GDM528 wrote:LOL - clever! Have you tried it with and without the toothpicks?

Yes. Without is a jet of a mess .

Interesting. You could also insert a thin grate/clump crusher cut into a 15mm diameter disk, between the main chute and the downspout. But I see how the toothpicks can get the job done, and worst-case your espresso shot might have some 'woody' flavor notes

On an earlier chute design I had tried a mid-chute clump crusher based on thin wire. It seemed to work reasonably well - until it suddenly clogged so firmly that I had to disassemble to clear it out. So I'm a little shy to try it again, and I hope it doesn't happen to you.

The lower half of the downspout was designed to host different inserts for experimenting with crushing clumps, distributing grind, controlling mess, etc. I'm still using the 'onion dome' design shown in previous posts.

For now it's perfect. Grams in grams out with lights taps on the bellow. I consider my self lucky that I don't have a 3D printer lol.

Dash wrote:With the fine grind now it clogs totally and will not finish grinding with a total blockage. The only way I can get it to complete now is to gradually feed a few beans at a time and use the bellows during the whole grind process.
Has anyone else found this issue?

I deliberately choked my DF64 today - for science!

Grind setting of about 5 (above burr-touch) and dropped in 12g of medium-light roast all at once with the grinder off. Turned on grinder and about 4g made it into the catch-up before the beans stopping moving through the grinder. Didn't completely stop spinning, but if I cut the motor it spun down very abruptly. Bellows were stiff and even a firm pounding wouldn't make any air flow through the grinder - as if there was an air seal.

Once the grinder was sufficiently bolluxed, I looked up the exit chute. The walls of the chute were covered with a thick layer of grounds, but I could still see all the way into the grind chamber. So the exit chute was not clogged. *whew*

About a third of the beans were perpetually stuck rattling around the input to the burrs. They weren't getting captured because the burrs were full of partially ground beans. The choke point appeared to be at the input of the stock Italmill burrs. At finer grind settings the inner radius of the burrs can digest the beans faster than the outer perimeter.

This may explain the grind 'reflux' I've been experiencing at finer grind settings ever since I started using the DF64. The burrs are throwing grind back up into the feed chamber, enough to warrant brushing clean after every use. Curious if all the different burr designs behave this way...

Not clear to me why the flow completely stops. I think I'd have to unscrew the top to diagnose further. The only mitigation I've found so far, is to limit the flow of beans into the burrs. I've been picturing some sort of 3D printed insert to limit the feed rate, which might also reduce the grind reflux and improve grind uniformity.

The grinder self-cleared once I opened up the burr spacing to around 20. I was able to use the bellows to completely clear the entire path and restore normal operation.

At this point it doesn't appear to me that the new exit chute design is clogging. However, I can picture two subtle ways it might be associated with the problem: The smaller aperture of the new exit chute design may create a different air pressure buildup that is triggering a premature clog with the burrs that were already close to clogging. Or the process of disassembling and reassembling the grinder has altered the burr spacing just enough to clog at a previously working setting. I've read elsewhere that the two screws that attach the bottom base plate can affect the burr spacing.

The course of action may be to switch back to the original exit chute, but before going through that trouble I suggest confirming that the correct setting for your espresso machine is still 9.

to avoid spreading the coffee, I modified the middle piece made of GDM528 and put a grill made of 0.35mm acupuncture needles. everything flows perfectly and no trace of dirt besides the grinder



thank you @GDM528 for the wonderful idea and for the work done. Everything works perfectly

A picture with my df64 to understand where I put that piece

rayanu wrote:to avoid spreading the coffee, I modified the middle piece made of GDM528 and put a grill made of 0.35mm acupuncture needles. everything flows perfectly and no trace of dirt besides the grinder

Awesome color choice! Finish work looks perfect. Hard to tell if it's FDM or SLA.

When mine choked it clogged the exit chute completely and also filled the grind chamber after the burrs. So even though there were some beans still waiting to be ground as you noted, the main issue for me was the chute was clogged and it backed up into the grind chamber to the point of being pressure sealed and the bellows would act like a balloon and pressurize the machine but only way to clear was to disassemble. I did try to select a grind setting of 50 or so but that did not help. THis happened a few times.
I noted that I had to feed very slow few beans at a time to prevent this.
I have reverted back to original chute now with a modified declumper that was working before for me.
I have also since installed SSP HU burrs to which my bottom burr did not require alignment and the top required two pieces of double thickness foil.
Now I am able to grind 1 click above touch while feeding slowly with no issues. The grounds are fluffy and nice so I will probably stay with this for a while. Maybe if a larger diameter exit chute design comes out I may try it. I'm not able to modify the design myself.
The HU burrs seem to feed better that the Italmil TIN. Grind setting has moved a lot on the dial (zero at 1:30 o'clock now). And what I ground at 4 clicks above touch now is at 1-2 with HU's.

GDM528 wrote:See post #30 in this topic thread. Clearly an expert with their printer, results look pretty good but was labor intensive. Model wasn't designed for FDM however, so supports are required.

Thanks for the confidence but I'm certainly no expert. The Mini is generally really forgiving and just a little bit of thinking about layer lines and supports was enough to get a decent print. If an FDM printer is what you have, give it a shot!

Update on the new chute: I've been using it for some time now, the most obvious thing was that I had to grind a LOT finer with it. The zero point (burr chirp) even had seemed to move, which I don't particularly understand. I've been trying to locate the reason for this but to no avail. Alignment is still good.
What I think has happened though is that the grinds are likely more uniform now than before. Less re-grinding and general smashing of the grounds is likely occuring as the grounds are coming out of the grind chamber at a much higher rate now than before. The also seem to start exiting straight away. With the original clump crusher I would hear the burrs working for about 5s before any coffee would come out.

Espresso has been good but harder to dial in. Adjustments have more of an effect. I think this too is down to a more uniform grinds distribution with less fines.
For pourover I notice fewer fines on the bed and on the paper.

I think it's not a stretch to claim that removing the clump crusher in favor of a straight chute will turn this flat burr grinder into even more of a flat burr grinder. The characteristics are eggerated even more. Then again, my only conical was an Isomac Prox Inox that I modded and subsequently gifted to a family member so I can't compare the two side by side. But the before/after on the DF64 is pretty telling to me.