Mini Mill Tune Up And Power Feed

[bmac2]

Christmas and New years have past so I’m back to tuning/cleaning up my mini mill. I saw in the Princess Auto flyer (the Canadian version of Harbor Freight) they had white lithium grease on sale. Any time I go to Princess Auto I take a wander through the surplus section. Most times it’s like going to the dollar store but I have found some good stuff, brand name tools, heat shrink, zip ties and once Mitsubishi NEMA17 and NEMA24 stepper motors.
I’d seen these worm shaft motors in surplus for a while but with no nut, an unknown voltage and the absence of any other spec I wasn’t interested. But I’d been thinking of adding a power feed on the X axis so I looked up the part number on the internet and low and behold.

P/N: 5503740 D
Power Seat Tilt Motor for a Chevrolet Malibu
RPM: 190 RPM @ 12 Volt DC
1.5A No Load /17A Stall @ 12V.

I figured if it had got enough power to lift my 210lb butt in a car it should work as a power feed and the 190 RPM seems about right so I dropped the $9 Canadian and took one home. Messing around on the bench I couldn’t stall it with my hand at 5V so it’s got some torque and at 12V no way was I going to stop it.

So this is my rough plan. The frame will be 1/4” aluminum where I need rigidity and 3D printed where it just needs to keep the chips out. A few years ago when I first got into casting I was lucky enough to be gifted a lot of aluminum scrap from a local fabrication shop and a lot of it was 1/4” plate so I think I’ll mock up the frame just to get a better feel of how things are going to fit.

The motors are sold as right hand and that would put the motor above the bed. I don’t think I have ever had anything on this little mill sticking out to where this could become an issue but I don’t like the idea. It turns out that you can just undo the 4 screws and swap it around making it left hand and that will put the motor down below the bed.

 

[timo_gross]

Haha, probably would have bought one. On a Mill with 4 mm screw pitch this would go about 760 mm/min. Probably good enough, if you can slow down properly. Worst case it does not work as you hoped.

On my mini Mill the motors stick out to the side. You need to check if anything is in the way when you drive the y-axis full stroke.
Is your mill on a stand? Is vertical down any option? If possible, I would also try to keep everything below table top, just in case you will have a part that is longer than your table. The day you decide to mount something, you will need to drill a hole in the end of a table leg .
I would even try to move the clutch handle to the front, not up.

The next thing I wonder would that be suitable for a quill feed? Or can it raise and lower the head of the mill?

Success and keep posting how it is going.

Greetings Timo

 

[terry123]

Will definitely be following this one! I have pondered something similar but was unsure about how to power a DC motor.

 

[timo_gross]

Will definitely be following this one! I have pondered something similar but was unsure about how to power a DC motor.

To power the DC motor I would use something similar to this one with a microcontroller to do PWM control. (does not have to be that brand, similar devices are available elsewhere)

https://www.pololu.com/product/2991

With those extremely cheap ones. I had mixed results, as they tend to state "magic smoke Amps" instead of the matching motor rating. So we need to be careful with those. I have a smaller version similar to the one on the picture on my míni drill press. It constantly trips when starting the motor with too high throttle. (slowly speedig it up it is fine, it is small and in a metal box, so when it catches fire it will not be an issue )
They tend to state values that are mixed collection from the datasheet. e.g. Absolute max. Amp together with absolute max. Voltage.
So instead of 60Vx20A = 1200 W the thing might be only capable of 9V*5A=45W or 12Vx3A=36W. at 60V it might go up in smoke or at 20A whatever comes first.


o

Greetings Timo

p.s. at our hobby use, it is sometimes even good enough. Degrading over time, but used sparse enough to give sufficient life span. (low price)

 

[bmac2]

Hi Timo. Murphy's law would dictate you are 100% right on something coming up as soon as it’s installed. My Mill sits on the bench and I have around 4 inches of clearance to the bottom of the bed. Good call on the clutch handle, I’ll definitely set it up so it’s in the front. I’ve been playing around with the motor and for a small motor it has a ton of torque so when you say “quill feed” on something like a drill press it could work. My mill is a Craftex CX605 and uses a rack and pinion on the head and I cant visualize how it would work.



Terry. For power . . . Ya. What Timo said

 

[burns]

Hi, here's what I made, similar 12v motor layout. Used micro switches to start/stop and reverse. Also put microswitch x2 on the mill bed to prevent overun/crash. Has a dog clutch so traverse hand wheel can remain in use. Hope pictures are useful.

 

[timo_gross]

Quill feed I had something like this in mind.

Depends of course how the machine looks. And it depends what is necessary to put the motor on.

