[mosaicdave]

Hi all--

I'm just wondering if anyone is using, or has used, 166 oz-in stepper motors on their Taig mill. I've been looking at the SmoothStepper package from soigeneris.com; he primarily suggests these small motors for the Taig, stating that they're plenty strong enough on account of the Taig's fine-pitch leadscrews, and he has videos of cutting aluminum at high feed rates, etc. I find the theoretical arguments in favor of low inertia and low inductance convincing. And, I like the small size of the 166 oz-in motors, which will stick out off the end of the x- and y-axes a couple or three inches less... But, has anyone found these motors to be underpowered in practice? I'm particularly concerned about raising the z-axis, with it's heavy motor payload, as well as needing force to overcome friction if I decide to tighten down the X and Y gibs to better deal with backlash.

Nearly all of the parts I'm going to be making on this machine will be tiny plastic parts cut with tiny tiny endmills, so I don't think the actual cutting forces involved will present a difficulty for the small motors.

Any advice either way very welcome;

Thanks--

--dave

[jalessi]

Dave,

My decision would be based on looking into the future a bit and thinking about upgrades such as ballscrews or even a larger much heavier machine such as a G0704.
G0704 Drill/Mill with Stand
Most hobbyist outgrow there first machine in a few years.

That being said, I would spend a few extra dollars and purchase something like the KL23H2100 381 ounce motors.
http://www.kelinginc.net/KL23H2100-35-4B.pdf

I am assuming you are going to use a Gecko G540 drive, paired with KL23H2100 is a very good all around match.

Welcome to the Zone,

Jeff...

[Mr. G]

For working on small plastic parts the TAIG will absolutely blow away that G0704. No way the Grizzly will be as smooth or have less backlash. All chinese made machines are kits that take a lot of work to get squared away. besides, you will gain only about 1/2" Y and 6" X travel vs the TAIG. Z is pretty substantial.

Personally, I would not undersize the steppers. You will want quick rapids to get any work done, even if your cutting is going to be done at slower rates. but with plastic you need low spindle rpm with high feedrates to avoid melting.

[jalessi]

Mr. G,

No doubt the Taig is a great entry level micro mill however,

The Taig is in kit form as delivered to Dave and requires assembly,CNC electronics, software, etc... to complete.

The Taig would be a fine machine to just mill small plastic parts.

On the other hand if Dave decided he needs more capacity to do larger metal work the G0704 may be a bit more capable.

The G0704 dwarf's the Taig in size, weight, spindle motor horsepower and end mill size capacity.

With a subtle amount of work (ballscrews and CNC conversion kit) the G0704 will make a very capable machine.

Why not ask Hoss2006 (Daniel) if the "TAIG will absolutely blow away that G0704".

Jeff...

[Mr. G]

Sorry, but I stand by my statement about the TAIG being a better machine out of the box than any chinese mill. Unless Daniel, or whoever has owned both then their opinion on the matter is moot. I have owned an X2, and I currently own the Grizzly 3103. X2 is a pile of crap. The 6x26 (3103) is a nice knee mill, but for aluminum, plastic, the TAIG is better. Especially CNC'd. Obviously where capacity is concerned the TAIG is limited. But as he stated, he is working on a small part level, and plastic. The assembly of the TAIG is trivial, and fitting the steppers is a non-event. Compared to what it will take to get that Grizzly converted, are you kidding me? I could have a TAIG, steppers, G540, and power supply up and running and making parts in about 2 hours.

[jalessi]

Mr. G,

I disagree, I do not believe the Taig is a better machine out of the box.

For the money both machines are built extremely well and perform as designed.

Many vendors including CNC Fusion and BDTools make a easy to install CNC kit for the G0704.
CNC Fusion
bdtools | eBay

I agree that it takes less time to do the CNC assembly on the Taig, two hours is commendable.

Jeff...

[jalessi]

Dave,

I apologize for side tracking your thread.

Jeff...

[Mr. G]

No way. Even on Hoss's own web side he talks about the leadscrews being at best .002 to .005 backlash. Taig is closer to .0005 as delivered. Not to mention the pitch accuracy. Runout on that r8 spindle from china is going to be a thou or two. for holding small tools R8 sucks. the er16 on the taig is far superior at tir as well as grip on the tool.

[jalessi]

Mr. G

There are many vendors that sell R8 ER16 Collet Chucks that will hold .0005 or better runout.

Ballscrews would alleviate the G0704 leadscrew shortcoming.

I am not faulting the Taig, it is a fine machine.

I originally suggested thinking about future projects and maybe a larger machine.

Have a most awesome evening,

Jeff...

