Making my Bunnzilla (Ditting 804 burrs in a Bunn)

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ira
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#1: Post by ira »

A couple of weeks back I picked up a Bunn G2 for $100, essentially perfect physical condition but what I must assume are the original burrs and it's hard to imagine how worn out they are.

Took about 3 hours to disassemble and clean the grinder. The hardest part being getting the outer burr carrier off. Turns out that the shear plate can over time raise a burr on the drive shaft and make getting the burr carrier off a problem. There are a 2 unused threaded holes in the burr carrier, perfect for a couple of bolts to act as handles. I think I put some Dow 111 on the shaft to lubricate and pushed it in and out about 100 times and then it came off. Now that I know the problem it might be possible to get a tiny stone in there to clean up the burr first.

Saturday we went buy Industrial Metals and picked up suitable chunks of aluminium and steel to make the required spacer and sometime next week I'll take the grinder to the shop and start making an aluminium spacer. The carrier is aluminium so I can't see why the spacer should need to be steel. I'm also considering making a tapered something to press into the center of the stationary burr to see if I can minimize grounds retention as there's always quite a bit of coffee there when I open it up

Today the Ditting burrs arrived so I though I'd start with pictures of those. I'll put up a picture of the really dull Bunn burrs next time I take them out.

One picture of a whole burr and then 2 close ups with different lighting. The burrs are marked top and bottom but I can's see a difference, wonder if it's just to stop stupid questions?




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JohnB.
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#2: Post by JohnB. »

The "Top" burr is fixed & the "bottom" burr turns in the 804 & that's the way I mounted them in my Bunn. We used a good grade of stainless steel for the spacer to eliminate corrosion issues & my machinist felt it was a better "food safe" choice. You are free to do as you chose but you will of course have to find a new name for your grinder if you mount the burrs backwards & cheap out on the spacer. :twisted:
LMWDP 267

ira (original poster)
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#3: Post by ira (original poster) »

I thought about stainless, but the burrs are steel so what's the point of stainless and everything else is aluminium so what's the point of steel? I will mount them properly, but given they look the same, I wonder why the marking?

Ira

Intrepid510

#4: Post by Intrepid510 »

Its a personal choice, I prefer Adamantium.

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erics
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#5: Post by erics »

The burrs are marked top and bottom but I can's see a difference, wonder if it's just to stop stupid questions?
The top burr has 15 segments and the bottom has 16.

Very nice pics !
Skål,

Eric S.
http://users.rcn.com/erics/
E-mail: erics at rcn dot com

ira (original poster)
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#6: Post by ira (original poster) » replying to erics »

I'm impressed, Never though to count segments.

No flash, manual focus, tripod and a timer. Shot at 1/4 to 1/2 second exposure. It's the only way I can figure out to shoot stuff like this. Sometimes auto focus works but not here. It's frustrating because I always need to go find the manual for the camera, Nikon 4500, does lots of stuff, but finding it is interesting.

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TomC
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#7: Post by TomC »

Ira, where are you with this project now?

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osanco

#8: Post by osanco »

JohnB. wrote:The "Top" burr is fixed & the "bottom" burr turns in the 804 & that's the way I mounted them in my Bunn. We used a good grade of stainless steel for the spacer to eliminate corrosion issues & my machinist felt it was a better "food safe" choice. You are free to do as you chose but you will of course have to find a new name for your grinder if you mount the burrs backwards & cheap out on the spacer. :twisted:
We had the same idea about the top and bottom issue, but we did totally cheap out with Delrin (food safe engineering polymer, ie plastic) first just because it was handy and then aluminum. We'll eventually make some out of stainless too.


ira (original poster)
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#9: Post by ira (original poster) »

So was there a problem with the delrin or the aluminium ones? Do you think it allowed the burr to move? Never considered delrin though I have plenty in the shop that would have worked. Any good reason you want to make a third spacer?

Ira

WSH

#10: Post by WSH »

Anyone know what purpose the "ring" serves? It looks like it may cover an opening on top and behind the "fixed" burr but, I can't see any real need for it otherwise. Or the opening behind the burr either, for that matter.

What am I missing?