Instructables
Picture of Homemade Coffee Burr Grinder
This project was inspired by jeffkobi's Coffee Burr Grinder Attachment for KitchenAid Mixer.  I was perusing past contests and discovered his winning entry in the coffee contest.  I loved it.  

The power take off on the Kitchenaid mixer is definitely an underutilized resource and his use of it was inspired.  I decided to make my own version of the same concept...well...because I wanted to.

 Let's proceed shall we?
 
 
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Step 1: Stuff to get it done

I used the head of an angle grinder to transfer power from the mixer to the coffee grinder.  My coffee grinder was hiding as a peppermill right under my nose!  Some copper sheet did the job of connecting the grinder head to the coffee mill.

Step 2: We Need Power

Picture of We Need Power
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The grinder head is perfect for transferring power from the mixer but it needs some modification to adapt it.

Kitchenaid attachments all have a square drive shaft that rotates inside of a cylindrical sleeve. The drive shaft fits into a square socket in the mixer and a set screw holds everything together.  I didn't want to feel left out so I decided to emulate this arrangement.

I had a threaded drill attachment that I ground square on one end to fit into the mixer.  The other end had a male thread so I drilled and tapped a hole into the shaft of the grinder to accommodate it.  I don't have a metal lathe but my friend has a wood lathe that worked just fine for this. 
Chinasaur2 years ago
Hey, I started a Google Group to try to get people together to share some notes on DIY Kitchenaid attachments. Seems like there are a handful of people playing with this now (mostly thanks to jeffkobi's winning Instructable).

https://groups.google.com/forum/?fromgroups#!forum/kitchenaid-diy
spike3579 (author)  Chinasaur2 years ago
Great, I'll check it out.
rimar20002 years ago
Both you and me had the same idea: http://www.instructables.com/id/Grinder2grater-de-amoladora-a-rallador/

But your work is more careful, neat.
spike3579 (author)  rimar20002 years ago
I love your grater Osvaldo. Very ingenious.

I bet we would come up with some interesting inventions if we lived closer together.

I have to admit I'd been hanging onto that broken grinder for a few years because it seemed like it would be useful for something.

Any ideas for broken paper shredders? I have three of them :)
My grater has some shortcomings:
  1. I should have used the head in the opposite direction, because as it is I have to turn the handle very quickly.
  2. Many cheese flakes fall outside the container, it is easier to solve and I will finish as some other more pressing projects.
spike3579 (author)  rimar20002 years ago
I noticed how much the motor speed of the grinder is geared down compared to the output of the disk. Guess they need the extra torque. Since the disk max is 10,000 rpms I wonder how fast the motor is turning? (rhetorical, I'm sure I could look it up...)

Sorry about your hand. Power tool accidents happen so fast they are usually over before you can react to them. I'm very paranoid about damaging my eyes and ears. I rarely keep the guards on grinders. I may have to reconsider that.

We still get to see the chulengo on Sat right?
Yum... Barbecue
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Yes, on Sat, but not next Sat ;)

My hand is healing, but I can't do certain movements because it hurts.

Thanks for your concern, and put the disc cover to your grinder, soon! "Don't be stupid as me"
I like the design very much. The pepper mill burr grinder seems pretty apt for the job.

I have one caveat: consider using a pipe section made out of something other than brass. Brass looks awesome, and is esthetically an important part of your project, but brass is frequently - almost always - made with a small percentage of lead as part of the mix. This allows the alloy to deal with harsh or corrosive environments, but the lead can and does leach out of the metal. Heat exacerbates this, which is why it is a bad idea to drink hot water out of the tap. Using brass in a hand turned peppermill is potentially okay, but when you add speed, you add heat, and your coffee may end up with significant amounts of lead.

I apologize for being a buzzkill.  This really is a very cool and clever project.
spike3579 (author)  The Green Gentleman2 years ago
That's a good point. It seems like there are always unintended consequences to everything we do aren't there?

The actual grinding mechanism is steel. The grounds are not warm to the touch as they emerge from the grinder. In addition, the grounds are sitting in the lower chamber for maybe a minute. Not much time for any lead leaching to occur I think.

If lead leaching still seems like a concern the lower chamber could be removed and the grounds could fall right into a filter cone directly from the burr grinding mechanism.
Also a good point!

Mostly, I'm just bummed that brass so frequently incorporates toxic metals like lead and antimony in it. It's one of those things where I just go "huh?" We took it out of our gas because it was toxic, took it out of solder because it was toxic, but leave it in our plumbing, food processors, keys, espresso machines, jar lids and door knobs because it's pretty?

Anyway, once again, this is a cool build!
Naomii2 years ago
Nice! I have to try building one when I have time. I have a few electric grinders, but it's cool to do it the old fashioned way too. I usually check up on Coffee Grinder Reviews to see their grinders, but most of those are electric.
spike3579 (author)  Naomii2 years ago
I think you are just linking your niche site up here but if you do make a grinder post some photos.