I am looking at a PM940 (the one I have ordered doesn't even have an ETA yet) and one of the features I am wanting is the PDF which I assume is done with gears in the head unit. Pretty strong transfer of power I would think. I was wondering if you had a DC gear motor hooked up to a speed controller could you lock the spindle in the up position and feed the head down for drilling and using a boring head with the speed control turned way down? In other words what the PDF feature is used for. I have a new/old stock Leeson 90V 2 amp 1/4 hp 100 inch lb 125 rpm gear motor. Also have a new/old stock Dart speed controller with forward/brake/ reverse. With the shaft clamped in a vise grip you cannot stop it when it first starts to move with the speed turned down to lowest setting. I have heard the 90v DC motors have similar torque through out the speed settings as they are used to run conveyors and need the same power at whatever speed they are set at.
I was wondering if that would be too much pressure on the lead screw and nut assembly? I am thinking you do the same thing on the X axis but I know some times the downward pressure when drilling,say a 1" hole in steel, can be much greater. If it was a CNC ball screw it would probably handle it much better.
I was watching Pragmatic Lee on you tube and he has a Z feed coming in from the crank handle that turns at 67 rpm with no speed controller and he says it is to slow so this 125 rpm with a speed controller would be perfect I am thinking. Also assuming 125 rpm coming in from the crank handle shaft would be in the ball park what rpm would a motor used to turn the lead screw directly from the top have to be. How would I convert that numbers wise? I don't have a mill to look at otherwise I could open it up and use a tachometer on it. I was just wondering as I have a few other 90v DC motors that I could use to mount on top if I knew what rpm would be appropriate. Also how would you couple the motor on the lead screw at the top. I am thinking it can be done as that's where they put their Z axis power feed units.
Looking at a screenshot from Lee it looks like equal size gears so same speed? I could mount it on the top or side?
Now that I think of it boring probably wouldn't be as accurate as using the spindle bearings vs riding on the ways.
Also this from PM Lead Screw Type: Inch Pitch Acme Threads – 10TPI on X and Y Axis. Not Z I am guessing.
I was wondering if that would be too much pressure on the lead screw and nut assembly? I am thinking you do the same thing on the X axis but I know some times the downward pressure when drilling,say a 1" hole in steel, can be much greater. If it was a CNC ball screw it would probably handle it much better.
I was watching Pragmatic Lee on you tube and he has a Z feed coming in from the crank handle that turns at 67 rpm with no speed controller and he says it is to slow so this 125 rpm with a speed controller would be perfect I am thinking. Also assuming 125 rpm coming in from the crank handle shaft would be in the ball park what rpm would a motor used to turn the lead screw directly from the top have to be. How would I convert that numbers wise? I don't have a mill to look at otherwise I could open it up and use a tachometer on it. I was just wondering as I have a few other 90v DC motors that I could use to mount on top if I knew what rpm would be appropriate. Also how would you couple the motor on the lead screw at the top. I am thinking it can be done as that's where they put their Z axis power feed units.
Looking at a screenshot from Lee it looks like equal size gears so same speed? I could mount it on the top or side?
Now that I think of it boring probably wouldn't be as accurate as using the spindle bearings vs riding on the ways.
Also this from PM Lead Screw Type: Inch Pitch Acme Threads – 10TPI on X and Y Axis. Not Z I am guessing.
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