Power head for my G0704 - not CNC

[wallyw]

Just took delivery on a G0704. No intention of CNCing this machine. Can anyone recommend a motor setup to give me at least a rapid advance. A slow down feed for boring and threading would be a plus.

Wally

 

[SEK_22Hornet]

I think that you will like your G0704 - however, I suggest that you order a couple spare gears #209 in the parts list). They are $10 each and sooner or later I'll bet you strip one. The first one I stripped is when something I had in the vise was not as secure as i thought and flipped up into the cutter. It took 8 months to get the replacement gear. Last I knew, they had some in stock - I just got 2 more spares. I am in the process of making a belt drive for mine right now to eliminate that and get a little higher RPM out of the mill. I'll post some photos of what I'm doing shortly. As to power cross feed - I believe they sell one for this mil, if i remember correctly (haven't looked for a while). I have an old DC Satellite positioner or two from the big 10' dishes that I'm thinking about using to build a power cross feed some day, and a VonWeiss DC gear motor that I thought might work for the Z axis lift motor. I need to get a couple DC motor drives from ebay to play with on these motors

 

[SEK_22Hornet]

I was looking at All Electronics web site and noticed a couple of motors that might be interesting to try for power feeds. The have right and left hand power window motors and a couple right angle gear motors from power seats (right and left). All are under $20 each and new. The power window motors are rated at 3.5 amps while the seat motors are rated 1.8 amps.

http://www.allelectronics.com/make-a-store/category/400/Motors/1.html

Dan

 

[kizmit99]

So, I'm curious whether anything ever came of this?

I'm starting to think that a power-lift for my G0704 mill head may be a nice project. I'm not interested in going CNC, just something to keep from having to crank the Z-axis handle when raising and lowering the head. The power-window motors that Dan pointed out look like an interesting option...
I'm guessing that they seem like they would operate at about the desired RPM (about the speed I would turn the handle by hand).
I assume, based on their intended use, they must run forward and reverse.
I wonder if they would have enough power though?
And then the big thing, how to actually mount one so it could drive the existing crank shaft?

I did some searching online and couldn't find much of anything dealing with a conversion like this that didn't involved replacing the whole lift assembly and driving the lead screw directly... (of course, maybe my google-foo is just off)...

Anyone have any suggestions?

 

[wrmiller]

I too have no desire to CNC, but would like some assist with the z-axis.

I am thinking of putting a stepper motor on the z-axis and control it with a stepper motor pulse generator that I either build or buy (check ebay). I want to be able to disengage the stepper motor so I can do fine positional movements manually, then reengage the stepper (probably with a lever assy of some sort) for large movements like tool changes.

If I get really ambitious, I'm thinking of converting the z-axis to a 3/4" or 1" ballscrew to get rid of the excess backlash. I'm thinking the larger screw will reduce/prevent flex in the screw as it's floating on one end?

Or I may just counterweight the head with 50lbs or so of iron and stay with the manual handwheel.

Bill

 

[mattthemuppet2]

a power window motor (or cordless drill) should be more than powerful enough. The window motor would be especially useful as most already have the 90deg power take off as standard, so theoretically all you'd need to do is made a splined or hex hole in the output cog and slip that over the head crank handle shaft. I'm waving my hands around as I've never seen your mill in person Then a 12V off an old computer power supply or even a laptop charger brick if it has a high enough output, a double pole switch from radioshack and you're in business. If you can get the crank shaft to go through the motor cog, you could even reattach the hand crank and use that for when you want to go old school.

 

[John Hasler]

I too have no desire to CNC, but would like some assist with the z-axis.

I am thinking of putting a stepper motor on the z-axis and control it with a stepper motor pulse generator that I either build or buy (check ebay). I want to be able to disengage the stepper motor so I can do fine positional movements manually, then reengage the stepper (probably with a lever assy of some sort) for large movements like tool changes.

If I get really ambitious, I'm thinking of converting the z-axis to a 3/4" or 1" ballscrew to get rid of the excess backlash. I'm thinking the larger screw will reduce/prevent flex in the screw as it's floating on one end?

Or I may just counterweight the head with 50lbs or so of iron and stay with the manual handwheel.

Bill

My Avey is counterweighted. Works fine and can reduce backlash. It has a clever adjustment mechanism that allows me to change the balance without changing weights.

 

[outsider347]

My Avey is counterweighted. Works fine and can reduce backlash. It has a clever adjustment mechanism that allows me to change the balance without changing weights.

pictures would be great!

 

[wrmiller]

My Avey is counterweighted. Works fine and can reduce backlash. It has a clever adjustment mechanism that allows me to change the balance without changing weights.

Are you moving the fulcrum/pivot point to change the balance?

I too would be interested in seeing this.

Bill

 

[John Hasler]

Avey counterweight photos:



The star wheel on the diagonal part connecting the two chains moves the connection point of the upper chain, altering the balance.