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Power head for my G0704 - not CNC
- Thread starter wallyw
- Start date
- Joined
- Jun 26, 2013
- Messages
- 191
I did a little more playing with the power window motor this evening...
It seems to have plenty of power for using it as a x-axis drive. Still a little slower than I would be happy with at 12v. If you crank the voltage up, the RPMs increase as well, and at 20v it moved the table at a reasonable clip. No clue how long it would last being used that way though. Since it doesn't seem to be struggling I suspect it could be run at 12v and geared up and still have plenty of torque to operate on that axis.
I then decided to give it another shot at the z-axis handle. Pushing the drive voltage to 16v and the current to about 6 amps, the motor actually does have enough torque to both raise and lower the head, but just barely. Also, the motor heats up pretty quickly, not terribly hot, but hot enough that I wouldn't trust it to last very long. And even over driving it like that, the speed isn't quite acceptable.
I've got a 1/2HP old garage door opening that I'm certain would be plenty powerful enough. I've seen where at least one guy managed to hook one up to drive his z-axis and it seemed very successful. His mill was larger than the G0704 though and had a reasonable place on top of the column to mount it. I suspect it would be very out-of-place on the top of this mill's column...
I'm considering trying a wiper motor if I can source one cheaply enough (read: free). I've read that some don't like running in reverse, so that could be a concern with that approach...
It seems to have plenty of power for using it as a x-axis drive. Still a little slower than I would be happy with at 12v. If you crank the voltage up, the RPMs increase as well, and at 20v it moved the table at a reasonable clip. No clue how long it would last being used that way though. Since it doesn't seem to be struggling I suspect it could be run at 12v and geared up and still have plenty of torque to operate on that axis.
I then decided to give it another shot at the z-axis handle. Pushing the drive voltage to 16v and the current to about 6 amps, the motor actually does have enough torque to both raise and lower the head, but just barely. Also, the motor heats up pretty quickly, not terribly hot, but hot enough that I wouldn't trust it to last very long. And even over driving it like that, the speed isn't quite acceptable.
I've got a 1/2HP old garage door opening that I'm certain would be plenty powerful enough. I've seen where at least one guy managed to hook one up to drive his z-axis and it seemed very successful. His mill was larger than the G0704 though and had a reasonable place on top of the column to mount it. I suspect it would be very out-of-place on the top of this mill's column...
I'm considering trying a wiper motor if I can source one cheaply enough (read: free). I've read that some don't like running in reverse, so that could be a concern with that approach...
- Joined
- Sep 3, 2012
- Messages
- 311
How about a wiper motor off of a lite truck?
- Joined
- Jun 26, 2013
- Messages
- 191
From some of the research I've done it seems that wiper motors are pretty much built to run in one direction only. They may run in reverse, but apparently they use a special brush configuration that may make them less efficient and cause them to wear out quickly. If I tripped over one, I would give it a try though.
I'm beginning to think that this may be one of those projects where just buying the right parts up front would be the cheapest solution. Hoss (of g0704.com fame) has shown that a 570 oz/in stepper is powerful enough to drive the factory z-axis screw, and those can be had for $50. If that was it, I would just go with that - but you also need a stepper controller. From what I can tell, that costs about another $100. Even then I'm not sure that doesn't also require something to be the "brains" to control.
I'm gonna give the motors I've got a try at driving the lead screw from above (instead of from the handle) and see if that doesn't increase efficiency enough to make them practical...
I'm beginning to think that this may be one of those projects where just buying the right parts up front would be the cheapest solution. Hoss (of g0704.com fame) has shown that a 570 oz/in stepper is powerful enough to drive the factory z-axis screw, and those can be had for $50. If that was it, I would just go with that - but you also need a stepper controller. From what I can tell, that costs about another $100. Even then I'm not sure that doesn't also require something to be the "brains" to control.
I'm gonna give the motors I've got a try at driving the lead screw from above (instead of from the handle) and see if that doesn't increase efficiency enough to make them practical...