The New Machine

[Ricardoco]

No you don't get more torque, stepper motor produce most torque when stalled, as you increase the rpm the torque drops.

I know well know manufactures of encoder scale that produce an 8um pitch and you have all the american stuff.

When i built my first cnc'd x1 i was using a imperial z screw, you never need to know the interger apart from the time you enter it into the control software.

By using pulleys you get
-another source of backlash
-drive flex(belt stretch)
-reduced top speed
-side load on the screw
+ratio change
+allignment flexabilty

i tried belts on a lathe, big disapointment. now directly driven.

if we are quoting "you can lead a horse to water but cannot make it drink" I personally think your logic is flawed, if you want an additonal challenge that is far enough.

As for i am old school i like to watch it, the x1 had a rapid of 400mm/min and it got very old very quickly and that was a smaller machine.

I actually felt like you were telling me off then....

Well i will consider myself told shall I....:cry:

Usually people dont have to be so blunt to get the point across, Im not so stuck in my ways that im not open to suggestion, On a recent project I took a lot of advice from the members of this forum and put it into practice, that is why i participate in forums.

I dont really want to just copy you or hoss, but neither do i want to re-invent the wheel.

thats why i dont just guess at this, I've looked at several sources of information and am still looking, here is just one source.

http://www.arrickrobotics.com/pr23.html

I dont disagree with all you say, and there are sacrifices to be made using pulleys however my 260 is not direct drive, it is very accurate, as much as i need anyhow, and i really dont want the steppers hanging of the end of the axis (not sure what you would call a group of axis lol), so do you have any other suggestions?

Thanks in advance for your input.

[Jonathan]

I forgot to mention the other big advantage of belts which is that they greatly reduce resonance problems.

The site you linked to has mentioned what I did:

'Even though the output speed is reduced by the reduction ratio, some systems will actually have their overall speed performance increased due to better use of the motor's torque curve.'

I wouldn't hesitate to use belts again - I will when I convert my lathe, though admittedly that's partly because it'll have a rotating ballnut.