RE: [CAD_CAM_EDM_DRO] Re: CNCing a small lathe

The most widely used CNC control program is probably Mach 3:
http://machsupport.com/ , but there are others. You can download and install
Mach 3, it is fully functional but has a 500 line limit until it is
licensed. Most CNC control programs will use the parallel port, although
there are motion control boards with USB/Enet interfaces such as the
SmoothStepper: http://soigeneris.com/Warp9.aspx . You’ll need a stepper
driver, the Gecko G540 is a good choice for small machines as it has
everything built into it (such as Breakout board, all signal opto-islated,
etc). You can also get complete, plug-and-play drive boxes such as:
http://soigeneris.com/CNCPartsPage4.aspx (disclaimer: my website), and many
other types are available.



Just about any machine tool you get from Harbor Freight should be considered
a ’kit’, the fit and finish is horrible. Grizzley sells machines that look
to be the same identical design but are of high quality (still not on par
with USA made equipment). I suspect that on either one you’ll wind up
replacing the lead-screws eventually with something with far less backlash
but I think the Grizzly screws are likely to be better. (Just my opinion
from having the opportunity to visit out local Grizzly and HF stores.)



Sizing stepper motors is dependent upon the pitch of lead-screws, any
gear/belt reduction you add, the drive friction of the machine, and your
desired feed rate. When choosing stepper motors bigger is not always better.
Having the steppers be a good fit for the drivers, power supply and machine
is the key.



Before getting caught up on the size of the machine tool ask yourself what
it is your wanting to build with it. If your wanting to gain some experience
with a CNC lathe you might want to consider something like a CNC ready
Sherline lathe. It is small but quite capable and would let you get started
learning how to use a CNC machine without fiddling with the mechanics. Once
you get some experience with a smaller machine you may decide to convert a
larger manual machine and then you can use your small lather to make parts
for the bigger one.



Just some thoughts…



Jeff Birt

Check out – Soigeneris.com…



From: CAD_CAM_EDM_DRO@yahoogroups.com
[mailto:CAD_CAM_EDM_DRO@yahoogroups.com] On Behalf Of Mike Hagen
Sent: Monday, July 05, 2010 12:21 PM
To: CAD_CAM_EDM_DRO@yahoogroups.com
Subject: Re: [CAD_CAM_EDM_DRO] Re: CNCing a small lathe






I am new to the list. What PC programs are hobbyists using? Serial
port output?
Are there some that I can try with just some steppers set up?
I see all the homemade stuff but not much mention of what is used at the
PC end?

The Harbor Freight small 7" Lathe is on sale for $399 in a flyer I got
(7X10" #93212). Looks awfully small?
Does it got good enough lead screws and quality to make it worth
spending time on it.
What size steppers are suggested?
The 8" online is $699 (#44859).

On 7/5/2010 4:50 AM, Ron Ginger wrote:
>
>
> > Posted by: "turbulatordude" dave_mucha@...
<mailto:dave_mucha%40yahoo.com>
> <mailto:dave_mucha%40yahoo.com> turbulatordude
> > Date: Sun Jul 4, 2010 9:22 am ((PDT))
> >
> > seems like a small lathe. the 7x lathes seem to be less expensive,
> larger (not by much) and CNC'd all over the net.
> >
> >
> The 7x are common, but take a look at the Harbor Freight 8x12. Its just
> $50 more but a MUCH bigger machine- the 7x weigh under 100 pounds, the
> 8x12 is 225 lbs.
>
> I just did one, I showed it at the recent CNC workshop. I will try to do
> an article on it on my web pages. It was a very simple conversion and
> works well. I did not do a tool turret, Im just using an aloris tool
> holder and I manually switch tools- fine for my needs.
>
> Mach works just fine with a single pulse on the spindle and I was able
> to make a real neat pickup inside the headstock casting.
>
> I have started a new set of lathe wizards for Mach which were well
> received at teh CNC workshop. Hopefully before summer is over Ill have a
> release.
>
> ron ginger
>
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