Coffee grinders all seem to be made with pitifully small hoppers to hold the un-ground beans. I recently purchased a Shardor coffee grinder with this (to me) problem, so I designed a Hopper Extender to increase the bean holding capacity.

Note : The Hopper Extender is designed to be a friction fit into your existing hopper, but I recommend adding a couple of small pieces of tape as an extra precaution against accidental separation.

Of course not all coffee grinders are going to have the same diameter hopper as my model, so I designed it so that it can be scaled to fit other diameters. Also, some grinders have square openings and my design will not work with those models (I guess I should have titled this almost universal).

My grinder is advertised as :

• Shardor Model CG845B
• Conical Burr Coffee Grinder, Electric Adjustable Burr Mill with 14 Precise Grind Setting for 2-12 Cups.

The ID for the mouth opening on my hopper is 110mm, so if you have the same model grinder as me, or if your grinder has the same size opening, then you can use this print as is.

Models

I designed my Hopper Extender for the largest size which would work for me, but if you like the idea and want a smaller version, I included a smaller HopperExpand03 - Hopper.stl version as well; this is identical to the larger version except the the middle square section is shorter.

It might also be possible to scale the base design vertically, but I have not tried this.

Scaling

If you need to scale this print up or down to fit your coffee grinder, then I have provided “sub-models” which you can print to test on your grinder. Use the “Insert” model to test print scaled versions to find the scaling that works best for your grinder. The Insert is designed to fit a 100mm diameter opening, so you can measure the opening on your grinder and scale up or down accordingly. Ideally, you want a friction fit, so you may have to tweak the scaling a few times to get a proper fit.

I designed the Hopper Extender print to fit my grinder hopper and lid, so if you have to scale the print then of course your hopper lid is not going to fit. For this reason, I have included two additional lid models which can be scaled to fit your scaled Hopper Extender. The two lid models are as follows :

• 01 version - rim is flush to the Hopper Extender mouth
• 02 version - rim is 2mm larger than the Hopper Extender mouth to make it easier to remove

Print Instructions

I printed using transparent PLA for maximum bean visibility. Transparent PLA is not strictly necessary since the bean level will become visible in any case when it drops to the level of the original hopper. 

The print is designed to print with a 0.3mm layer height.

Since I used transparent filament, I also made the following print settings in an effort to increase transparency :

• Speed settings
  • Perimeters = 40 mm/s
  • Small perimeters = 25 mm/s
  • External perimeters =25 mm/s
• Nozzle temperature
  • Other layers = 235 °C

CAD

The OnShape 3D CAD files for this are here :

https://cad.onshape.com/documents/752d740f981bb443dfd5300d/w/89d4613d454ca877b7c5d558/e/24b5cde876ac5c9e343eb78d