# Compak K10 Fresh - retention



## vikingboy (Mar 11, 2013)

Bit of a boring Sunday today and being the inquisitive type, I thought I'd pull my K10 Fresh apart and see how the thing worked and try and understand the variation in grind retention some users have reported.

Some users have the rubber grind screen in place, this tends to hold a couple of grammes of coffee behind it until new coffee is pushed through dislodging the stale grinds. Some users have reported machines not having them present from the factory so not sure if its something Compak do or dealers remove them. Mine had the screen present when purchased and I thought I'd try it without it.










This is the top of the chute, you can see the screw where the screen is fitted.










this is the inside of the chute once removed.










this is the inside of the grind chamber with the exit into the chute at 12 o'clock.










The mating face to the grind chamber, you can see how the pieces mate up against each other to avoid any nasty steps.










The screen itself










Grind retention is reduced without the screen although grinds exit at a faster pace with no noticeable clumping present with the beans I had in the hopper for trials.

thats all for now, thought it might be of interest to someone looking at a big conical grinder and curious how these things work.


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## glevum (Apr 4, 2013)

excellent pictures and detail...thanks


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## El carajillo (Mar 16, 2013)

Glad to know someone else "needs" to know whats inside and how it works. Nice machine well engineered.Highly envious .


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## painty (Jul 25, 2011)

I guess someone with a lot of time and patience could polish those internal surfaces of the chute to reduce retention even further. Looks like a great grinder.


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## 4085 (Nov 23, 2012)

Yep, the perfect L1 match.......hope to be joining you soon!


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## vikingboy (Mar 11, 2013)

painty said:


> I guess someone with a lot of time and patience could polish those internal surfaces of the chute to reduce retention even further. Looks like a great grinder.


I was going to give the chute to the guy who builds my race car engines, he's bloody handy when it comes to getting smooth flow through bends and what not.

blue printed grinders, think there's a market? :-D


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## Spukey (Nov 4, 2012)

The exit shoot on the K10 looks like a race car exhaust, raw and beautiful!


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## painty (Jul 25, 2011)

vikingboy said:


> I was going to give the chute to the guy who builds my race car engines, he's bloody handy when it comes to getting smooth flow through bends and what not. blue printed grinders, think there's a market? :-D


Ah of course the inlet manifold smoothing! Yup, could well be some new customers for him soon : )


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## Southpaw (Feb 26, 2012)

Thanks for the pictures. I was hoping this grinder did away with the flat path from grind chamber to chute.


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## iroko (Nov 9, 2012)

Thanks, interesting.

Surprised that the internal surface isn't polished.


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## vikingboy (Mar 11, 2013)

I found I was having to switch my k10 on and off between grinds due to obtrusive fan noise, Im sure in a busy coffee shop or business it wouldn't be an issue but in a domestic environment is was annoying and causing some less than happy wife reactions. So being a fiddler I took a look to see what was causing all the noise. You can see from the schematics the fan attaches to the back of the case and circulates cooling air around the body of the motor.










And here's some camera shots behind the fan showing the motor body and heatsinking. You can just make out the plastic adjustment wheel at the top of the images.



















The fan itself is a cheap 12v 1.62W Sunon.










Its not mounted with any thought to noise reduction, i.e no rubber mounting grommets










having run the fan in free air it isn't too bad given the speed it rotates at. The majority of the noise comes from the vents on the rear of the K10










I considered at this stage running the fan at a slower speed and also considered modifying the rear vent to reduce noise from air turbulence. I have a number of fan speed controllers lying around from my PC building days so looked to find the best way to join one in.

Removing the bottom cover finds this little lot.










and in the bottom corner, what I was looking for, kindly labelled by the good people at Compak










Being a two wire connection, there is no motor sensing wire present so I didn't anticipate any problems having to trick any control systems into thinking the fan was running full speed which makes life easier.

I'm currently running the grinder with fan speed set at zero so its silent (when not grinding obviously) and will monitor the temperatures for safety with my data logging thermometer that will be temporarily repurposed from group head monitoring. Given the K10 grinds a double shot in around 6 seconds, I dont anticipate any temperature problems or variation in grind quality due to thermally related issues but better safe than sorry. I can't imagine my home needs will ever require me to fit the larger hopper and grind through 1kg+ of beans in a go but I may give it a try to stress test the modification.


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## ziobeege_72 (May 6, 2013)

Thanks for the picks Viking Boy. Btw how soon did you hear the fan come on pre-mod?

Just curious, as I don't think I've ever heard the fan come on in my K10 in the 15 months I've had it. Mind you I only have a half dozen shots a day and tend to switch it off after a session.


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## coffeechap (Apr 5, 2012)

on the latest ones the fan comes on immediately, is a little bit annoying but then the quality of the grind completely overwhelms that.


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## ziobeege_72 (May 6, 2013)

ah got it. I suspect for a domestic setting it would be unnecessary.


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