I’ve already done the batter funnel doserless mod and have been happy with that. I’ve seen the trend towards single dose grinders and the use of bellows for clearing the chute and started wondering…
I didn’t think that bellows would work on the Robur, due to the volume of the grinding chamber and chute.
In technical terms, I thought it would need a big whoosh, not a series of small puffs. So, I figured something like a coffee press would provide sufficient whoosh. I found dimensions for the Delter and it seemed close enough in size for the job. I placed a wanted ad and found one nearby at the right price.
A factor in the process is- I wanted to keep the appearance of the grinder as close to standard as possible. I understand that there are probably more effective mods, but I really prefer the proportions and factory look of the hopper.
Another member, MDF, offered some advice and expressed interest in the result. So, here it is…..
1. Nothing fitted without modification. I needed an adapter, so I found a lump of nylon in my shed. I cut it into a rough circle, then turned it on my lathe to fit the hopper throat and end of the Delter.
2. I had the choice of either removing or cutting a hole in the hopper finger guard. I thought I’d keep it in place and used a holesaw to cut a hole through it. I’d initially tried knocking it out, but I think it may be glued. The other option I considered was to cut it out completely with a hot blade. The 3 supports for the finger guard interfered with lip running around the Delter, so I filed 3 slots in the lip to make it fit.
3. Assembly was reasonably simple, but throat in the hopper was slightly smaller at the inside (top). I’d made the adapter to suit the section I could measure, but it wouldn’t fit from inside the hopper. I had to turn it down a little more. Because the throat is not a constant diameter, I had to use some Teflon tape to pack it out. If I persist with the mod, I’ll pop in a screw or 2 to hold it in place more securely.
4. Results- Initially quite disappointing. It would definitely purge some grinds, but not really clear the chute and chamber fully. I noticed some vents on the hopper collar and taped them up. I also put an o-ring under the hopper collar when it faces on the adjustment collar. These 2 things helped reduce air leakage. I’ll work on technique and see if I can improve the results.
