Compak K10 WBC has landed! - Page 3

Grinders are one of the keys to exceptional espresso. Discuss them here.
ira
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#21: Post by ira »

They make stuff to prepare joints for Loctite to help it set in adverse environments which might help if you can find some, or it might not.

Ira

walt_in_hawaii

#22: Post by walt_in_hawaii »

Hey, Ira... sounds like a great idea in hindsight :) Wish I had some of that stuff a couple days ago...
I was reading up how other people were using both epoxies and cyanoacrylates on top of each other and they would be fine... but nope, not for me. Never been lucky like that.
Here's the BEFORE shot:
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And after applying the cyanoacrylate:
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So, I spent all that time making it fit super nice, with the ramp coming right up and butting up square and tight to the existing exit port on the K10... and the cyanoacrylate won't dry :( I had to wipe it off, and rinsed it off in acetone to remove it... and decided to try fitting it up to the K10 with just the epoxy on the underside holding it together... and of course the epoxy cracked. That got me a little upset.
When I get upset I tend to brute force things and just rolled out the MIG welder before cooler thoughts could prevail:
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And then a lot of cleaning up on the mill:
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It still fits very nicely... except now, the ramp doesn't butt up nicely against the exit port, the aluminum sort of melted there and left a little gap. I'm not sure if I will just fill it by letting hulk welderguy at it again, or exercise a modicum of restraint and fill with epoxy instead. I ended the night by pushing it away from me deliberately and going across to the far side of the room to glower at it menacingly. I think I better sleep on it before attacking it again.
It does go on nicely, so tight that you have to tap it into place with a hammer... but it needs a couple ears glued onto it so I can bolt this into place using the stock holes on either side of the port. Tomorrow. Still have to decide what to do about that (used to be perfect and now really ugly melted with a huge hole) ramp. phooey.

walt_in_hawaii

#23: Post by walt_in_hawaii »

I cut a small piece of an aluminum box extrusion, and from that I cut out a couple corners of it to make ears:
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The odd thing about the compak is, the exit port is sort of settled into the bottom of a cylinder made for the doser, and the mounting holes are very close to the port. So the ears have an included angle of less than 90 degrees. I've just pounded mine with a hammer to close the angle slightly. But the holes are so close to the port, that my ears proved to be too thick and I couldn't even get the screws in... so I had to cut away the ears slightly to get them closer to the port so that the screws could be inserted. As you can see, the screws are mounted into the body at a strange angle by the factory, not at 90 degrees to the surface:
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The chute is where I want it, so I added some glue to the ears and tightened into place and left it overnight to set:
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Detail of the port/chute alignment:
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I think I can cut down the chute walls, the grounds never leave the port at high velocity at all, so the chute does not have to have high walls to catch them. It will make sweeping easier. I have cleaned it out this morning and running my first batch of grinds through it to calibrate... I'm posting now because my first effort choked the machine and I'm waiting for the pressure to drop :(

walt_in_hawaii

#24: Post by walt_in_hawaii »

Hmmmm, this grinder does NOT behave remotely close to the way my mazzer SJ does. The grind is much much fluffier, which is great; but, the mazzer is retention free and the chamber responds very well to blowing out using a cake frosting bopper... very little grounds remain in the burrs. But the same bopper can't be used in the K10, and blocking the top with rags and using the bopper doesn't seem to pressurize the grind chamber enough to force out grounds. I think I will fabricate a small plug and use the bopper that way... there are some posts of folks using a blower from the bottom, from the exit port, which I tried and that seems to work well, except it sprays grounds everywhere and is a little messy. Also, inserting the bulb's nozzle into that port while the huge chompers are moving is a bit unnerving...

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JohnB.
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#25: Post by JohnB. »

walt_in_hawaii wrote: there are some posts of folks using a blower from the bottom, from the exit port, which I tried and that seems to work well, except it sprays grounds everywhere and is a little messy. Also, inserting the bulb's nozzle into that port while the huge chompers are moving is a bit unnerving...
That's yet another reason why the doser is handy. Didn't you say it came with a stainless funnel?
LMWDP 267

walt_in_hawaii

#26: Post by walt_in_hawaii »

Hi John! yes, it came with a stainless funnel, a la mazzer E type. I don't like to use it, though, as I tried a couple of times and it leaves a fine powder residue on the surface of the funnel, which is easy to remove by brushing, but its one more step and I'm trying to minimize the work flow... yeah, I know, kinda picky of me to do all this instead of just brushing a little, but there's no accounting for taste :).

