Re: [CAD_CAM_EDM_DRO] Taig CNC or Sherline CNC?

Ballendo -

Agree with most of your conclusions below. A couple of points though:

- I would avoid the temptation to use motors of less than 200 oz-in with
the Taig mill. The original spec was 140 oz-in (my mill had these to start
with); this was only just adequate. Since the re-design of the Taig Z-axis
to use box section ways, you need 200 oz-in to handle the Z axis, and the
extra torque much improves the X and Y, allowing you to use the machine to
take the heavier cuts that its (relative) rigidity will allow.

- The Taig bi-level chopper drive is OK as far as it goes (and mine still
goes just fine, although it is soon to be replaced with a microstepping
drive); however, they have chosen to use relatively high voltage steppers
(the 200 oz-in steppers are 1A/phase), so this is part of the reason that
they need to use 55V for their high level supply. Hence, if you are going
the Xylotex driver board route, you will be better off NOT using the Taig
motors at all, and instead choosing 200+ oz-in steppers that have a current
rating nearer the 2.5A/phase capability of the driver board.

Regards,
Tony

At 19:53 27/01/2004, you wrote:

>Hello,
>
>As with the previous posted replies, I think you'll be happiest if
>you combine the two machine's strong points.
>
>Since you want to use EMC, use the Sherline electronics, which are
>already set up for EMC.
>
>Use the taig mill. Here I'm gonna depart from the other two replies
>and say to use the WHOLE sherline head/spindle/motor. And mount it to
>the Taig XYZ mill base. My main reason for this is that I believe
>Sherline has a better (much,IMO) range and quality of spindle
>accessories. Another is in the PS at the bottom of the msg.
>
>So for the easiest plug-n-play, I'd buy:
>
>1)Taig cnc-ready mill, without motors and headstock.
>
>2)Sherline headstock and motor (You may also want the 1297 mill head
>spacer block- you will need the mount pin for the headstock--you can
>see it in the 1297 picture. There are two types. One has a flange,
>and the other has a tapped hole. You want the one with the tapped
>hole. It has a 1/4-20 thread, so it will be REALLY easy to mount the
>sherline head to the taig body)
>
>3)Sherline motors and control/software
>The Sherline motors are 135 Oz. in. driven by a unipolar chopper at
>24 volts, with a 4A power supply. The drive has quad microstepping
>for smoothness. One reason to use the sherline drive system is that
>it's already set up for the Sherline rotary table; which everyone
>agrees is the best for the money on the market. Another possible
>advantage is that with 4 drive channels; if one should fail for any
>reason on a friday night, with part due monday you might be able to
>swap cables and get your work done...
>
>Against this the Taig motors are 200 oz. in., and their drive is a
>bilevel type (they engage in what I feel is a bit of "marketing" in
>their description of it as a bilevel "chopper" drive.) No specs for
>the power supply amps, but the hilevel volts is 55, and they claim
>30IPM travels. which is believable, and bilevel drives DO have their
>advantages... But only 200steps/rev, which means it may be prone to
>mid-range resonance. Owners of that system will have to guide you
>here.
>
>If the Taig motors will work with the Sherline drive, I'd probably
>use 'em. But now we're beginning down the slippery slope... Up to
>now, everything has been pretty plug-and-play, out-of-box. One 1/4-20
>tapped hole notwithstanding<G>. Once you start down this path, it can
>get complicated fast. If you use the taig motors, you'll need to put
>new connectors on 'em for the sherline control, for example. OR...
>
>At that point...
>
>Why not use the DenverCNC control box? At 475 bucks, it's
>significantly less expensive than the Sherline, and uses a Xylotex
>drive board which will be capable of giving faster axis travels with
>EITHER the Sherline or Taig motors, Much faster. As a /8
>microstepper, it will also be smooth. And it also has 4 axes, so you
>don't lose any of the "Sherline" advantages mentioned above. It's a
>bipolar drive, giving you additional motor options for the future.
>But again you'll be reconfiguring the connectors of the motors. FWIW,
>I WOULD use one of the two motors mentioned, taig or sherline, to
>start with.
>
>Side note: I understand the DenverCNC box is being refitted with
>drives based on the lmd18245 chip. (not sure when this new model will
>begin shipping) At 3A and 55V; this is really one of the better
>stepper driver chips available. If they can hold their price point,
>the DenverCNC box will be perhaps the best value in a Desktop CNC
>driver unit.
>
>So, the first setup above is the plug-n-play best, IMO.
>
>But the overall BEST (But requiring more work on your part) would be:
>
>1)Taig CNC XYZ mill base with motors. No head, driver/controller, or
>software.
>2)Sherline head, mount pin, and maybe #1297 spacer plate.
>3)DenverCNC control/driver box- they sell cables too, but I don't
>know which connectors, so I can't say whose cables might be best. BUT
>its a good bet that Sherline's will be available for a LONG time...
>4)The sherline EMC software pkg.
>
>Now You've got a 40IPM-plus, robust CNC mill, with excellent tooling
>capabilities and also sherlines excellent software/product support.
>
>Hope this helps,
>
>Ballendo
>
>P.S. One thing not immediately apparent is that with the Sherline
>head capability to be rotated on its mount pin; angled holes and
>features can be milled. Using CNC to interpolate the otherwise hard-
>to-do interaction of the z and y or x. Taig mills can tilt their
>column, but as the pivot is at the base (like the minimills), it can
>be pretty hard to reach some features on your part.
>
>P.P.S. Although Joe Vicar says he's working on a version of his
>toolchanger for the Taig, the one he has NOW is based on the
>Sherline... worth keeping in mind, IMO.