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Compak K3 broken hopper

Postby EricL on Wed Feb 17, 2010 1:36 pm

Just a quick check, any K3 users suffer a broken hopper. Mine developed a crack that spread until plastic chipped off and fell into the burrs. A local shop was testing a K10 and suffered similar fractures. Have a new hopper, just curious if this is a larger problem.
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Postby GC7 on Wed Feb 17, 2010 2:26 pm

Mine developed a crack too. I believe there is a thread on this problem somewere here along with pictures but I can't find it in a quick search. Mine was not nearly as serious as yours from the description.

Chris Coffee had a replacement drop shipped from Compak and I received it the very next day. Great service.

My grinder continues to work like a charm after 1 1/2 years.
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Postby HB on Wed Feb 17, 2010 3:13 pm

From Solution to cracking Compak K10 mini hopper?

Image

Mine cracked exactly the same, however it's still in one piece and I haven't replaced it.
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Postby JohnB. on Wed Feb 17, 2010 3:16 pm

Are you tightening the hopper retaining screw against the hopper neck? That seemed like a really bad idea to me so I drilled a hole in the base for the screw to seat into like you see on the Mazzer hoppers. Hopper stays locked in but there is no stress on the plastic.
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Postby HB on Wed Feb 17, 2010 4:19 pm

No, I never tighten the hopper screw and treat all my grinders with kid gloves.

The Compak K10 has a narrower and deeper neck than the Mazzers. On one hand, the Compak's narrow/deep neck increases the depth of the bean column, so even 1-1/2 shots worth of coffee eliminates popcorning. On the other hand, it means the hopper has a narrower base fitting into the neck, which I believe leads to the hoppers cracking more frequently. For what it's worth, both the standard and mini hopper on mine cracked, but neither to the point that it separated (yet).
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Postby JohnB. on Wed Feb 17, 2010 5:33 pm

Stop drilling the crack with a 1/16" bit as soon as it started would prevent the crack from spreading. I'll keep an eye on mine but it seems odd that the crack would start in the thickest part of the hopper. How long did it take for the crack to appear in each of your hoppers?
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Postby EricL on Thu Feb 18, 2010 2:18 pm

Mine took about a year, maybe 18 months. Started out like the photo. Didn't think about drilling a stress relief. Good idea. The lid on the new hopper is very tight, to the point I'm not going to snap it in place.

For reference, mine's not locked in, but it is a snug fit. Was thinking a little mineral oil or ? to smooth the insertion. Might relieve some binding if it's there which I'm pretty sure would be the source of the stress fracture.

Initially though temperature might have played a part, but even though it's sitting next to my VBM DD, it's cool to the touch, and the sun never hits it.
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Postby JohnB. on Thu Feb 18, 2010 5:07 pm

Its surprising because the Compak hoppers, at least the small one I'm using, are thicker & less brittle then the Mazzer hoppers I've owned. What little weight the small hopper holds is supported by the thick base area that sits on the cover so there doesn't seem to be much if any stress in that area. Mine is a nice fit in the cover throat; not too tight but no slop. The grinder runs smoothly with little vibration yet the hoppers seem to self destruct?? :roll:
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