Introduction: KitchenAid Benchtop Not-A-Disc Sander

By Keith's Test Garage
About: Programmer, woodworker, problem solver, problem maker.

Typical Disc Sanders:

  • Burn end grain
  • Melt thermoplastics
  • Are too fast for flexible sanding of complex contours

Before you say "my wife will kill me" let me give you some arguments.

  • This is easily removable
  • The end of this Instructable shows a $1 dust shield
  • You can make her things, so you might live.

Before you say "Kitchen Aid will break since they're now made with plastic gears..."

  • That's false.
  • Sanding is not as tough on the motor as mixing bread dough and thick batter

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I changed the title to "Not-A-Disc Sander" after observing that the picture & title gave the idea that I turned the Kitchen Aid into a typical disc sander. There was lots of feedback like "why not just get a disc sander?" which indicated people didn't read or watch. So, to be clear, this is not a typical disc sander. It fills a particular gap very well, which I explain in this Instructable, and demonstrate in the video.

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Okay, Why the Who Wha?

As this is a bit of a foreign tool category to most of us, I hope to primarily convince you that it's indeed a new category. Secondarily, I'd like to convince you to do it.

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Let's start with Why the Wha:

I've been using a slow-speed, high-torque sander in my shop (as a lathe attachment) for the past 3-4 years and it has been a wildly useful tool. Advantages of a low-speed, high-torque, stationary sander:

  1. Greater control of the workpiece
  2. Prevents excess material being removed at once
  3. Doesn't burn end grain
  4. Doesn't melt thermoplastics. I use this thing to sand off elephant's foot on 3D-printed parts often.
  5. Aggressive finesse by use of force rather than speed (again, no end grain burning!)
  6. Enables sanding to be part of the sculpting/shaping process for items like spoons.


Ok, now Why the Who:

The KitchenAid Mixer is the perfect candidate to drive a slow-speed, high-torque sander. Not only is it the perfect candidate, it's begging to be a shop tool.

  1. It's heavy
  2. It's crazy powerful with lots of torque
  3. It has a variable speed adjuster setting
  4. It has a PTO attachment port. (in other words, it's a tractor)

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History: Previous Slow Speed Sanders I've Built/Tried/Used

Here are my previous slow-speed sander builds over the past few years that led up to the Kitchen Aid.

  • Drill - handheld: hard to control.
  • Drill - clamped in vise: Awkward to clamp, hard to control speed.
  • Variable speed right-angle grinder: Actually a decent setup, A bit too fast
  • Lathe attachment: Still a bit fast (on my lathe) but otherwise very nice.
  • 30RPM motor: Too slow.
  • KitchenAid: For spoon sculpting, the KitchenAid is, IMO, far better than any of my previous setups.

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Resources

7-minute YouTube walkthrough of the design, reason, and build:

Thingiverse for 3D Printed Parts: https://www.thingiverse.com/thing:3507813

My website for additional content outside the scope of this Instructable.


Let's get on with it!


Warning about Sanding Dust:
Unlike fairy dust, sanding dust is REAL. And BAD. Don't breathe it. There are various ways to avoid breathing sanding dust (use a dust mask, sand outside, use a filter box, capture it with a dust collector, etc) that are outside the scope of this Instructable, but I felt that at least a warning was necessary.

Step 1: Parts

There are only a few parts involved and the build is simple!

Parts List

I use the 5-minute Epoxy linked above, which I consider 3-part epoxy:

  1. Epoxy
  2. Hardener
  3. Urgency

If you don't like the encouragement to work fast, look for the 30-minute stuff.

3D Printed (or otherwise created) Parts

  1. Tapered Bearing Holder
  2. Bolt Spacer


If you have a 3D printer, download and print the 2 parts in this Thingiverse here:https://www.thingiverse.com/thing:3507813. You'll need to print with supports (I think...)


If you don't have a 3D printer:

Make them out of wood. The parts don't need to be exact, so I think you can make them without too much trouble. I attached pictures of the parts with dimensions converted to imperialish for your making ease.

Then go buy a 3D printer.

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Notice: I use affiliate links to help pay for some of the supplies used in my videos. I have a strong stance about how I will and won’t use affiliate links. Read more here: https://www.keithstestgarage.com/affiliate-usage/

Step 2: Grind the T-Bolt's Head Square

The idea here is simple:

Grind the T-Bolt's head square so it fits in the square part of the KitchenAid mixer.

Use whatever means you'd prefer. Ideas:

  1. Sandpaper or Sander
  2. File
  3. Grinder

Step 3: Assemble & Install the Driveshaft

With the bearing holder,

  1. Remove 3D print supports
  2. Push in the bearings


Then, take the bolt and put on the:

  1. Spacer
  2. Bearing holder w/ bearings
  3. Lock nut - thread *almost* all the way but not quite.

If there's a bit of wobble, take it apart and put a bit of masking tape around the threads. Then put it back together.

Install it in the mixer and give it a test spin.

Step 4: Make the Sanding Plate

Cut a square-ish piece of 1/2" Baltic Birch or MDF, and do the following to it:

  1. Mark the center
  2. Punch the center
  3. Use a Forstner bit to create a recess the depth of the T-Nut face
  4. Use a normal bit to drill a hole just large enough for the T-Nut sleeve
  5. Pound in the T-Nut (in hindsight, I'd recommend using epoxy too)


Then, spin it onto the driveshaft, check for clearance, and turn it on.

  1. Draw a circle a little less than 5"
  2. Cut it out using a band saw or jigsaw.
  3. Spin it up again and sand it smooth.
  4. Remove the disc. Pretty sweet, huh?


Attach the Velcro. Hook side.

  1. Mix epoxy
  2. Spread it on the disc (the side where you can see the T-Nut!)
  3. Place Velcro
  4. Put something heavy & flat on it while it dries
  5. After it's dry, cut out the circle.


TL;DR: Attach the things to the other thing.

Step 5: Optional: Add a Dust Shield

A $1 foam core dust shield will go a long way towards convincing your resident chef/cook/baker that this sander thing is good idea.

Here's a simple way. Feel free to modify it for a collection bin, dust collection port, etc. Oh, and let me know what you come up with.

  1. Punch a hole where the T-Bolt is sticking out
  2. Cut a larger hole
  3. Fold the sides
  4. Push it back past the attachment-holder knob
  5. Reattach attachment-holder knob
  6. Show the love of your life the extents you've gone to protect the love of their life!

Step 6: Done!

Find some sandpaper and give it a whirl!

On that note: I save my used sandpaper from the random-orbit sander and use it on this thing. Low speed, high-pressure sanding gives used sandpaper an extended life!

For what it's worth, it surpassed my expectations

Although this started out to be just a silly test, I quickly found that this is actually quite the ideal machine to drive a slow speed, high torque sander. The speed range is perfect and it doesn't bog down. I've been using my lathe the past few years, but the KitchenAid mixer's slower speeds allowed me to do some aggressive sanding of the backs of those spoons that the lathe was a bit too quick for. I no longer consider this a silly test, but rather, a legit spoon-sculpting machine.

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Thingiverse 3D Models:https://www.thingiverse.com/thing:3507813

My Website:https://www.keithstestgarage.com/2019/03/21/diy-ki...

YouTube 7-Minute Walkthrough:

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