Posted: Mon Feb 18, 2013 9:25 pm
Harry, you don't seem to have understood what I am saying but you have come, I think, to the right conclusion - it is holding torque that you should be looking for NOT NEMA size.
Please note that the holding torque is a function of power - and power is the product of voltage AND current - so you can have thicker copper (higher current) or better insulation (higher voltage) - IN ANY Nema size within obvious limitations.
The manufacturers do NOT price on NEMA size (although obviously there is more metal and that costs) but on, predominantly, holding torque. Bigger NEMA is NOT necessarily better, particularly if you have a compact installation, it is just a standard size to allow easy interchange independent of manufacture.
You should be looking for the highest holding torque you can afford - as I said, most CNC experts recommend around 200 Oz-in for your size machine (which, being steel, will be heavier than mine and thus harder to move).
But it's all experimental - I found cheap 35 OzIn steppers and they work well enough for cutting acrylic and wood - but VERY slowly compared to most others.
Please note that the holding torque is a function of power - and power is the product of voltage AND current - so you can have thicker copper (higher current) or better insulation (higher voltage) - IN ANY Nema size within obvious limitations.
The manufacturers do NOT price on NEMA size (although obviously there is more metal and that costs) but on, predominantly, holding torque. Bigger NEMA is NOT necessarily better, particularly if you have a compact installation, it is just a standard size to allow easy interchange independent of manufacture.
You should be looking for the highest holding torque you can afford - as I said, most CNC experts recommend around 200 Oz-in for your size machine (which, being steel, will be heavier than mine and thus harder to move).
But it's all experimental - I found cheap 35 OzIn steppers and they work well enough for cutting acrylic and wood - but VERY slowly compared to most others.