >digits and on the RIGHT side of the decimal point,
> >your time is gonna have to count...
>
> I don't think anyone is thinking they're going to
> make money making this
> board. But then, I could be wrong about that!
>
> >my cnc machines all have handwheels, btw. there's
> an
> >assumption i outright reject. i use manual or cnc,
> as
> >i please..
>
> Don't let Ballendo hear you say that! (Although I
> happen to agree.)
>
> --C.S.
>
>
>
>
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