HI everyone. This is my first post.
I have been following the posts for awhile now and have decided to build my own table. So far my plans are going well except for the electrical side. Is there anyone who can set me straight as to where to look for the information that I will need to figure out what size steppers or servos i require for this project.
I would like to consider two servos or steppers to drive the gantry as it will be six feet wide and i would like to use rack and pinion to drive the set up on both sides. I am lost as to weather i need gear reduction or direct drive. I would like to be able to work this out but electrical is not my specialty. Thanks

Let me save you some time. Most of the midrange tables use 400 to 600 oz-in steppers geared down 3:1. You want your target IPM to be 300 to 400 ipm. Since pinions give you step up rations (example a 1.0" DP pnion move 3.1416 in per rev) and Given that most steppers with the proper drive and voltage will do 800 to 1000 RPM with rack and pinion (normally a set up in gearing) a 1" pinion would move 2400 IPM...impressive but not practical. If you trade some of that unusable speed for torque then we are back down to good speeds but with 3X the torque. Why is torque good? Because, when cutting and making rapid quick sharp turns the better your acceleration (from torque) the sharper the corner you can turn.

Servos can actually be smaller since you can gear them 6:1 or higher for the same speeds.

A dual drive axis is easy to do and quite reliable and it doubles the power you have to move the gantry. I have been running a dual drive gantry table for over 3 years. MACH has axis slaving and by using separate home switches for the slaved axis it will auto square the gantry every time you reference to the homes. You can get perfect square on the gantry in relation to axis of the gantry simply by moving one home switch slightly!

Tom
Thanks for the information. this is a good start for me to get going on this project. I have estimated the gantry weight to be 190 lbs and six feet wide. I have two 400 oz/in motors being checked out that I would like to use for x axis. Do you think these will be enough as there will be two of them to move the gantry?

Gary

If you belt reduce them it will be plenty and you will have the added torque for better acceleration. Given a choice of speed or acceleration pick the latter.