[Mark Scrivener]

Hello,

After years of using my Taig lathe, doing what I can with the mill attachment, and running over to a friends house to use his mill, I've decided to get my own mill - and to make it CNC.

My application is hobby stuff...primarily gauge 1 live steam locomotives (modifications, some scratch building). But I have plenty of other hobbies that could benefit from this tool. For the live steam most of the work is in brass (360), but some steal.

There will be times when I want to make a dozen or more of a particular part, and times when I need to cut a complex shape (2D out of flat material), so CNC is a big plus. I already have a computer set aside and have been playing with the demo versions of Mach 3 and Alibre's CAD/CAM.

After doing a bunch of research, I decided to go with the Taig mill. My dilemma at this point is do I purchase the complete CNC mill from Taig (well, probably Nick Carter), or the CNC ready mill? The price difference is $1339. A Geko 540 controller and 4 motors is $500 or less. Are the controller and motors from Taig that much better? What am I missing? What controller/motors should I consider? I don't need insane slew rates or stepper resolution that is 1000x better than the mill, but I don't want the electronics to be the limit.

Thanks!
Mark

[jalessi]

Mark,

The G540 and the Keling KL23H284-35-4B 387 oz-in steppers are awesome with the Taig.

http://www.kelinginc.net/KL23H284-35-4B.pdf

Get the 48 volt power supply to go along with it and you will be a happy camper.

KL-350-48 48V/7.3A 110V/230V $59.95

You will not measure any performance gain with the Taig supplied equivalent. Spending an additional $500.00 is a complete waste of money.

The Taig equivalent is integrated into a chassis and comes pre-wired, if you are handy you should be able to do the wiring and mount the component parts in less than a day.

Do yourself a big favor and save the $500.00

Jeff...

[jalessi]

Mark,

P.S.

If you plan an running a fourth axis in the future spend the extra money for the 12.5 amp power supply its a little overkill however you cant beat it.
KL-600-48 48V/12.5A $139.95

Jeff...

[TOC Admin]

Mark...take Jeffs advice, The Gecko g540 is the way to go.....!

[Crevice Reamer]

The Taig leadscrews are 20 TPI, so with this gearing, you don't need big heavy motors. This combination will run 4 motors with only the 7.3A PSU:

Just bolt on the motors, wire some motor cables with the supplied connectors, connect 2 wires to power supply, and plug a parallel cable between the G540 and the computer and you are ready to go. Mach3 trial version is free.

http://www.taigtools.com/mmill.html

http://geckodrive.com/product.aspx?c=3&i=14469

(2) http://kelinginc.net/KL23H256-21-8B.pdf X and Y motors

http://kelinginc.net/KL23H276-28-4B.pdf Z motor

http://kelinginc.net/SwitchingPowerSupply.html

Keling also sells the G540, so you can get all of the electronics in one place.

G540 $299, 3 motors $105, PSU $60.

Total cost of electronics is $464

Taig 2019CR $1156

CNC ready mill plus electronics: $1620.00

Mach3 $175--Less if you buy it from Keling with motors.

Easy cam program integrates with Mach 3 and allows part design and gcode generation for $69:

http://www.d2nc.com/

Hook up some motor cables and plug it into your computer and Voila--You have CNC milling capability.

You will also need some other stuff:

A straight through male to male DB25 parallel cable:

http://www.cnc4pc.com/Store/osc/prod...products_id=76

You can use THIS wire for motor cables and home/limit switches. Ground the drain wire ONLY at the driver end.


http://cgi.ebay.com/Servo-Motor-Wire...3286.m20.l1116

You won't need any db9 motor connectors with the G540, as they come WITH it. The G540 also has circuitry for simple spindle speed control and outputs for dc relays to turn coolant pump on or off.

These inexpensive relays are very good :

http://www.surpluscenter.com/item.as...tname=electric

You WILL need 2.7K 1/4 watt current limiting resistors, one for each motor. You can get them here:

http://www.digikey.com/

If you don't already HAVE them, these are excellent home switches:


http://cgi.ebay.com/ws/eBayISAPI.dll...%3D4%26ps%3D42

They are NO, so only for home switches. Limit switches need to be NC. the whole set of 6 switches costs less than ONE switch would cost at Radio Shack.