[bjones]

Sorry, but I stand by my statement about the TAIG being a better machine out of the box than any chinese mill. Unless Daniel, or whoever has owned both then their opinion on the matter is moot. I have owned an X2, and I currently own the Grizzly 3103. X2 is a pile of crap. The 6x26 (3103) is a nice knee mill, but for aluminum, plastic, the TAIG is better. Especially CNC'd. Obviously where capacity is concerned the TAIG is limited. But as he stated, he is working on a small part level, and plastic. The assembly of the TAIG is trivial, and fitting the steppers is a non-event. Compared to what it will take to get that Grizzly converted, are you kidding me? I could have a TAIG, steppers, G540, and power supply up and running and making parts in about 2 hours.

have you owned a g0704? if not then by your logic your opinion on the matter is moot as well. if you are basing your opinion of all chinese mills on the lowly x2 that is ridiculous, the tormach is a chinese mill too. i do agree that if all you want to make are small plastic parts there is no need to upgrade to a larger much more capable machine, the taig will be fine for you.

[thumper650]

I think I was one of the first to buy a controller g540 and smoothstepper from Jeff at soigeneris.com. Checked my records and it was May31 2009. I cut a 4"x4"x1" piece of UHMW. This is kinda a gummy plastic. I cut .250 depth passes,4 passes and I'm done. I run at 70ipm with a 1 flute cutter made for plastic. All I can say is it looks like wood spitting out of a chain saw. This is with the 166oz steppers. I've never owned a cnc machine before having the smoothstepper so I cant compare to experience. Can say by looking at videos of other setups the stepper noise and slow speed would put me too sleep.
Had one time I forgot to turn the spindle on. The 1/4" cutter contacted the piece i was cutting then pushed the spindle column till it was leaned to the side. These little motors are strong.

[DLA_Dezign]

I think I was one of the first to buy a controller g540 and smoothstepper from Jeff at soigeneris.com. Checked my records and it was May31 2009. I cut a 4"x4"x1" piece of UHMW. This is kinda a gummy plastic. I cut .250 depth passes,4 passes and I'm done. I run at 70ipm with a 1 flute cutter made for plastic. All I can say is it looks like wood spitting out of a chain saw. This is with the 166oz steppers. I've never owned a cnc machine before having the smoothstepper so I cant compare to experience. Can say by looking at videos of other setups the stepper noise and slow speed would put me too sleep.
Had one time I forgot to turn the spindle on. The 1/4" cutter contacted the piece i was cutting then pushed the spindle column till it was leaned to the side. These little motors are strong.

Would love to see video of that, do you have any?

[thumper650]

No I don't. I build a led light stand for the industry i am in. This is a nautilus shaped piece I mill. I do the 2 at a time 100 pieces at a sitting. I have these pieces waterjetted now. He can make them cheaper that i could buy the plastic.

[Jeff-Birt]

There are a LOT of misconceptions when it comes to sizing a stepper motor for a machine. Despite the popular belief, bigger is not always better. The Taig uses 20TPI lead screw. This gives a whole lot of mechanical 'gear' reduction, so you get a boat load or torque and a corresponding reduction in speed. The best choice of a motor is then one that provides a quick acceleration and good maximum velocity. This is the reason for my 'tiny' stepper motors. They are only a double stack motor so they have less mass than the very long 380oz-in NEMA23 motors, and lower inductance. This adds up to really good acceleration and excellent maximum velocity. The result is a Taig that do 100 IPM with ease.

With 20TPI screws on the Taig and x10 microstepping of the G540 you wind up with 40,000steps/inch. To get any speed out of this you need a fast a reliable pulse train. That is where the SmoothStepper comes in, it can output a step pulse train that is far more accurate and far faster than the parallel port can. (The parallel port driver is limited by the underlying hardware and software drive timing.)

[Eldon_Joh]

I run 425 oz steppers at 2.2 amps. IIRC i'm running into the inductance limit with the Gecko drives, as i'm only driving them from 35 volts iirc, so the amp limit is only applicable at lower speeds.
anyhow, what i've found is most of the friction is in the leadscrew nut, and the gibs, but i have my machine run very tight.

if you're cutting plastic with a one flute cutter at 70 IPM you probably don't care if your table has .001" of play side to side across the slides, so 166 oz steppers are probably sufficient.
I run the lead screw nuts and the gibs tight enough that the steppers will stall if I try to run 30 ipm, without cutting anything.

[Jeff-Birt]

I keep my machine adjusted so I have less than 0.001" of backlash and machine everything from plastic to tool steel. My 'tiny' 166oz-in motors have never been the limiting factor. I can still run 100IPM all day long. Big motors simply are not better in this application.

I've posted these video link before but here it goes again:

250 IPM SS - YouTube

[Eldon_Joh]

It takes about 30 ounce inches just to turn the leadscrew on my taig, and that's just the .002 inches of backlash before the table starts to move.