The BCG800XL Smart Grinder (as well as the original BCG800 and BCG600SIL) product from Breville has a plastic impeller that sits underneath the steel burrs. Its purpose is to push the grounds out the chute that leads to the basket (or portafilter). When the impeller's blades wear down over time, the grinder begins to clog up because it can't properly expel the grounds anymore. You get clumpy grounds, or no grounds at all when it jams. Replacement becomes necessary. Breville unfortunately doesn't sell parts, and so I've custom designed my own with improvements. I believe my design to be superior to the original Breville impeller thanks to better blade geometry and the tight tolerances SLS 3D printing enables. I use my grinder daily and have found that the new impeller keeps the lower chamber more clear of coffee grounds. This improvement was a pleasant surprise, since the original impeller used to always have a cake of compacted coffee around it. Consequently, loading on the motor is reduced, and clogging becomes far less likely. I'm only a single data point, so I would love to hear your own experience after a few weeks of use. Feel free to post a comment in the Repair Guide. For detailed step-by-step repair instructions visit the relevant link here:
[*][url=https://www.ifixit.com/Guide/BCG800XL+Grinder+Jamming+due+to+Worn+Impeller/62905]BCG800XL Repair Guide[/url]
[*][url=https://www.ifixit.com/Guide/BCG600SIL+Grinder+Jamming+due+to+Worn+Impeller/96493]BCG600SIL Repair Guide (Works for the BCG400SIL also)[/url]
[i]NOTE and DISCLAIMER: 3D printed Nylon plastic is slightly porous and as such, tiny amounts of dry coffee grounds may stick onto the surface of the product during everyday use. These stuck coffee grounds will go stale but otherwise should not affect much. Stale, dry coffee is harmless but could theoretically affect flavor (Not that I've noticed in my own use but I digress). Anyway, because of this plastic porosity, Shapeways does NOT claim their 3D printed plastic items to be food-grade. It makes sense that use of porous material in contact with dairy products, liquids, meats, etc would be problematic since it would harbor bacteria. I sincerely doubt it matters with dry coffee grounds though, especially considering the BCG800XL gets stale coffee stuck all over inside it even when it's brand new. I just want you to be aware of this, since Shapeways considers it worthwhile to point out. Being only a hobbyist, offering my design to an outside manufacturer (shapeways), it's hard to compensate for this characteristic of their process and so making you aware of the same limitations that I am, is the best I can offer.[/i] This product is a custom designed upgrade to the original BCG800XL Smart Grinder impeller. It also works successfully with the original BCG800 (non-XL version) and the BCG600SIL products. Users report it works with the BCG400 also. One user reported that it does NOT fit the BCG8[b]20[/b], so be aware if you have that model.
[*]The design intentionally has very tight tolerances, so you can perfectly fit it to your unit with a very small amount of sanding. Usually it's a perfect fit out of the box, but each grinder is slightly different and so this small extra step might be necessary.
[*]If you choose the "processed" option above your impeller will go through a vibration tumbler where fine beads partially reduce the coarse graininess left by the printing process. The result is less rough, and the smoother surface reduces friction which in turn should slightly improve the flow of the ground coffee.
[*]Check the main www.shapeways.com page for promo codes. They usually offer something every week or two and it might save you a couple of bucks at checkout.
[*]If you really get stuck and need help troubleshooting you can email me here: coffeegrinderhelp[at]steadymouse[dot]com
[b]Breville Product Known Compatibility:[/b]
[*]BCG800XL : Good
[*]BCG800 : Good
[*]BCG600SIL : Good
[*]BCG400SIL : Good
[*]BES860XL : Requires rounding out of impeller center hole, and there is no disassembly guide - Otherwise good.
[*]BCG820BSSXL : *NOT COMPATIBLE* due to drive shaft geometry.
[*]BES870 : Likely to be *NOT COMPATIBLE* (unconfirmed)
[b]Studying Wear:[/b] Curious how the design holds up over time? Come see for yourself. These albums contains high-res photos of the impeller [size=13px]as time has gone on and much coffee has been ground:[/size] [size=13px]April 2017: [url=https://imgur.com/a/cVgST]After 11 months of daily use in the BCG800XL[/url][/size] May 2018: [url=https://photos.app.goo.gl/868a5ReyM2XAyjZq8]After 2 years of daily use in the BCG800XL[/url] [b]Specifications:[/b] Wondering if this impeller fits another Breville product? It'll take you a couple of measurements but here are the specs on the shapeways impeller design (v4):
[*]Total diameter (blade tip to blade tip): 44.67mm
[*]Height [z-axis] (lower base to top surface not including the pegs): 8.56mm
[*]Drive shaft hole width [x-axis]: 10.16mm
[*]Drive shaft hole length [y-axis]: 7.98mm
[*]Distance between the two pegs (center to center): 18mm
[*]Peg diameter: 4mm
[*]The cylindrical well that the impeller sits in on the BCG800XL is exactly 45mm diameter.