OK, the cap is fabricated sorta... the K10 throat opening for the funnel is 1.884" wide, so I made an aluminum cap with a step. The lower part that goes into the throat is 1.883" ish... I want to put in an O ring and haven't machined an O ring land in ages. I think I can use an R29 O ring, nominal OD is 1-7/8", which comes to 1.875" and the ring is nominal 1/8" wide... but of course the ring measures more like .134" instead of the expected .125" ... does anyone know the correct ring groove dimensions I should cut? for a loose fit... just want the pressure blast from the bopper to be directed through the grind chamber... but don't want to have to muscle the cap into the top each time I remove it, so a 'normal' O ring fit is way too tight. I think I should remove about 5 more thou off the diameter so it goes in easier...

walt_in_hawaii

#27: Post by walt_in_hawaii »

Cap and an R29 O ring...
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Machined a groove, just nominal for now; about .125x.125" and stuck in the O ring. Looks very proud, I know it won't fit but can't take the chance. Demounted it and tried it in the compak... yep, waaaay too tight. Won't go in.
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...from measuring the top of the proud O ring, it seems its about 2.20" ish... so I think I should cut the groove deeper by about 20
thousandsths? that would be about half the normal tension for an O ring fit... still probably too tight, but I can cut more after trying again...

walt_in_hawaii

#28: Post by walt_in_hawaii »

The 20 thousandths worked just fine... O ring/cap now slips into place very smoothly, velvety feel to it but still loose enough to pop in and out quickly. I also widened the groove about .010".
A hole is made in the middle for the bellows and threaded 14 tpi:
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So, ran some beans through and pumped the bopper... it doesn't work! :(
Must be due to the conical burr itself. The flat burr in the mazzer SJ cleans up very well using the puff of air... the conical burr just seems to stall the air stream, I don't detect any air pressure at the exit port :(

walt_in_hawaii

#29: Post by walt_in_hawaii »

First morning with the new ramp and cap/bopper... Kinda mixed utility. I took the cap apart again and widened the central hole, it was a bit small so I figured that was slowing down the air... I took it from what you see in the pic to 1/2" diameter. Now it does seem to blow air more easily into the K10, I don't feel resistance in the bellows when I pump it and there is a little puff at the exit port down below when I hit it. Still not real strong, though, nothing like the mazzer, which will actually blow out the grinds when I do it on that machine. On the K10 it still requires a sweep and blowing with the air jet (I'm using a 'ball' type infant's nose sucker thingy... you know, when you have newborns and you have to suck the mucuous out of their little noses, the hospital gives you a rubber ball with a long nozzle on it, like a small turkey baster... it was like $3 at walmart and is all rubber, so I don't mind if I get it too close to the vanes on the K10, it won't harm anything if it gets chewed up).

The air jet works well, but it sprays grounds willy nilly, so I guess I won't be able to cut down the sides of the chute, they are needed to direct the blown grounds into the catch cup. I am still calibrating the grind, the mazzer requires a HAIR of movement and I'm not used to the K10... I move it a HUGE amount and don't seem to get much difference :) definitely a different pitch on those threads! After making sure the final dimensions work well, I will have to send the chute out to have it cerakoted, which will probably take a couple weeks.

There is definitely a difference in taste between the mazzer SJ (flat burrs) and the K10... but initial impressions say the SJ has more sweetness. Tastes are more distinct in the K10, and grind is definitely fluffier, but I need more time to play with grind and tamp....

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JohnB.
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#30: Post by JohnB. »

walt_in_hawaii wrote: I am still calibrating the grind, the mazzer requires a HAIR of movement and I'm not used to the K10... I move it a HUGE amount and don't seem to get much difference :) definitely a different pitch on those threads!

There is definitely a difference in taste between the mazzer SJ (flat burrs) and the K10... but initial impressions say the SJ has more sweetness. Tastes are more distinct in the K10, and grind is definitely fluffier, but I need more time to play with grind and tamp....
What do you consider a "huge amount"?
LMWDP 267