Introduction: Restoring a Coffee Mill, Spong No.3
I found a old coffee mill in our garage a few years ago, it was quite rusty and grimy so once I initially used it the results were quite unpleasant. The first grind of fresh coffee was gritty and the mill gave a metallic taste to the ground coffee, but with repeated use (due to the onset of caffeine addiction) the coffee became less tainted and very enjoyable. During the past summer holiday (Dec-Jan, RSA) after I had researched its history, I decided to clean and restore the mill to its former glory.
According to the links below and some other web pages, the Spong coffee mill I have is one of the early models (1886 onward) as it's makers mark reads "London" possibly making it around 100 years old! The hand crank action and massive cast conical burrs are hard to match! The No.3 mill is quite popular and will fetch a good price, sale prices $100 has been seen online for complete Spong mills in good condition. You could easily pick-up such a mill at a yard sale for $10, restore it for $5 (and use it for a lifetime) and rather than buying some crazily expensive electric grinder that will probably break in 1 year of heavy duty use anyway.
Step 1: Materials and Tools
An old, dusty, dirty, rusty coffee mill with embedded ground coffee, dust, dirt and rust!
Soapy Water, 3 basinfuls, at least.
Thinners + Rag, cleanish
Spray Paint (Clear)
*see step 4.
Step 2: Disassembly
Using the spray lubricant and screwdrivers, carefully disassemble the mill. The screws were pretty rusty, so I took my time. Remember, old English screws and threads can be difficult to fix replace, so be careful!
The photo's in step 5, Reassembly, gives more details on the mills construction.
Step 3: Cleaning
This step was less fun, about an hours worth of soaking and scrubbing was required, but the results were worth it. The mill was super dirty, I felt quite unwell having ground coffee with it for a year in its previous condition. Clean every nook and cranny, you don't want to do this again soon (or at least for the next decade/century). When your hand cant scrub any more, leave cleaned parts to dry.
Now that all the parts are washed and have dried, carefully reassemble the mill.
Step 5: Prep + Paint
From research I found the mill was painted in the assembled form and I was happy with old black and gold + white hopper original paint, thus I decided to clear coat the entire assembly. Mask off the internals and treads, hang the mill (with wire) in a well ventilated area, lightly wipe down the mill with thinners (degreasing agent) and give multiple thin coats of clear paint (no runs!).
I re-glued the one Spong sticker that started to peel off due to the soaking. (Super glue rocks!)
Step 6: Modification
The original mill came with a adjustment handle and locking nut that could change and hold the coarseness of the ground coffee produced. My mill was missing this handle + nut and original nut that catches the ground coffee. I had been using a short screw but this did not provide a fine enough grind, thus I replaced it with a longer threaded hex head bolt (still need to find a locking nut + make a custom lever arm). This allows the burrs to be tightened very strongly, then the mill can even produce fine ground espresso coffee.
Step 7: Coffee Time!
Now you have a new, (very) old coffee mill that can mill coffee for 100 more years! I hope you can find one of these old mills and restore it, my Spong mill has made a massive impact on my coffee making+drinking experience!