Hi everybody. I'm currently in the process of converting a SIEG Super x3 milling machine using the deluxe kit from CNC fusion (http://www.cncfusion.com/smallmill1.html). Anyway I'm asked my electronics supplier to specify a suitable kit to complete the conversion (see below). Being a bit new to this I thought I'd get s second opinion on whether you think the specification is suitable. Any advice would be much appreciated. Thanks, Will

2 x Hybrid Nema 23 Stepper Motors for X and Y Axis.
http://www.motioncontrolproducts.com/c2/uploads/fl60sth86.pdf

FL60STH86-3008BF
Step Angle 1.8 Deg
Step Angle Accuracy 5% (full step, no load)
Resistance Accuracy 10%
Inductance Accuracy 20%
Temperature Rise 80OCMax.(rated current,2 phase on)
Ambient Temperature -20OC~+50OC
Insulation Resistance 100M Min. ,500VDC
Dielectric Strength 500VAC for one minute
Shaft Radial Play 0.02Max. (450 g-load) Shaft
Axial Play 0.08Max. (450 g-load) Max.
radial force 75N (20mm from the flange)
Max. axial force 15N

Voltage = 5.46
Current (phase) = 2.1 A
Inductance (phase) = 12.8 mH
Holding torque = 3 Nm




Hybrid Nema 34 Stepper Motors for Z Axis.

FL86STH80-4280A
Step Angle 1.8 Deg
Step Angle Accuracy 5% (full step, no load)
Resistance Accuracy 10%
Inductance Accuracy 20%
Temperature Rise 80OCMax.(rated current,2 phase on)
Ambient Temperature -20OC~+50OC
Insulation Resistance 100M Min. ,500VDC
Dielectric Strength 500VAC for one minute
Shaft Radial Play 0.02Max. (450 g-load) Shaft
Axial Play 0.08Max. (450 g-load) Max.
radial force 220N (20mm from the flange)
Max. axial force 60N



Voltage = 3.18
Current (phase) = 4.24 A
Inductance (phase) = 3.4 mH
Holding torque = 4.51 Nm
Leads = 8
Length = 80mm

Power Supply
2 x PS 407 - 45V DC at 0A & 42V DC at 7A


3 x MSD542 Microstepping Driver (4.2A Peak)
suitable for driving 2-phase step motors (maximum current ratings of 4.2). Uses an advanced bipolar constant-current chopping technique, and a maximum input voltage of 50 VDC.

Hi,
I'm not a stepper motor fan, but have had lots of experiance with them. I assume a SIEG Super x3 milling machine is some kind of mini mill. I don't know your plans of what you are going to do with this mill, but keep in mind 1) stepper motors are slow 2) stepper motors have no encoder feedback 3) for surfacing, steppers slow down when changing direction, so there will be tool bit deflection marks. ok, with that said, as little differance as there is in price, why not go with the largest motors that will fit? When you are done cutting a prodject, and you are out of posistion, because a small motor stalled, you will be pissed! If someone gives you a job drilling, say, 4 holes in 10,000 parts, you will be mad you don't have servos, that would probably cut machining time in half due to the quick accel/decell & rapid traverse. All the micro stepping stuff means nothing as most any stepper motor will be way accurate enough for any mill. Speed, and power are what you want. If its a mini mill, and it is capable of a 1/2" endmill, and Nema 34 motors will fit on all three axis, go with it. By the way, i have retrofit somewhere around 500 mills with cnc, but series 1 Bridgeport was the smallest. If the SIEG Super x3 milling machine is the size of a series 1 bridgeport, nema 34 with 10-15 turns per inch is borderline small, nema 42 should be used. Good Luck, Buck, Spring Lake cnc llc.