Re: What Size Servo Motors?

I'm not sure how space constrained you are but an older bridgeport
will definitely be more versatile. I myself have a Shoptask which is
a 3-1 machine : mill-drill-lathe.

The lathe is handy, but there is a definite tradeoff in going with
this style machine. The biggest impact for me has been the lack of a
knee to move the table in relation to the spindle. There are add ons
(quadralift) that get around this, but by the time you add this, you
are well within bridgeport striking range.

If you are looking for mill-drills there are a couple of other
companies that you might want to take a look at :
www.grizzly.com
www.use-enco.com

Grizzly has similar machines and tooling to harbor freight, but it
has been my experience that they have a slightly better fit and
finish worth the extra pittance. I would strongly recommend that if
you go mill-drill you get one with an R-8 taper on the spindle as
tooling is much cheaper.

My Shoptask came from the factory with nema 34 mounts for steppers
and was relatively easy mechanically wise to mount my motors to. I'm
still messing with tuning it up for proper operation, but I have made
my first nc cuts with it without too much modification. I'd say the
cost of the motors and controllers and various sundry bric-a-brac to
get it goin has cost me around $900 for 3 axis servos. I'm still
trying to decide which CAM software, but after some demos I am
seriously leaning towards visual mill + rhino. I currently use rhino
and its great. The demo of visual mill is quite impressive. $1500
sounds like a lot for the pair, but the difference between a real
company's commercial product and some of the hobby stuff is readily
apparent.

As for servos versus steppers. I have gone servos, but I'm not quite
fully operational so I can't speak to sizing them until I get mine
working! ;) If you look through the archives for mill-drill cnc
conversion you will come across a guy's sight who has complete plans
and sells motors to convert these guys. I think it was something
like home-cnc.com, but I don't have it handy.

BTW When searching through the archives it will only search the most
recent month, but on the page you get links from if you click "next"
you will get the previous month. This allows you to go back in time
and search previous months.

HTH

-Erik Reikes

--- In CAD_CAM_EDM_DRO@y..., "natchamp_87" <mark@h...> wrote:
> I am new to the list and have a couple questions and need some high
> level guidance. My plan is to convert a mill (which I haven't
bought
> yet) to CNC. The mill will either be an older Bridgeport type or a
> smaller bench type. Thanks in advance for any help.
>
> 1) If I go with servo motors because of the higher torque at speed
> and the continuous feedback. A) what size servo motors should I be
> looking for? Are there any other things to look for, or keep in
mind
> with a servo setup? Are there any good sources for used ones?
>
> 2) Am I assuming correctly that the Harbor Freight import type of
> bench top mills are significantly inferior to the older models? I
> don't really need the size of a Bridgeport and have space
> considerations. Any recommendations?
>
> Mark