[How do I?] Mini Mill Power Feed

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chip maker

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Hi All,
Am in the process of building a power feed for my Grizzly G8689 mini mill. Got it almost done but as always thinking as I build and have a few questions that I need some help with if possible.
First off I was thinking that maybe I should be installing a fuse to the motor to protect the electronics if there is a motor stall. If I were to add a fuse would I put it in the main motor power feed wire? Also if I do I was going to go with a 5 Amp fuse as that is what they have in the motor on the mill motor. The motor is a 12 volt seat motor.
Next off after getting this together I'm thinking it would be nice to have a jog switch installed as well. Has anyone done this and if you did how did it get wired into the motor feed? Not sure how to wire this up because the power feed has forward and reverse switch. Don't know if this would have to be bypassed to wire up the jog switch.
Thanks John
 
Chip Maker said:
Hi All,
Am in the process of building a power feed for my Grizzly G8689 mini mill. Got it almost done but as always thinking as I build and have a few questions that I need some help with if possible.
First off I was thinking that maybe I should be installing a fuse to the motor to protect the electronics if there is a motor stall. If I were to add a fuse would I put it in the main motor power feed wire? Also if I do I was going to go with a 5 Amp fuse as that is what they have in the motor on the mill motor. The motor is a 12 volt seat motor.
Next off after getting this together I'm thinking it would be nice to have a jog switch installed as well. Has anyone done this and if you did how did it get wired into the motor feed? Not sure how to wire this up because the power feed has forward and reverse switch. Don't know if this would have to be bypassed to wire up the jog switch.
Thanks John
Click to expand...

Looks like it has been a few days with no responses. Im not an expert but I will do the best I can.

For the fuse, I have always seen them between the AC outlet and the live AC input of the power supply. I have occasionally seen one between power supply and motor control board but never between motor control and motor.

For sizing, it will depend on what current the motor and control board are designed to handle. If its designed to take a max of 2 amps and the fuse blows at 5, its already too late and the board can be damaged. However, low voltage motors often have very high current draws and you may find that a 5 amp fuse blows with the motor under very little load.

For a jog function, you will need some kind of speed control. That will be useful for more than just jogging, though you may find the motor doesnt go fast enough for jogging. If you have the same 16 TPI lead screw my machine had and the same 190 RPM motors I am seeing on google, you will have a max speed of 12 IPM.

On my power feed, I used a stepper motor and arduino to turn at about 1000 RPM and jog at 60 IPM and that speed seemed manageable.

Does that help at all? Let me know specifics about your motor and I can try giving a better answer.
 
shooter123456, Thanks for the reply I just got home from work but will get a bit more info tomorrow for you to see what I have. I can also have a few photos as well.
 
Shepherd said:
Shooter, do you have any schematics or pics of your set up?
Click to expand...
I have some pictures of it on this thread here: http://www.hobby-machinist.com/threads/x2-power-feed-build.51350/#post-435432

I cant get any more because that machine is CNCd now. No schematic but the wiring was very simple. AC L, N, G to DC power supply. DC power supply to stepper driver DC input. Stepper to driver output. 2 Arduino output pins to step and direction input on driver and step and direction - on driver to arduino ground.

Thats all you need for most of it. Then you just need to decide how you want to control it. With an arduino, a simple control panel is an option. You can have 4 buttons and a potentiometer for speed and direction. 2 buttons for "move while held down" and 2 for "move when pushed, stop when pushed again" and the pot can control speed.
 
The motor driver has overcurrent protection. You should not need fuses between the motor and driver.

Sent from my SM-G950U using Tapatalk
 
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