Sunday, March 4, 2012

(So you've bought a Delonghi KG89) How to get a better coffee grinder than what you paid for

First of all, I'd like to say that if you treasure your product warranty, you can stop reading right about now. The very first modification you make will void the warranty.
Still here? Good. So I bought my Delonghi KG89(KG79 is the exact same model without the brushed steel finish) about 6 months ago to replace my manual hand grinder because I started having fore-arm cramps(for a healthy young male to get fore-arm cramps is near impossible). I used it for 4 months and gave up, going back to another hand grinder. So you bought a KG89 too right? You must have read the reviews online, good for it's price, solidly built, cheap , looks good on the counter top blah blah, easy on your wallet, dusty grind, good for drip coffee. The warning klaxons should have sounded towards the last 2 points. But you bought it anyway, proving that you're an idiot, you didn't do your research, or you're cheap(like me).
Ok, enough chatter, here's the guide to hacking your grinder into a better grinder than the one you bought.
It's good to have your grinder beside you for visual reference as I took the pictures post modifications.

First off, take out the grinder insert and take a look at the 3 screws. It's a burr grinder, the fins/grooves guiding, easing, sliding the beans in gentle caress towards their imminent crushing. Wait, why are the screws there? More importantly, why are the screws doing the grinding? Remove them. Join the burr disk onto the plastic with superglue instead. Also the 3 rods came out, right? Glue it back on or remove it, your call. Now set it aside to dry for however long your superglue label says.

There. Your grinder has become a better grinder than the one you've bought. The next step will push your grinder to the limits of good coffee, but if you're not making espresso, you can stop now. Your french press will start to have less sludge and every cup of coffee you make will just taste better.
Ok, now you're getting to the tricky part. Some of the steps might be a little scary, but trust me, I took it apart to mod, and then once again to take pictures.
Remove the knobs, pry it outwards with a flat head screwdriver. The grind setting knob is a little bit tricky with the plastic snap things. But take a deep breathe and pry it out.


Notice how I've made markings around the adjustment knob, you'll see why later. Flip your grinder upside down and you notice 4 of these slots. The little plastic snap catches are here.

Now put your fingernails where the slots are. Gently pry it outwards and the outer case should be able to slide downwards now.

Look at that.

Remove the hopper that is held together with 4 screws. Easy.
Notice that you have 2 little switches that Delonghi put in because we are all idiots. They stop the motor if the hopper lid and the grind collection box is not in place. Annoying. Remove if you want(if you don't know how or don't have the tools, you can skip this step). Solder the red wire onto the PCB board directly to complete the circuit. I leave the switches there for the tactile feel when I put the hopper lid on.

Now, the part that really matters. See here, the adjustment gears. Unscrew the frame and take out this one. There is a little piece that restricts the grind adjustment to less than a full turn. Pinch it off with a pair of pliers. Congratulations, your grinder can now grind anything from a french press to true espresso(non-pressurised porta filter).

Now, you can stop here and reassemble everything, or you can make it stepless. I haven't tried grinding with huge amounts yet and I'm more comfortable with the stepped adjestment. So this is an at your own risk thing...
Remove the big white gear held by one screw. There is a little black nub held by a spring. Remove it and keep it somewhere safe in case you change your mind later. There. Stepless grind adjustment.

Now put it all back together and give it a test run(without beans), slowly tighten the grind until you hear the burrs brushing against each other, a kind of heart rending screech, immediately bring the grind size back up two steps and turn it off. This will be your lower limit. Make a marking and make sure you don't go past the mark.
There you go, your KG89 home abomination grinder has now turned into a passable espresso grinder. But do take note that home grinders in this price range can only run for about 5-10 minutes every 1 hour. The motor will eventually burn out, but if run it for more than 10 minutes without resting, you'll hurry it along to it's eventual demise.

28 comments:

  said...

Hey,

Just wanted to let you know that I just did the same to my KG79 following your post :D

I bought it a few weeks ago. While looking stuff up on the web before making my mind up about the purchase, I discovered this blog and decided that if the stock unit doesn't perform well enough, at least I could tweak it a bit, since the description made it look rather easy.

Sure enough, it wouldn't grind fine enough. Actually, after gringing the first few portions of coffee, which were okayish, I took off the grinder insert and put it back on again, which only made things worse. Maybe there was some coffee left which didn't allow it to screw back on tight enough, whatever.

So I finally thought, why not bloody adjust it?

First, I took a look at the insert. Sure enough, the screws were the most protruding part, all of them having torn flanges (is what they're called? English is not my first language, huh) from factory assembly.

Filed screw in the back, the front ones are still intact:
Image 1

But instead of just supergluing the grinding disk onto the handle, I just took a filer to the screw heads. No they seat much deeper, and I guess that having spent fifteen more minutes or so, I could have turned theam into proper flat-head screws, but I think it's good enough as it is.

Image 2

That's dealt with. Off come the knobs:
Image 3

Up comes the outer body:
Image 4

I decided not to remove the rotation limiter on the grind adjustment knob, and simply tweaked the main gear/upper grinding disk holder a few clicks towards finer grind, having removed the knob gear.

Unscrewing the knob gear holder:
Image 5

Everything worked out perfectly, the gring is now jjjust right. The disassembly went without any issues. Some of it is down to DeLonghi's engineers who seem to have designed things right, but most of it is down to your explanations, which made it an extremely easy and straightforward process! So thanks very much :)

I will be enjoying my coffee now, brewed in an espresso machine which I also had to rebuild after a pressure blow-off valve failure (which nearly got me elecrocuted in the first place). I invested more than half of its retail price into spares, having had to import them from Australia, and a complete lack of disassembly instructins left more than a few scars on its shiny metallic body. But now I have both devices fine-tuned, reassembled and workign in perfect harmony :)

Allen Lutins said...

