Which one? 1160oz-in or 632oz-in?

[The Blight]

Like the topic says. Which one should I go with? (I will order 3 to use on all axis of a X2 mill). I know the 1160 will be a bit of an overkill and I will be using direct coupling to the ballscrew which has a 2mm pitch, so I'm not going for speed. What I want is for it to be reliable and never to miss a step. I might also use the steppers on some bigger machines later on, but I'm not sure. Might go with servos instead then. So do you think I should buy the 632 or the 1160 steppers? I can afford any of them, so money is not an issue when it comes to these two types. I will also be using G202s.

[nine 16]

The Blight,

Great question. It was on my mind just yesterday when looking at my own (as-yet-un-cnc'd) x2.

Is it possible that a motor larger than necessary to achieve the performance desired may begin to be a detriment due to the greater inertia of its own components relative to the mass of the mill parts?

[dertsap]

Like the topic says. Which one should I go with?

you may want to sit down and figure that one out yourself ,or possibly rephraze your question

[S_J_H]

massive overkill IMO for either choice. I use 269oz steppers on my x2 and if the machine is adjusted properly I never miss a step.
Hey you have to realize the little x2 just can't rip and roar through metals.
A 269oz stepper has more than enough power for this mill.
Steve

[BobWarfield]

massive overkill IMO for either choice. I use 269oz steppers on my x2 and if the machine is adjusted properly I never miss a step.
Hey you have to realize the little x2 just can't rip and roar through metals.
A 269oz stepper has more than enough power for this mill.
Steve

I agree. I would go with the 600 oz in at most.

Best,

BW

[patndel]

Hi Blight,

The guys here are very right, the 1160oz and 600oz steppers are way overkill for the X2. As you move up in motor frame size (nema 23 > nema 34), there is a distinct drop in high speed performance. I realise you state speed is not an issue, but seriously on these little machines, the key is quick shallow cuts, they are simply not rigid enough to hog through metal.

The other thing to consider is the cantilevered weight of a nema 34 motor hanging off the end of the axis, allowing for your bearing housing and coupler, you'll be pushing the weight of the motor another 2 or so inches past the end of the table, adding unnecessary load on the dovetails.

I'm running nema 23 (450oz) motors on my X3, X and Y directly coupled, with the Z axis belt driven 2:1, running 0.02" pitch ball screws and nuts.

I'd suggest sizing the steppers to the mill, 269oz for the X and Y, and a 450 or 500oz nema 23 motor for the Z. You can get away with a xylotex controller with these motors, and save the big bucks for your larger machine if you out grow the X2.

Pat

[philbur]

Looks like the consensus is that 1200 is way over kill so the answer is 640, especially if you really intend on using a 2mm pitch. It’ll twist the hind leg of a donkey. The fact that you may use them on a large machine later is irrelevant to this discussion if you do not say how much larger and the probability of them being used.

The Tormach PCNC1100 is an 1100lb machine with 5mm pitch (direct drive) and has 640 on the x and y and 1200 on the z. It never misses a beat, unless you crash it.

Regards
Phil

Like the topic says. Which one should I go with? (I will order 3 to use on all axis of a X2 mill). I know the 1160 will be a bit of an overkill and I will be using direct coupling to the ballscrew which has a 2mm pitch, so I'm not going for speed. What I want is for it to be reliable and never to miss a step. I might also use the steppers on some bigger machines later on, but I'm not sure. Might go with servos instead then. So do you think I should buy the 632 or the 1160 steppers? I can afford any of them, so money is not an issue when it comes to these two types. I will also be using G202s.

[philbur]

0.02" pitch? Thats 50tpi, are you sure, or do you mean 0.2"

Regards
Phil

I'm running nema 23 (450oz) motors on my X3, X and Y directly coupled, with the Z axis belt driven 2:1, running 0.02" pitch ball screws and nuts.

Pat

[The Blight]

I know what metals thic machine can cut and how much it can take and I do work with mills and lathes every day (both CNC and manual).

How big a machine I will be working with in the future? As big as it can get. How likely? That I don't know yet. And I probably wont know until I find a good offer. You can't really plan this until you have a good workshop and the money.

600 it is then. 4kg is a bit much and that was what made me ask this question.

I guess my problem is that when I'm going to spend a lot of money on something, I tend to buy something that is way overkill just to be on the safe side. And in this case it only cost a little extra.

Maybe I will just step it down to 400 and save the money for other projects.

[Runner4404spd]

step down to the smaller steppers, when you go to a larger machine you want servos anyway.

[The Blight]

Thats what I thought. And I have now found some new steppers (500 oz-in NEMA23 frame) and a new drive board (hobbycnc board) which saves me a lot of $. I think this will be good enough.

Thanks for your help guys! Now all I have to do is change the drawings of the mounting plates.

[patndel]

0.02" pitch? Thats 50tpi, are you sure, or do you mean 0.2"

Regards
Phil

Yup ... my mistake, they are actually 0.2" pitch ball screws (5 tpi)

Pat