Gaggia Open Portafilter - Bottomless, Lay-Flat

This portafilter is the result of my quest to reduce the number of espresso accessories on my counter. It's bottomless, fits standard Gaggia-compatible portafilter baskets, and best of all, lays down flat on the counter for one-handed prep without needing a portafilter stand or mat to tamp!

Parts:

The portafilter needs the following components: 

• Portafilter top 
  • Gaggia Open Portafilter - Share Project - PCBWay
• Portafilter bottom (handle) - pick one
• 8 M2x14 Stainless Flat Head Machine Screws
  • https://www.aliexpress.com/item/2251832181264946.html
• Basket spring clip for 58 mm portafilter
  • https://www.aliexpress.com/item/3256805703350564.html

Materials:

Variant notes:

The portafilter bottom designs vary by print difficulty/method. 

• 30, 35, 40 - notes the overhang angle (degrees). 30 degree overhang is smoother, but harder to print. The image shows the bottom of the 30 degree print (left) and the smooth os print (right). If you sand/file the bottom edge this feels as good as the os version and is much stronger.
  
• os - overhangs, with supports. Print on the handle end with a brim, 4+ wall lines as the layer orientation is weaker. Most difficult print, but fully tangent handle curves.
  
• SLS - for SLS (or maybe resin) - OpenEnd and Hollow variants are light, and imo the balance feels best when paired with an Aluminum top. The Solid variant feels better with the heavier stainless steel top. 

The slide inserts vary by height - 0 is nominal, 1 is +100 μm (locks with handle further left), -1 is -100 μm (locks with handle further right). 

M10 handle version: By request, I've added version for threaded M10 handles to the Gaggia Open Portafilter - Share Project - PCBWay page so you can CNC the portafilter head and add whatever M10x1.5 handle you'd like. It's likely to be much more expensive than the original top/bottom version but to each their own. I'm not posting files here bc it doesn't contain printed parts.

Remixing Notes: 

The current handle is fairly simple, with a focus on functionality over appearance. I've included a STEP of just the adapter portion of the handle (Portafilter_Bot_Handle_AdapterOnly) to make it easy for anyone to design their own handle :)

The portafilter top went through a number of test revisions, and should lock in nicely at 90 degrees (I use a standard-height silicone group head gasket). I don't recommend changing it, but that's up to you. 

Does this design really need 8 screws? No, but the safety margin on 4 was too low for comfort and 6 didn't match the design well imo, so 8 it is. 

License:

This is open-source under a CC BY 4.0 license, so feel free to remix, modify, or even sell portafilters. All I ask is that you properly acknowledge me when doing so. For example: 

Gaggia Open Portafilter by Loogle is licensed under CC BY 4.0

Ko-fi | If you'd like to show your appreciation and help offset development costs

Updates: 

• 2025-10-24 - linked the M10 handle version
• 2025-02-03 - added new SLS handle variants, new pic
• 2024-11-25 - added handle variants, noted testing results for PEI
• 2024-11-03 - updated handle for smooth top surface