Modifying the KitchenAid KPCG100 for fun and profit

Disclaimer

KitchenAid is a wonderful company, and they make great products. This page is in no way authorized or approved by them. Following the instructions on this page will most certainly void your warranty, and will probably void the UL certification (because you're removing the "don't hurt yourself" protection). Any copyrighted terms, model numbers, names, etc. are the property of their respective copyright holders and are used without permission, in a fair use capacity. Oh, and, despite the title, I'm not making money off this - the title is a formulaic joke (do X for fun and profit) in the hacker world.

Warning

By following the instructions contained herein, you are removing some of the safety features from the grinder. These features prevent stupid people from putting their fingers inside the mechanism and getting hurt, and suing KitchenAid for their injury. By removing these features, you are counting on yourself to be smart enough to not put your fingers inside something which crushes coffee beans while it is running.

Objective

The ultimate objective to this exercise is to eliminate the bean feeding problem inherent in the design of the KitchenAid KPCG100 series of coffee grinders. This problem consists of two completely independent parts:

A safety device on the input side of the hopper causes the beans to become stuck and not always feed correctly. When this happens, getting it unstuck is an issue because of the design of the safety device (hereafter referred to as the "dogbone").
A safety device on the output side of the hopper can cause a stoppage in the expelling of the crushed beans, especially if the beans are oily (such as in dark roasts), or the air is humid. This will cause beans to stay in the grinding burrs and become ground more and more finely, resulting in a wonderful espresso grind which is horrible for drip.

Approach

The basic idea is to remove the offending components, and therefore the problem.

Safety Considerations

We will be removing two components which I take to be safety devices which are (presumably) there to stop the user from putting their fingers in the auger or grinding burrs. Therefore, one needs to be careful to NOT DO THIS. Being a somewhat adventurous and intelligent spirit who is used to dealing with dangerous pieces of machinery (firearms, power saws, and the like), I am very comfortable with the idea of personal responsibility and being the sole person responsible if I shoot myself in the foot or cut off my finger. However, not everyone feels the same way. If you do not, then you need to seriously consider doing this.

Additionally, we are cutting metal (aluminum) which is a component of a food preparation apparatus. Therefore, we need to be careful to not get any shavings in the coffee.

Anyway, without further discussion, here we go.

Tools and Equipment

You will need:

The grinder.
The cleaning brush which came with the grinder, or a similar type of small brush.
A rotary tool, such as a Dremel.
Some cut off discs designed to cut metal for said tool.
A pound of the cheapest whole bean coffee you can find. Don't worry, you won't be drinking it.
A roll of paper towels.
A pair of wire snips, or stout scissors.

First

Disassemble and clean the grinder as per the manufacturer's instructions. Do not reassemble.

The Top

Here is what we're aiming to remove. The beans hang up around the dogbone, and when you try to poke them to get them down, it doesn't work quite as well as one would like.

Okay, so what we want to do is cut off the dogbone and it's support apparatus right where it meets the base assembly.

Here is what we want it to look like afterward. I've taken a grinding stone and rounded off the parts of the casting where the dogbone used to attach so as to not leave a sharp edge on which one might cut oneself.

The offending piece, removed.

The Bottom

On later models, the plastic part on the bottom has a small piece of plastic spanning the output hole. Unfortunately, I don't have a picture of it beforehand. However, it's really simple to remove it; just take the snips and cut the piece out, then use a polishing stone on the rotary tool to smooth out the edges, so that it looks like this:

This allows the ground beans to fall freely, without clogging up the output.

Cleanup

Wash out the various parts completely, and dry thoroughly with paper towels. Let stand overnight to dry completely.

In the morning, reassemble as per KitchenAid's instructions. Take the bad coffee you bought and grind it through on various settings. Yes, the whole pound of coffee. This will help work out any of the metal filings which you might have missed.

Once that's done, take it apart and clean it as per KitchenAid's instructions. Don't use water or anything like that, just brush it out.

Conclusion

I've found that this completely eliminates output stoppages, and mostly eliminates input stoppages, excepting when there are large amounts of beans in the input hopper. However, even when the input hopper jams up, just turn off the grinder, poke the hopper with your finger, and turn it on again to clear the jam. This procedure is much easier than it used to be before modification.

Addendum - July 22, 2007

A reader of this web page writes:

If you take the single screw out of the bottom plate with the output hole in it then the plate comes off easily. Behind the plate inside the body of the grinder there are two screws that hold the finger guard assembly on. This can be removed and modified off the grinder to avoid any problems with metal filings in the grinder. A small mirror helps viewing. I ended up removing the whole guard assembly. The guard assembly retains the plastic ring that the glass hopper screws into. I then fabricated a ring out of sheet metal to retain the plastic ring. That was secured with longer screws.

He sends along a picture showing the end result:

He also sends along a picture with the piece of plastic crossing the output hole.