After about 6 months of heavy use, I started to get really inconsistent grinds with my Skerton. I could see that the burrs were wearing out from touching each other, so I decided I had nothing to lose by trying to modify the Skerton. There are several forum posts, products, and DIY ideas for modifying the Skerton, but I wanted to try a simple, inexpensive, but effective way to keep the burrs from touching, and to increase the consistency of the grind. This modification greatly increased the quality of grind I was getting for both fine and coarse grinds.
This method uses JB Weld to create a bushing that fits the grinder perfectly.
Disclaimer: According the JB Weld Website, JB Weld is non-toxic when cured. This does not necessarily mean that it is 'food safe.' The JB Weld does not come in contact with coffee beans, however, I don't know if regular use of the grinder would slowly wear away at the JB Weld bushing, depositing JB Weld dust into the ground coffee. I recently upgraded to an electric burr grinder, so cannot say how durable this modification is (I used JB Weld on a bolt I stripped out of an engine block on a VW Bug. 11 years later it hasn't failed, so I imagine this is a pretty durable modification for a coffee grinder...).
Step 1: Supplies and Tools
Hario Skerton Grinder
Something to mix the JB Weld in.
Something to mix the JB Weld with, and to scoop into the 'well' (a popsicle stick would work well).
Vasoline (to keep JB Weld from sticking to the Lower Burr Shaft).
Piece of Wood with center hole (the hopper should be able to sit upside down on this when the Lower Burr Shaft is in place.)
Step 2: Disassemble the Grinder
1) Unscrew the Upper Burr Assembly from the hopper.
This will allow you to more easily access the 'well' that you are filling with JB Weld.
Step 3: Prepare the Lower Burr Shaft
The smooth part of the shaft is narrower than the threaded part. I added two pieces of straw and scotch tape so that the whole shaft is about the same width. If you didn't do this, you would not be able to slide the shaft in and out of the bushing you are creating.
2) Cut two pieces of straw the length of the smooth part of the shaft.
3) Cut each piece of straw down the side so you can wrap it around the shaft. Put them on the shaft.
4) Add two pieces of scotch tape to cover the the whole shaft - straw and threads.
5) Cut a second piece of straw about 6 inches long. You should be able to put it on the end of the Lower Burr Shaft.
6) Coat the Lower Burr Shaft with vaseline, or something similar. This is to prevent the JB Weld from sticking.
Step 4: Prepare the Hopper
7) Add a piece of tape to the hole in the top of the hopper. This is to help keep the JB Weld in the 'well'.
8) Place the hopper upside down on the piece of wood, and place the 6 inch piece of straw you cut into the well (it will be resting on tape you put on the other side). The straw will create a void in the JB Weld for the the shaft to replace, but also makes it easier to fill the well with JB Weld.
Step 5: Create the Bushing
9) Mix the JB Weld. I used all the contents of both tubes, but you could probably use half or even a third. You will have about 30 minutes of work time once you have mixed the JB Weld.
10) Use the mixing stick to fill the space around the 6 inch straw in the well. I built some up along the straw as well.
11) Put the Upper Burr Assembly and the Lower Burr Shaft together. Holding it upside down, put the end of the shaft in the 6 inch straw.
12) Lift the hopper up so that the 6 inch straw goes through, and the Lower Burr Shaft enters the well. Discard the 6 inch straw.
13) Set the hopper back on the wood, and make sure the two burrs are aligned correctly. Screw the Upper Burr Assembly back to the hopper.
14) Allow the JB Weld to cure.
Step 6: Finish
15) Once the JB Weld has cured, pull the Lower Burr Shaft out.
16) Remove the the straw and tape from the shaft. Discard.
17) Use a new straw to cut two more pieces for the smooth part of the shaft (like you did earlier). These will serve as a bushing to reduce the movement of the Lower Burr Shaft in the JB Weld Bushing.
18) Assemble and use.