These limits from Enco will do fine and only cost $2.34 each. Now you know what a deal the home switches are.

http://www.use-enco.com/CGI/INSRIT?P...PMPXNO=7908441

You will also need an estop switch. This one from Keling only costs 10 bucks and works fine:

http://kelinginc.net/CNCPackage.html

CR.

[arondeau]

Guys,
I also am getting set up with a Taig. So what you guys are recommending is to buy a CNC ready, and set it up myself with "better" steppers, etc? As in the components list above?

I have been looking at all options. And from what I see, I cannot go wrong with the Taig. I just want to spend the money up-front and buy exactly what I need rather than waste money upgrading down the road. I am looking at a possible job loss in 2009, and am trying to set something up in my basement to supplement my income, or hopefully make a living!

Andy

[jalessi]

We have experienced problems with the smaller power supply when combined with four steppers.

We prefer the KL23H284-35-4B 387 oz-in steppers on all four axis since they match the G540 drive amperage output.

Using two or three different models of stepper motors is inefficient when you need a replacement or stock backup inventory.

Spending a additional $100.00 dollars for the larger power supply and higher output steppers is cheap when you look at the overall cost of the complete setup.

Jeff...

[Crevice Reamer]

We have experienced problems with the smaller power supply when combined with four steppers.

We prefer the KL23H284-35-4B 387 oz-in steppers on all four axis since they match the G540 drive output perfectly.

Using two or three different models of stepper motors is inefficient when you need a replacement or stock backup inventory.

Spending a additional $100.00 dollars for the larger power supply and higher output steppers is cheap when you look at the overall cost of the complete setup.

Jeff...

So far, no one has found steppers that match the G540 perfectly. That would be a 3.5A 50V best Voltage motor.

Steppers are rated by HOLDING TORQUE. This is never higher than when the motors are standing still, and reduces as speed increases. Higher output steppers are those that will run the fastest with the most power remaining. This is accomplished by powering the motors with their best voltage.

The Taig leadscrews require the motor to spin 4000 revolutions (At FULL step without micro stepping) to move the table one inch. Add Micro Stepping and the revs needed go higher. You will want all the speed possible.

With the G540, any stepper motor with best voltage (32 times the square root of Bipolar Parallel inductance) of more than 50 Volts will run more slowly than a 50V motor. Higher best Voltage above 50V equals lower RPMs with G540. So using a larger motor than actually needed is counter productive.

The 387s come fairly close at 3.5A and 65V though. The 270s are even closer at 2.8A and 60 volts. The 185s are very close at 3A and 49V. These will carry power to higher RPMs, and coupled with the 20TPI gearing should be more than enough for Taig X/Y axes. You WILL need a larger motor for the Z Axis, because this motor has to lift the weight of the head. Hence my recommendation for the 270 oz. motor for Z.

I would not recommend running the 7.3A PSU with 4 3.5A motors, but it should run four 3 and 2.8A motors just fine.

Anyway, the 387s (which are more suited to pushing a big X3 table around) are currently out of stock and thus unavailable.

CR.

[Mark Scrivener]

Thanks Guys. Looks like I was correct - roll your own is the better deal.

And thanks to CR for all the handy links!

[jalessi]

Having the extra torque may be a benefit, the 3.5 amps available from the G540 is used most effectively with the motor choice we use.

I should not have mentioned a perfect match, I stand corrected.

Jeff...

[jalessi]

By the way, the reason why the KL23H284-35-4B 387 is out of stock is because everyone is purchasing them to go along with the G540.

Keling cant keep up with the demand.

Jeff...

[awerby]

[QUOTE=Crevice Reamer;557213] wrote:

The Taig leadscrews require the motor to spin 4000 revolutions (At FULL step without micro stepping) to move the table one inch. Add Micro Stepping and the revs needed go higher. You will want all the speed possible.

