[WarrenW]

Okay, this is definately a newbie question!

I have done alot of research on this site but can't figure one thing out yet. There are alot of different threaded rods available to use which vary is the number of threads, the diameter of the rod, etc. I also know changing this can change the resolution of your work.

Now how do I determine what side to use for moving the gantry on the x axis? And then do I use the same size for the Y and Z axis? So I do a setup with the computer / drivers to know the thread size so it does the work in the right size?

For example, right now I'm building a small cnc router to lean from using the plans from solsylva.com and it calls for 5/16-18 threaded rods. When I bought them from Home Depot there flexed alot. Now if I want to build a bigger machine that used a larger leadscrew for moving the gantry, how would I know which size? Or if I just picked on that was larger and stronger, how do i make it work right with the software?

Its probably very simple and I just have not gotten that far yet...

Thanks!

Warren

[One of Many]

Generally, this will be a parameter setting that will set the distance each pulse is worth or how many pulses X.XXXX would be worth. That number will differ with the pitch and ratio of either a pulley system, or direct drive. The software and/or control should explain this to some degree. The pulses may be equal to a stepper output or encoder feedback, depending on stepper, servo, open or closed loop systems.

It would be simpler to use the same pitch to keep the ratios the same. There by the parameter settings equal also. Finer pitch will move slower with greater force but have higher resolution. Courser pitch will move faster, but have less resolution and cutting force.

It is safe to assume the 18 pitch has proven to work well with the design they use. A larger screw would not change the above parameter if the pitch stays the same, but it will have greater friction and weight, therefore will probably take a larger motor to compensate for those losses.

I'm sure there is a happy medium based on the power the motor can use most efficiently at a speed that compliments the spindle power and structure of the machine.

DC