Thank you so much for your instructions! I had the opposite problem from most people - our grind was too fine. I was prepared to hack into the device on my own, but your instructions saved me a lot of time and effort, and the result was *perfect* :)

Jacob said...

Great post! I had done this before I got to your post because those crappy plastic gears were stripped and didn't alter the grind at all. I think the previous owner probably reefed on it too hard.

However my grinder just doesn't seem to run anymore. I don't think the motor has died or anything, but am not sure what may have gone wrong. Both the lid and basket are in so it shouldn't be the safety switches. Any ideas for other electric components I could try rewiring or shorting? Maybe the timer?

Jacob said...
This comment has been removed by the author.
Jacob said...

So it turns out that somewhere along the way I broke the front knob off, and along with it snapped the board that it connects to.

http://oi40.tinypic.com/2z3ukhk.jpg

So I think I'm sunk unless there's an easy way to short the circuit around the timer control (...?)

billy.braga said...
This comment has been removed by the author.
billy.braga said...

Is there any chance you could reupload your photos ?

charles said...

Hi. I just got a KG89 and noticed the same issue with the grind being too coarse.

I thought your post was interesting, but I dont really want to void my warranty nor take the main unit apart.

I thought of another easier possible solution:

Looking at the top removable burr that rotates when you adjust the coarseness, I looked at the 3 screws that hold the metal burr against the long plastic holder.

I want the burr just to be a tiny bit closer to the bottom burr without moving the plastic holder position when its screwed back in.

So I took out the top burr holder, unscrewed the 3 screws holding the metal burr from the holder, and put 3 tiny little very flat stainless steel washers (the smallest I could find around the house) between the metal burr and the plastic housing thus moving the burr about 1mm closer to the bottom burr.. They stick out around the inside a little from the plastic housing, but its not a problem.

I then screwed it back together nice and firmly, put the setting on the coarsest setting, and retried the grinding.

I think its finer. It should be 1mm finer, the thickness of my small washers..

Im not sure because I only just did this once, and I dont really want to grind any more coffee today, but careful that you use thin little washers and put it on the coarsest setting before starting the unit otherwise Im not sure if the burrs will hit each other. (must decide which setting will cause the burrs to scrape.)

If there are any issues with the grinder, just remove the washers and send for repair..

By the way, My grinder did not have the problem where the screws initially were sticking out abnormally. The unit works ok, but just isnt grinding the coffee very fine like my Hario Hand grinder.

My second alternative, which I thought of yesterday before I read this post, was to pregrind my beans with the Delonghi, then use the conical hand grinder to make it finer. This actually seems to work with the hand grinding being very easy with the beans being preground, but now with my washers solution the problem is solved..

charles said...

I havent tried this yet, but if you think a small washer is too thick, e.g. the coarseness adjustment is now going to be too fine, and maybe worried that the top burr will hit the bottom burr, then:

It might be possible to make 3 very thin little washers out of aluminum foil...

Get a little strip of kitchen aluminum foil, bend it over on itself until its thick enough, maybe 1/2 mm, and about 2/3 cm wide.

Poke 3 holes about 1 cm apart with small screwdriver, cut just 1/2 cm around the holes with scissors, and put 3 of these where I said to put the 3 washers.

this should be thick enough to make the top burr closer to the bottom burr, but only by a few layers of foil, depending on your needs.

Martin said...

Hi Zheng,

Great write up!

Is it possible to get the photos?

They aren't loading on your blogger site.

Many thanks!

Please me at freemotion (at) gmail (dot) com with
the pictures if it's easier.

Talk Soon,

Marty

Pavel Charouzd said...
This comment has been removed by the author.
Pavel Charouzd said...

Is it possible to get the photos?
Thank you.

Pavel Charouzd said...

Is it possible to get the photos?
Thank you.

Pavol Kalinský said...

Can you please reupload your photos ? Thank you very mcuh !!!

Pavol Kalinský said...

Can you please reupload your photos ? Thank you very mcuh !!!

Tim's doodles said...

Thanks first. However, all pictures missed. Could u help to fix them? Thank you very much

Darren Smith said...
This comment has been removed by the author.
Darren Smith said...

There are some photos for the KG79 here http://geekandgrind.tumblr.com/post/17171106555/hacking-a-dehlonghi-coffee-grinder

Pete Thompson said...

Remember chaps, this is made to grind for the delonghi espresso makers and others that use a crème enhancer or pressurised porter. If you have a classic espresso machine, you have a problem that will be fixed with the above.
If you grind too much you get blockages and a bad pull but the device works perfectly for the general public using genral public machines. If you bought a special espresso machine, you spend 50% of that cost of the grinder. As my machine was £20 at the car boot, its actually double the cost of my espresso machine :¬D

Zheng said...

Sorry everyone, I didn't notice I had comments for 3 years, silly blogspot platform. Images are up!

Marcin Grzelczyk said...
This comment has been removed by the author.
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Lsg Industrial said...

yay! this is a great invention. We at Pneumatics Philippines also love making brewed coffee.

Ariel said...

Your tip on removing the screws and using super glue really made this machine produce great grind - consistent and fine enough for my pour over. Prior to this hack, all I got was a watery diluted and frankly, undrinkable slush.

I couldn't remove the case, so I couldn't proceed with the second part of your hack. But for my pour over needs, it's now as good as my ceramic hand grinder.

Thank you!

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