[The Taig screws are 20 pitch; that means that 20 revolutions of the motor move the table one inch, not 4000. Microstepping doesn't affect this; it just smooths out the motion somewhat. Yes, you do want to maximize speed, but stepper motors have best torque at lower speeds, so there's a tradeoff here. If you're talking about steps, not revolutions, then you're right - the motors typically have 200 steps per revolution, which multiplied by 20 (pitch) gives 4000. Microstepping multiplies this again by the microstepping factor; a Gecko drive gives you 10 microsteps per step, which comes to 40,000 per revolution.]

Andrew Werby
www.computersculpture.com

[Crevice Reamer]

The Taig screws are 20 pitch; that means that 20 revolutions of the motor move the table one inch, not 4000. Microstepping doesn't affect this; it just smooths out the motion somewhat. Yes, you do want to maximize speed, but stepper motors have best torque at lower speeds, so there's a tradeoff here. If you're talking about steps, not revolutions, then you're right - the motors typically have 200 steps per revolution, which multiplied by 20 (pitch) gives 4000. Microstepping multiplies this again by the microstepping factor; a Gecko drive gives you 10 microsteps per step, which comes to 40,000 per revolution.

Andrew Werby
www.computersculpture.com

WHOOPS! Yes, you are right! I was thinking steps and wrote revs.

CR.

[joeybagadonuts]

Purchasing a G540 right now may not be good advice.

There are several current posts mentioning problems or teething pains with the G540 right now.

Maybe Mark should wait to make a G540 purchase and consider the G201.

JoeyB

[Mariss Freimanis]

Concider? Apple juice for convicts?

My buddy Joey turned me onto this thread.:-) If you use Mach3 and have a 45kHz kernel speed, the motors will top out at 1,350 RPM which is Mach3's limit at 45kHz. Maximum IPM equals RPM divided by TPI so you will get 67.5 IPM.

Torque shouldn't be much of an issue; a 250 in-oz motor is the same as 10 lbs of force on a manual machine's crank handle (I'm guessing a 3" diameter hand-crank).

Mariss

[Garland]

subscribed

[awetmore]

Please use the "Subscribe to this Thread" tool in the "Thread Tools" menu rather than waking up almost 2 year old threads and adding no content to them.

[Mark Scrivener]

Wow - since this thread was resurrected from the dead, I'll provide an update and some pics.

I purchased the Taig CNC ready mill near the end of 2009 (lack of income for most of 2009 delayed my plans). I purchased a G540 based controller and steppers from Jeff Birt (Soigeneris is his company). I also purchased a Sherline CNC ready rotary table for my 4th axis. Software is Alibre (CAD), CamBam+ (CAM), and Mach3 (Control).

I've had the mill a little over 10 months now and continue to be amazed what can be done with this machine. I've cut steel (mainly CRS), aluminum (even 7075 T6), brass (both 260 (yuck!) and 360), gerolite (G10), Delrin, wood, HDPE, acrylic, and prob a few other materials with no problem. Complex shapes that would be impossible by hand are trivial with the CNC. All my fears about not having the flexibility of a manual mill have been put to rest. Anything I could do on a manual machine I can do on my CNC machine faster and more accurate. And that's not to mention all the things I couldn't do without CNC (like the 60 degree wall taper I made on a cut (using a regular EM) by stepping the cut 0.003" each pass).

My workshop:

[TMaster]

Hey Mark! Long time no see! Any Heli flying lately? Trains? Nice taig mill setup! Your motors look a little small though I actually have 2 taig mills now, one with the G540 and the other xylotex. I run the G540 at 35ipm rapids and the xylotex at 25ipm rapids. Good to see you have an enclosure. That makes all the difference. I also have home/limit switches on them.

Great little machines, I extended the Z axis 2" more and the Y axis to 7.5". It took away some rigidity, but it was worth it. Had to replace the gibs with longer ones. The other machine is extended to 6.5 on the Y only. Been running the first one for about 4 years now and have cut an estimated 15 to $20K worth of parts on it. I had to replace the spindle motor last year, all the lead screws and lead screw nuts. Also had to repack the lead screw bearings. The stepper motors are still going strong and everything else. I use mobile 2 vactra way oil. All in all You will get your moneys worth out of this machine. They are the workhorse of the garage shop machinist!

[kanton]

TMaster,

How did you extend the Z axis 2" more and the Y axis to 7.5"? Have you used any kind of column support such as the one pictured below?