Hacking the DF64 exit chute - Page 18

Grinders are one of the keys to exceptional espresso. Discuss them here.
GDM528 (original poster)

#171: Post by GDM528 (original poster) »

moonshine-sg wrote:Any idea where I can order magnets? or at least the size? I probably missed it , but can't seams to find the info about the magnets...
This is where I get them in North America: https://www.kjmagnetics.com/proddetail. ... 52&cat=168

It's a pretty popular size, so I'd bet there are other suppliers in your region. I sized the holes for the magnets to be very snug, to the point where I have to use a 1/8" drill bit to clean out the holes. You could drop in a slightly smaller magnet, like 3x3mm and use some epoxy or UV nail polish to secure them.


#172: Post by dis236 »

Hey Gary,

it's me again with a different issue and I was curious if you have any thoughts on it.
I've been using your chute design with the extensions and have been very happy with it so far!

A couple of weeks ago I upgraded to the SSP cast burrs, aligned them and have been pretty satisfied with the grinds.
However I've been experiencing very frequent clogging ever since the upgrade.
By frequent I mean grinding an 18g dose and the end the chute clogs up. I clean up the clog (which is very easy with a toothpick and a chopstick, thanks to you straight design), and grind the same dose again with the now clean chute. At the end of the grinding it clogs up again.

I did some experimenting the found that the clogging is very much related to bean type, grind size and dose size.
My grinder never clogged at filter settings, regardless of dose and beans.
With darker roasts clogging is more frequent even at coraser grind settings.
With lighter roasts clogging is only at fine grind settings, ususally exactly the setting that I would like to use for espresso.
Usually if I grind in smaller doses, the clogging happens less frequently.

One more thing that I should mention is that my retention also went up by a considerable amount. It was around 0.0-0.1g with the italmills and now it's around 0.1-0.9g.

Do you have any idea why the burr swap caused the grinder to clog more frequently?
I also removed the base of the grinder because I also rewrapped it and I know that can cause the motor height to change.
Do you think that can have an effect in how the grinds fly out of the grinding chamber?


#173: Post by Jonk »

I think the SSP burrs grind faster, which would make clogs more likely to happen. Perhaps try the bean feeder mod as well to slow it down some.

GDM528 (original poster)

#174: Post by GDM528 (original poster) »

Sorry to hear about the clogging issues, given that was one of the motivations behind the exit chute in the first place.

I too have observed that subtle differences in the roast can have a big impact on how the grind proceeds. Some coffees seem to produce a grind that is very good at sticking and locking to itself. The individual grind particles have jagged edges that can lock onto other grind particles and turn into a remarkably strong matrix of clogged grind. I've been able to modulate that a bit by adjusting the amount of water I mist onto the coffee before grinding - but if I go too far, I trigger a clog within the burr teeth instead.

The chute allows the grind to flow so fast that it can turn a small buildup into a full clog in just a second or two. I watch carefully during the grind, and if I see anything that looks like a potential build-up I'll lightly tap the bellows to knock it loose. I get that touching the bellows is considered a no-no for potentially affecting the burr spacing during the grind, but those springs are really strong, and my tapping is really light. Sometimes I'll even tap the metal shroud around the exit chute with the plastic handle of my portafilter to knock loose any potential buildup - gives me something to do while I wait for the grind to finish ;) I typically run about less than 10 ticks above burr-touch with a dark roast, which is very prone to clogging, so I have to pay attention.

I think I've largely dodged the clogging issue by slowing down the overall flow of beans into the grinder, using a flow restrictor described in another thread: Bean flow restrictor for DF64 You can experiment to see if that would help by slowly feeding the beans into the hopper by hand.

Where does the clog start for you, how far down the path does it go? I've been concerned about the little ridge inside the downspout where it transitions to the expansion chamber, and I've been thinking about redesigning it to eliminate the potential clog point.

0.9g retention is a lot - was that just after switching burrs, or do you still see that level of retention? Switching back and forth between filter (coarse) and espresso (fine) grind with mess with the grind that accumulates around the upper burr gasket, alternately accumulating then knocking loose grind that collects around the upper burr. I suppose that in turn can create what looks like larger fluctuations in retention, when in fact it's carryover from previous grinds. I rarely adjust my grind setting, and my retention is still under 0.1g


#175: Post by Allongedaze »

I've been thinking about some of the great solutions in this thread and wondered if it might be possible to use the DF64V metal chute with the stock DF64 with a little tweaking. I can't find exact dimensions but knowing the company I wouldn't be surprised if the exit chute is a similar size.

GDM528 (original poster)

#176: Post by GDM528 (original poster) »

Is the DF64V detachable chute sold separately? Just eyeballing the photos, it looks wider than the opening of the DF64 - so that might qualify as a lot of tweaking to trim it down. Perhaps someone with a DF64V could measure it...

Supporter ♡

#177: Post by ronner »

Gary, your chute model is one of the best mods I made to my DF64 (printed using sla). I recently bought a DF83. The chute on that seems to me to be the weakest link causing grind retention. I am debating trying to model my own. I bought the camperista chute, but it is built via PLA (very rough compared to SLA). If I do decide to build one I will post. Thanks

GDM528 (original poster)

#178: Post by GDM528 (original poster) replying to ronner »

Appreciate the props, thanks! I still consider it a minor miracle that the design actually fit properly in other people's grinders. The measurement and fitting process was laborious (took several passes), so if you can find trustworthy CAD data from someone else (camperista?) you'll get a big jumpstart on the process. It's also really nice that you can test out chute designs without having to remove the base each time.

Do you have the version with the "plasma generator"? I'm working on retrofitting the same thing into the DF64 chute design, and it would be really useful to see exactly what the factory version looks like...

Supporter ♡

#179: Post by ronner »

Gary, I have V2 so this does have the "plasma" generator. There are two electrodes that are held in by 2 small (big enough for the wire electrode) that appear to be hot glued in place. Facing the grinder with chute in front has the wires coming into the left side of chute about an inch from top. the wires drop down to base where the electronics are. I have not looked close, but I think the DF64 may be too tight on space there. Here are directions for adding the plasma gen to a version 1.
On the chute model for the DF83, interesting event. As mentioned, I bought the DF83 chute from Camperista. They also sell the STL plans. When I inquired about the plans so I could have printed via SLA they sent me the plans. Nice gesture. Great starting point but I feel any changes I make to their plans, cannot be publicly shared as it is based on their work (I could share to Camperista). Happy grinding

GDM528 (original poster)

#180: Post by GDM528 (original poster) »

ronner wrote:I have not looked close, but I think the DF64 may be too tight on space there.
Challenge accepted :)

Thank you for the video link! Appreciate that is was 1080p and able to run 0.25x speed so I could see how the electrodes were placed.

I'm thinking the most important aspect of the CAD data you have is the negative space around it: the places you can't put material in your design, that would smack into the grinder body or chute cover. STL format files are very hard to edit IMO, so I always end up drawing a new model from scratch, using the STL model as a starting point reference for hole position and tilt angle. There are still other measurements needed to create a chute that starts right at the edge of the build chamber.