 

[cheepo45]

I have had a seat motor power feed on my Mill-Drill for years.
It is powered by a battery charger with a light dimmer for speed control.
It works quite well.
Scott

 

[terry123]

I have had a seat motor power feed on my Mill-Drill for years.
It is powered by a battery charger with a light dimmer for speed control.
It works quite well.
Scott

I have been kicking around ideas for a low cost power feed on my mini mill for a year or so. The AC to DC transformer has been the main stumbling block. If I might ask-how many amps does your charger produce and how does it hold up under extended usage?

 

[BaronJ]

Christmas and New years have past so I’m back to tuning/cleaning up my mini mill. I saw in the Princess Auto flyer (the Canadian version of Harbor Freight) they had white lithium grease on sale. Any time I go to Princess Auto I take a wander through the surplus section. Most times it’s like going to the dollar store but I have found some good stuff, brand name tools, heat shrink, zip ties and once Mitsubishi NEMA17 and NEMA24 stepper motors.
I’d seen these worm shaft motors in surplus for a while but with no nut, an unknown voltage and the absence of any other spec I wasn’t interested. But I’d been thinking of adding a power feed on the X axis so I looked up the part number on the internet and low and behold.

P/N: 5503740 D
Power Seat Tilt Motor for a Chevrolet Malibu
RPM: 190 RPM @ 12 Volt DC
1.5A No Load /17A Stall @ 12V.
View attachment 163739

I figured if it had got enough power to lift my 210lb butt in a car it should work as a power feed and the 190 RPM seems about right so I dropped the $9 Canadian and took one home. Messing around on the bench I couldn’t stall it with my hand at 5V so it’s got some torque and at 12V no way was I going to stop it.

So this is my rough plan. The frame will be 1/4” aluminum where I need rigidity and 3D printed where it just needs to keep the chips out. A few years ago when I first got into casting I was lucky enough to be gifted a lot of aluminum scrap from a local fabrication shop and a lot of it was 1/4” plate so I think I’ll mock up the frame just to get a better feel of how things are going to fit.
View attachment 163740

The motors are sold as right hand and that would put the motor above the bed. I don’t think I have ever had anything on this little mill sticking out to where this could become an issue but I don’t like the idea. It turns out that you can just undo the 4 screws and swap it around making it left hand and that will put the motor down below the bed.

View attachment 163741

View attachment 163742

View attachment 163743

Hi Bmac2,

I did a very similar thing using a car window wiper motor. For what its worth you could just reverse the power supply and the motor will run in the other direction.
I tend to run mine at about 6 or 7 volts from a 3 amp variable voltage power supply. At 30 volts it gives me a fast traverse.

I incorporated a tumbler reverse so I can simply change direction by moving a lever. I did this because wiper motors don't like running in reverse. But I think that you will find that your motor won't care either way, since that is what would happen when lowering the seat.

 

[SmithDoor]

Christmas and New years have past so I’m back to tuning/cleaning up my mini mill. I saw in the Princess Auto flyer (the Canadian version of Harbor Freight) they had white lithium grease on sale. Any time I go to Princess Auto I take a wander through the surplus section. Most times it’s like going to the dollar store but I have found some good stuff, brand name tools, heat shrink, zip ties and once Mitsubishi NEMA17 and NEMA24 stepper motors.
I’d seen these worm shaft motors in surplus for a while but with no nut, an unknown voltage and the absence of any other spec I wasn’t interested. But I’d been thinking of adding a power feed on the X axis so I looked up the part number on the internet and low and behold.

P/N: 5503740 D
Power Seat Tilt Motor for a Chevrolet Malibu
RPM: 190 RPM @ 12 Volt DC
1.5A No Load /17A Stall @ 12V.
View attachment 163739

I figured if it had got enough power to lift my 210lb butt in a car it should work as a power feed and the 190 RPM seems about right so I dropped the $9 Canadian and took one home. Messing around on the bench I couldn’t stall it with my hand at 5V so it’s got some torque and at 12V no way was I going to stop it.

So this is my rough plan. The frame will be 1/4” aluminum where I need rigidity and 3D printed where it just needs to keep the chips out. A few years ago when I first got into casting I was lucky enough to be gifted a lot of aluminum scrap from a local fabrication shop and a lot of it was 1/4” plate so I think I’ll mock up the frame just to get a better feel of how things are going to fit.
View attachment 163740

The motors are sold as right hand and that would put the motor above the bed. I don’t think I have ever had anything on this little mill sticking out to where this could become an issue but I don’t like the idea. It turns out that you can just undo the 4 screws and swap it around making it left hand and that will put the motor down below the bed.

View attachment 163741

View attachment 163742

View attachment 163743

The biggest problem I found with building a power feed is a simple easy to build cluch.

I have used electric clutch not cheap but work great.
Did this on a 6,000 pound horizon mill.

A good DC drive and controller is 60 to 1 so will go to as high as 100 to 1. That is great for power feeds and fast speed aka (rapid Traverse).

It just finding good easy cluck today.

Dave