Will Compak K8 burrs fit in 83mm Ceado? - Page 3

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

#21: Post by LObin »

buckersss wrote:Ty for the write up!

Excuse my ignorance, can you help me see the machining issues you describe in the pictures? I'm not sure I know what I'm looking for.

Is one of the bottoms bowed out a bit?

The cutting edges don't have as many knicks as my oem compaks have.

Agree they are not punchy.

I find them sweet in a fuller, but slightly toned down, not intense way. And while I don't think they are intense, I have had shots using these burrs that lingered on my tongue for an hour or more. A beautiful sensation.

Doubt it has any noticeable impact though.
The cutting edges are clean.

They seem perfectly flat to me. Tried the marker test but somehow, I couldn't get any wipe-off on the outside cutting teeth. I'm guessing the outside edge isn't the highest part of the burr.
Since I didn't need shims on the Italmill nor the HU, I'm trusting that these are not completely off.

I know exactly what you mean by that lingering taste. 2 or 3 times I have pulled the same shot that I'd pulled earlier in the morning only to taste once again that peach note that stuck the whole day long.
The HU did this as well but I also experienced having to dump in the drain the last few sips of an espresso because it was too intense. Haven't had that happened with the Boyd thus far.

Thanks again for pointing me in the right direction! ;)
LMWDP #592


#22: Post by jpboyt »

What is circled is poor machine finish left by a dull insert in a machine tool. Just as burrs get dull from "machining" coffee beans, machine tools also dull. The poor finish is caused by excessive tool pressure and the cutter is chattering. Loading and unloading. Since these, noted by price, are produced as a commodity it is not uncommon to find a burr that the carbide insert in the cutting tool could have been changed a few parts earlier. Carbide inserts are not cheap and the machine is not making chips while down for retooling.
For those that like to have the sharpest burrs possible I find that the diamond stones work great. The "stone" I am referencing is diamond grit in electroless nickel on a steel plate bonded to a plastic body. Lap the burr under running water. You can see how much material you are taking off as the straight grind lines from the surface grinder will disappear after a few tuneups. Pay attention to the cutting edges and if you start to see light reflecting back at you a radius is starting to develop. Look straight on at a dull kitchen knife and you will see the same result. The radius reflects light back no matter the angle.

I was looking at a few pics earlier in this thread, I think, and the burrs had been grinding rocks or sand. You will note the scratches in a new burr are in a straight line as this is the path of the surface grinder. Circular scratches are caused by burr touching or material harder than the steel getting between the burrs. I have a few pics of burrs that didn't last very long with sand in the beans. These aren't my "best" worst pics. Dull TiN coated burrs are handy for seeing the radius being formed at the cutting edge.


#23: Post by LObin »

Thanks for the explanation James!

I'm very pleased with the Boyt K883EL. I prefer the results over my previous SSP HU which are a $350 burr set.

Makes me wonder why Compak is not using this burr geometry anymore and instead putting in their 83mm flat grinders the more "traditional" Mazzer Major style burr... Not that the later is a bad choice but the E8 / K883EL geometry seems to give a bit more clarity and sweetness in the cup, especially with modern roasts.

Thanks again for the burrs!
LMWDP #592