RE: [CAD_CAM_EDM_DRO] need advice

Hi Ray

I see no reason why it should not be convertible, many on these groups have
converted much smaller DIY mills with good success, small cut limitations
but viable machines.

Being a knee mill it looks commercial strength, be a little cautious though
that it is strong and rigid enough to do the machining work you need. There
are many small DIY mills that are not very rigid or accurate.



Have you thought about converting and older mill with faulty CNC, there are
many around at very low prices, the motors, ball screws etc are all mounted
and sized for the machine, and you can get a commercial strength machine (if
you can fit it in your home shop). You'd probably find one for a quarter of
the price of your grizzley, and commonly with a lot of tooling as well.

To convert the grizzley you are going to need ball screws, which will be
expensive if you want a fairly high tolerance screw, be aware there are many
DIY ball screws with 3 to 5 thou backlash, a commercial machine lead screw
is normally better than a half a thou backlash, and much more expensive.
Don't expect to rely on antibacklash softare if you want to mix climb and
conventional milling, they each require different techniques that are not
really properly allowed for in the software anything close to permit you to
think it can bring a sloppy screw up to an acceptable commercial ball screw
standard.

Motors, many DIY people will use cheap small steppers and they get a machine
that works reasonably well, but steppers are all not easy sailing, and there
will be problems like resonance at some speeds. Most commercial machines use
DC or AC servos and give a much better response, big servo's are not without
probems. At present we have a lack of good cheap step/direction servo cards,
there are some unproven newcomers that look promising, or you can use the
original analogue cards with pixie converters.

As to software, the are two man groups, those than run Lynux and those that
run Windows based systems. Presently I am a windows / mach3 user.

Controls, some of us use the PC parallel port with a breakout card, and the
software for this is well sorted with mach3, but IO ports are a little
limited in number, some of us use other proprietary CNC controllers, the
main one which is just about viable now in Mach and which has taken over a
year to get the software to that point is the G100 from Gecko, but there are
others on the market.



Anyhow that gives you a lot to think about. Try also joining the
mach1mach2cnc group and perhaps the gecko group on yahoo where you will pick
up a lot more.from many people doing conversions though this group would be
the unbiased one. Lastly don't jump in and buy bits unless you have
thoroughly discussed the possibilities on this group, there is an awful lot
of DIY grade kit out there that will work for some people, and for others
just cost you time and money with no result. I speak from experience here.



Regs Mark



Dr. Mark Vaughan Ph'D. B.Eng. M0VAU

Managing Director

Vaughan Industries Ltd, reg in UK no 2561068

Water Care Technology Ltd, reg in UK no 4129351

Addr Unit3, Sydney House, Blackwater, Truro, Cornwall, TR4 8HH, UK.
Phone/Fax 44 1872 561288

RSGB DRM111(Cornwall)

_____

From: CAD_CAM_EDM_DRO@yahoogroups.com
[mailto:CAD_CAM_EDM_DRO@yahoogroups.com] On Behalf Of Ray
Sent: 14 June 2007 15:45
To: CAD_CAM_EDM_DRO@yahoogroups.com
Subject: [CAD_CAM_EDM_DRO] need advice



Thank you for allowing me to join your group. I am a mechanical
engineer who worked his way through collecge as a tool and die maker.
I now program 3 cnc routers. I use master cam, komo router cim and am
very knowledgable with g-code.
I would like to have a cnc machine at home. I enjoy building steam
engines.
I would like to buy a table top knee mill (G3102 grizzley.com) and
convert it to cnc. I am buying this size because of the size of my
shop.
I need help converting this mill. Is this a good mill to convert? What
do I need? break out boards, power supplys, steppre motors ect. I
would like to replace the motor with a DC motor so I can get computer
controled varable speed without having to change belts.
I would appreciate any help you can give me
thanks Ray Mahlberg





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