Posted on September 21st, 2012
Commercial conical grinder
I picked up this grinder as a fixer-upper, there was a sad story from the previous owner which involved attempting to grind the stainless steel bolt that holds down the central burr blade. Roburs have big strong motors and reduction gearboxes, so this was enough to bend the shaft that holds the burr, leaving a non-functional grinder making very nasty crunchy noises.
To fix it, the entire grinder was disassembled and the gearbox shaft painstakingly straightened and re-machined to perfect alignment. It would have been far easier to replace that part, but they are not stocked in Australia so a replacement was very costly and months away by boat.
While I was there, I did the following mods:
- Polished grinding chamber for lower retention of ground coffee
- Stripped back and polished aluminium body
- New small-capacity hopper from perspex and machined delrin
- Dial indicator on adjustment collar to show grind size in 100ths of a m/m
- Doser modified to sweep clean
- auto-start and auto-stop switches removed
- new adjuster lever in aluminium and matching doser lid in delrin
This is now my workshop grinder, and I’m pleased with the mods. The dial indicator makes it really easy to swap back and forth between filter and espresso grinds with a high degree of precision.