we have a torchmate 3 4x8 with the hypertherm 1650, it does a decent job for us but sometimes its a little rough, just wanted some other peoples opinions on what they feel would be a better motor, stepper or servo? i know torchmate says steppers, but then why do they offer a servo optional package for more money? if a servo is worth the money i will definetly have my machine retrofitted for them.

The relative merits and demerits of steppers versus servos have been dealt with in rather excruciating detail in a number of prior posts - both Maris and I contributed a lot of info on the subject - over the past year. I used to have a "cheat sheet" with the links but it got lost.

Do a "NC Cams" along with a "stepper" or "servo" term search with the search engine and you should be able to resurrect the threads. The explanations and reasoning has not changed.

When it comes down to the basics there are two advantages of the servo motors over the stepper motors. Speed, and Encoder counts. Please notice that I did not say accuracy because the each motor is as accurate as the other, just that with the encoder counts on the servo motors they will know if they are out of position from where they should be and will attempt to adjust themselves to maintain their position. If they get too far out of position, they will signal the computer to stop the program due to that loss.

The second advantage is speed. Particularly just in the rapid travel speeds moving across the table, the servo's are capable of more then 2000 i/pm where as the steppers are limited to 300 i/pm. Over an extra large table this may have a greater effect then on a smaller table.

You should be well aware of the price of the servo system as well, that will likely be your deciding factor in determining if it's worth the money or not.

I used to have a "cheat sheet" with the links but it got lost.

http://www.cnczone.com/forums/showthread.php?t=17419