How to know grinder burrs are worn out? - Page 2

Grinders are one of the keys to exceptional espresso. Discuss them here.
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Psyd

#11: Post by Psyd »

cajun_brew wrote: Finally, should I decide to change burrs is it as easy as unscrewing the screws and replacing with new burrs?
Uhm, one small detail; the screws that keep the burrs on a Rocky are weird. Or maybe it's the burr carriers, I dunno. the thing is, I've never gotten six out and six back in without chewing up at least one. The last time I changed burrs, I had to get a screw extractor kit to get the bottom burr off, and take the bottom burr carrier off to do it.
Make sure that you have the appropriate screwdriver tip to attempt this, and it probably isn't a bad idea to replace the screws with every burr change.
Oddly enough, the last time I replaced them I used Allen keyed cap screws, and one of them got just as stuck as it bottomed, and wouldn't come out with the proper sized key. I still have the screw extractor kit, and I'm keeping it with my grinder stuff.
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tjkoko

#12: Post by tjkoko »

Psyd wrote:Oddly enough, the last time I replaced them I used Allen keyed cap screws, and one of them got just as stuck as it bottomed, and wouldn't come out with the proper sized key. I still have the screw extractor kit, and I'm keeping it with my grinder stuff.
Perhaps with female threads require thread chasing, cleaning out (realigned) using what's called a BOTTOMING TAP from a tap and die set. Or the screws' length may be too long and deforms when they touch bottom.

Be advised that I indicated a bottoming tap as described here:

http://www.toolingu.com/definition-1502 ... g-tap.html
TJK

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Randy G.

#13: Post by Randy G. »

I changed the burrs in my Rocky twice while I owned it and never had a problem with the screws.
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Psyd

#14: Post by Psyd »

I changed the burrs on two different Rockys and had trouble both times. I used the stock screws, and both were the first time that the screws were removed since they left the factory. Both times I cleaned the machines, including the threads, and the last time I tried removing the screw immediately after putting it in and it wasn't interested in coming back out.
I do enough tech work to be familiar with how screws should go in and out, and that just ain't right. It is possible that the screws are a bit too long for the holes, but that's a manufacturing error. I should not have to use a tap nor a broken screw extractor.
It's a bad design issue.
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tjkoko

#15: Post by tjkoko »

Try using shorter screws or a slim washer (aka shim) underneath the originals.
TJK

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Psyd

#16: Post by Psyd »

I understand the potential problems (and I do appreciate the suggestions!) but I'm saying that if those are indeed issues that need addressing, Rancilio dropped the ball.
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