Author Topic: Mini-mill power feed on a tight budget.  (Read 9566 times)

Offline websterz

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Mini-mill power feed on a tight budget.
« on: April 25, 2009, 07:54:39 PM »
For under $50.00...that's within just about everyone's budget. I don't have pics yet but I will lay out the parts list. Tomorrow I will take my camera out with me.

The motor I am using is from a 14.4 volt cordless drill. I got mine on Ebay, minus the battery and charger, for $9.99...shipping was free. If you have a flea market or Salvation Army thrift store nearby you can pick these drills up for a song, people buy new ones when the batteries die. The drill I am using has a 21 step clutch which will protect the motor if I am not there when the table reaches the end. The lowest setting seems just about right.

For a power supply I grabbed my old car battery charger. It has 2 amperage settings on the 12 volt side, 2 and 6 amps. It will also do 6 volts at 5 amps. It is fan cooled, fused, and designed to run for long periods...perfect for my needs!

For a motor controller I tried adapting the drill trigger but it just wasn't sensitive enough for the kind of speed control I wanted. I went online and found this:

http://www.electronickits.com/kit/complete/motor/k166.htm

I spent a couple hours last night soldering it up. Even with my limited electronics skills it was dead easy! Just use a multi-meter to identify the different resistors...the board has the values silkscreened on it so you know where it all goes. I tested it tonight and it runs like a champ. Left over from my days as a PC tech I have a bunch of nylon posts for mounting motherboards. I will use 4 of them to isolate the controller from the aluminum box so I don't short it out. I will also add a 12 volt fan from an old computer case to the motor/controller enclosure to keep it all cool.
 
The bi-directional pot is nice but I will be adding a power switch just in case. If you don't hit the sweet spot and get the pot in the OFF position it can sit and draw current and likely burn itself out. I like the fact that the battery charger has a meter on the face so I can see my current load. Thet will let me know if I am pushing things too hard.
"In the 60's, people took acid to make the world weird.  Now the world is weird and people take Prozac to make it normal."
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bogstandard

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Re: Mini-mill power feed on a tight budget.
« Reply #1 on: April 25, 2009, 08:10:05 PM »
Webster,

I only mentioned to Stew the other evening when we were chinwagging in the shop about power feeds, that old lead acid battery chargers make very good basic power supplies, and can be picked up for next to nothing at car boot sales. But they usually have to be mounted fairly high up as the boxes are covered in cooling slots or holes that seem to attract swarf.

I've used them to power a home made veneer saw, and my Martek drill sharpener which I fitted a motor to, instead of running it from an electric drill. No problems with them at all.


John

Offline websterz

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Re: Mini-mill power feed on a tight budget.
« Reply #2 on: April 25, 2009, 08:23:47 PM »
Webster,

I only mentioned to Stew the other evening when we were chinwagging in the shop about power feeds, that old lead acid battery chargers make very good basic power supplies, and can be picked up for next to nothing at car boot sales. But they usually have to be mounted fairly high up as the boxes are covered in cooling slots or holes that seem to attract swarf.

I've used them to power a home made veneer saw, and my Martek drill sharpener which I fitted a motor to, instead of running it from an electric drill. No problems with them at all.


John

Last time I was at the home improvement store I picked up a roll of fine fiberglass window screen to wrap all my motors with. It should do a good job of keeping the swarf out of the charger as well. Car boot sale...is that like a flea market? Row after row of folks selling rusty tools and tomatoes out of the back of their vehicles in a big parking lot? The last one I hit I picked up 3 brand new Nicholson files with handles for $2.00.

Todd (just so you all know my name)  :thumbup:
"In the 60's, people took acid to make the world weird.  Now the world is weird and people take Prozac to make it normal."
 :med:

bogstandard

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Re: Mini-mill power feed on a tight budget.
« Reply #3 on: April 25, 2009, 08:54:52 PM »
Todd,

That's it, row upon row of garbage, but sometimes with little bits of treasure to be found.

I once bought a box of what I thought was used reamers and mill cutters for 20 squid (about 30 bucks), thinking they would do for roughing out. Got them home and found dozens and dozens of brand new cutters and reamers in plastic containers in the bottom of the box, under all the junk, I'm still using a lot of them to this day.

I'm sure the pot on that board could easily be replaced with a click central off one. No guesswork then.

Bogs

Offline websterz

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Re: Mini-mill power feed on a tight budget.
« Reply #4 on: April 25, 2009, 09:18:32 PM »
Todd,

That's it, row upon row of garbage, but sometimes with little bits of treasure to be found.

I once bought a box of what I thought was used reamers and mill cutters for 20 squid (about 30 bucks), thinking they would do for roughing out. Got them home and found dozens and dozens of brand new cutters and reamers in plastic containers in the bottom of the box, under all the junk, I'm still using a lot of them to this day.

I'm sure the pot on that board could easily be replaced with a click central off one. No guesswork then.

Bogs

Yes, but that would cost extra. The ON/OFF switch I already have will work just fine. Actually I will prefer it that way. Once I get the speed just right and make a pass I can switch off the power, hand run the table back to the start, and flip on the power...speed is already set.  :dremel:
"In the 60's, people took acid to make the world weird.  Now the world is weird and people take Prozac to make it normal."
 :med:

Offline Brass_Machine

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Re: Mini-mill power feed on a tight budget.
« Reply #5 on: April 25, 2009, 09:45:37 PM »
...

Todd (just so you all know my name)  :thumbup:

Names help a lot. Thanks for sharing!

Now on to your post... Dude, you are on a roll. I haven't even had a chance to breathe and you are on to a new project  :clap: Very good! Can't wait to see what you do with it. I had thought about doing a power feed on mine... but the CNC conversion won out. I am gather the parts needed on a shoe string budget.

Eric
Science is fun.

We're all mad here. I'm mad. You're mad.

bogstandard

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Re: Mini-mill power feed on a tight budget.
« Reply #6 on: April 25, 2009, 11:20:44 PM »
OK Todd, I understand now, a cheapskate, just like me.


Bogs

Offline rleete

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Re: Mini-mill power feed on a tight budget.
« Reply #7 on: April 27, 2009, 02:25:16 PM »
Necessity is the mother of invention, but being a cheapskate is the mother of innovation!
Creating scrap, one part at a time

Offline websterz

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Re: Mini-mill power feed on a tight budget.
« Reply #8 on: April 27, 2009, 07:02:58 PM »

Names help a lot. Thanks for sharing!

Now on to your post... Dude, you are on a roll. I haven't even had a chance to breathe and you are on to a new project  :clap: Very good! Can't wait to see what you do with it. I had thought about doing a power feed on mine... but the CNC conversion won out. I am gather the parts needed on a shoe string budget.

Eric

If there is anything I can help with let me know. I have a few odds and ends laying about.

Tomorrow I have to grind my new magnetic chuck so I can get the surface grinder going...that thing needs to pay for itself. 

My next project after that will be to machine a dovetail gib fixture so I can make new ali-bronze gibs for my lathe and mill. All that cheap Chinese steel (iron, butter, whatever it is) has GOT to go.  :dremel:

Todd
"In the 60's, people took acid to make the world weird.  Now the world is weird and people take Prozac to make it normal."
 :med:

Offline websterz

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Re: Mini-mill power feed on a tight budget.
« Reply #9 on: April 27, 2009, 07:05:16 PM »
Necessity is the mother of invention, but being a cheapskate is the mother of innovation!

That would make a GREAT signature line!  :beer:
"In the 60's, people took acid to make the world weird.  Now the world is weird and people take Prozac to make it normal."
 :med: