rainstorm wrote:@EricBNC thank you.this mod seems stable grinding. Did you try grind for espresso or what u think about it?

You are welcome - I am glad it works for you.

I personally have not tried grinding for espresso since I did not modify the stepped adjustment, which is the only limitation I see with using this device for espresso. With the mod detailed by fwtechwiz in this thread, the stepped adjustment becomes step less. A stable burr set combined with infinite settings should allow the modified Skerton to grind for espresso.

I would like to thank you for all of your info, it helped tremendously! I now have a fully modified hario skerton! Well all but the nylon insert lock nut. I would like to add my $.02... the screw insulators worked great, altho I had to order them off of amazon.com, and I drilled out the hole for the screw insulators very carefully using a 25/64" drill bit. I also made my own lower bracket like u did with the tin can lid, altho I used a stainless steel ruler I bought for $2.50 and made it with my dremmel, I drilled the hole for the burr shaft to pass threw the lower bracket using a 19/64" drill bit and I actually have to thread the shaft thru the hole it fits so precisely. As for the lid for the hopper I used "I can't believe its not butter", the smallest containers, which actually came in a 2 pack for $2.50. Also I sometimes take the handle off, and put 2 6mm stainless steel nuts in the handles place, then I put a 10mm socket on my drill and basically have an electric grinder! The trick is to thread the first nut down only 3/4 of the way down the shaft, then hold the bottom nut while tightening the top nut against it, then to get the nuts off I hold the botttom nut with needlenose pliers and just reverse my drill, making sure the socket is only on the top nut to take off the top nut, I know that sounds confusing ill take a picture later. One last thing, I really don't think that adjusting the grind size is very dificult, I just hold the burrs tight together with my fingers, then tighten the adjustment nut all the way, then I unsrew the adjustment nut 1 full turn for espresso, 1 1/2 total turns for my drip coffeemaker, and I unscrew it a total of 2 full turns for my french press, I've never found it dificult. Then I put the lock washer in place, then I slip the handle on the burr shaft, and I rest the part of the handle that you grip while cranking on my chest while I tighten down the top nut!

So I realize after reading the posts that the Skerton needs to be stabilized essentially at two points, at the top, and one as far down the steel shaft as possible without interfering with the beans going down the burr. I implemented some of the advice on this thread with some added modifications as I live in Shanghai now, and do not have access to drilling equipment or nylon spacers/screw insulators. Hope this might help others who are in the same position as me.

Disclaimer: I do not have a camera, so I am reusing some of the images in this thread and using them to better illustrate what I have done. Also, while my method works, it makes regular cleaning of the Skerton a bit of a chore, because reassembling everything takes around 15-30 minutes.

Equipment Used:

Plastic Tape (2mm)
Pen, Paper, Ruler
Scissors
7.5 mm drill piece
Semi-hard transparent/translucent plastic cover with enough flat space
Gloves

Top Stabilization: Plastic Tape instead of Nylon Spacers/Screw Insulators

First, disassemble the Skerton completely, including removing the four screws at the bottom of the burr assembly. Since I cannot find nylon spacers/screw insulators in the local equivalent of Home Depot here in Shanghai, I used plastic tape (2 mm width) and wrap it around where the nylon spacer would be beginning just below the last thread, and just wrap until you get it to fit inside the tower.

Now you have just created a "plastic tape spacer." It will be a tight fit at first and the shaft may have a hard time rotating, but once you rotate the shaft a few times, the tape will start to compress down a bit, and the fit will be perfect.

Once you do this, you will notice that there is adhesive on the top and bottom sides of the "plastic tape spacer" which will cause coffee grinds to adhere to it. To prevent that, and to make cleaning easier, I would suggest that once you get down to the right fit, remove two full rotation of the 2mm tape, and then wrap a larger tape around the area, so every time you clean, a simple wipe would do the trick or just replace the outer larger tape.

Bottom Stabilization : Adjustable Plastic Plate with Hole and Slit

Now that you have the top stabilized, the bottom will still need to be stabilized as I found out unfortunately. This means more work!

I did a modification of the metal and plastic plate suggested in this thread by EricBNC and AD. I came across two problems with both methods as I experimented with them using a plastic plate.

First, no matter how hard I try to create the hole in the middle of the plastic plate so it sits perfectly centered, when I assemble everything back together and try to grind, the inner burr rubs against the outer burr on one side. This means that either the shaft is not as centered as it should be, or the center hole on the plastic plate is not centered once assembled, or my plate fitting into the four screws messed up the centering, or the outer ceramic burr is off centered. As a result, while the grinds are slightly more uniformed than without the plastic tape, there is too much coffee bean dust that clogs up the filter and creates an overly bitter coffee taste. The workaround is to make the plastic plate adjustable, meaning make a plate that does not wrap around the four screws. See green boundary in picture below showing the outline of the plate.

Second, if you use the plastic tape/nylon spacer top stabilization method, the plate will not fit through the spacer. The plate should fit if you use the screw insulator top stabilization method, but even with the screw insulator, when you put the bottom stabilization plate into the shaft, the center hole will have to go through the threads firsts, which actually widens the center hole so that there is still some, albeit slight, horizontal movement when you begin grinding. I think the shaft underneath the threading is actually only 7.5 mm, whereas the threading is 8 mm.

This is my modification that seemed to work better for me. Metal plate is not an option as it seems to involve too much work and I have no drilling equipment. I used plastic like AD's method, but the shape of my plastic plate resembles EricBNC's method as I like to have more of the plate in contact with the inner ring once I screw everything back in. I think a wider plate like EricBNC's provides more stability to the hole.

First, sketch out how you want the plate to look like on a piece of paper (actual scale). I first used the disassembled metal ring where the four screws go in, and trace both the outer and inner circle. Second, while the metal ring is still on the paper, I put a "dot" in the screwing holes indicating where the screws are located. Now take out the metal ring, and what you have on the paper is your "working area" indicating the boundary limits to the size of the plastic plate.

Still with the paper, connect the "dots" diagonally, and the center dot that is created shows where the center hole should be located on your final plate. Now draw out the rest of the plate on paper so it resembles the green boundary in the picture below.



Next, you need to transfer your "plate sketch" to the plastic you intend to use for the plastic plate. Before doing that, you need to make the center hole in the plastic first. I found a semi-hard flat plastic cover with enough flat area from my food container and created the hole by melting it with a hot 7.5 mm drill piece that I heated over the stove wearing gloves to prevent burns. The plastic should not be too pliable as it would not be stable and firm enough to prevent the shaft from shifting horizontally when grinding. But it can't be too hard or else shaping the hole would be difficult with my melting method. Once you get the center hole, take care not to trim/widen it too much at this point as you can always do that later.

Once you have the center hole on the plastic, put it on top of the sketched paper and center the hole accordingly with the center dot on paper. Hopefully, you can see through the plastic and into your sketch. Now trace on the plastic, and then when done, cut it using scissors.

Now that you have a plastic plate cut out to size, cut a slit so you can slip the plate into steel shaft without going through the threading. Should fit tightly. If too tight, widen hole slightly. See picture above. At first, I was worried that the slit would affect the plate's stability or fit of the centering hole, but in fact, it does not.

Now just reassemble everything by putting the steel shaft (modified with the plastic tape spacer and with plastic plate slipped on) through the outer ceramic burr, and then through the tower. Now position the plastic plate accordingly making sure there is wiggle room to reposition the center hole if needbe. Then CAREFULLY put the metal ring over the outer burr, making sure the ALIGNMENT is correct and put in the four screws and then tighten the screw. (I say this because if the alignment is incorrect, you will slightly crack the outer ceramic burr when tightening, which is what happened to me. I used Super Glue to glue the cracked piece back into place.) Now put the handle and everything back together on the top, and test it out.

If you're like me, you will find that with this mod, it is super stable and there is virtually no more horizontal movement flaw that originally came with the Skerton. However, there is a new problem: the burr grinds toward one side. As I mentioned at the beginning, there are several reasons for this and none of them are definitive. To fix it, slightly loosen the four screws, and reposition the outer ceramic burr accordingly as the outer burr also can also move around slightly within the metal ring. And then tighten the screws. If the problem persists, then use a screw driver or something, and reposition the plastic plate accordingly and tighten the screws.

Centering is obviously the hardest part, because there are several things that work against centering even once you stabilized the steel shaft. This is why my mod makes disassembling and cleaning the Skerton quite a chore; once you disassemble it, you will need to spend time re-centering it all over again. The first time, it took me about 30 minutes to find the sweet spot, but it was worth it as the grinds are super uniform now. Will take picture later for y'all with my friend's camera. I intend to clean my Skerton only once a month, so I don't mind the trouble.

I agree that centering the lower burr is the hardest part, and i have been worried that if i continue to screw and unscrew the 4 screws holding the lower burr and metal plate on that the 4 screws might end up not tightening as much as they used to, or that they will start working themselves loose, because they've been screwed and unscrewed so much. ive taken those 4 screws in and out probably 6 times now, and they are alot easier to screw back in now than they were when i first took them out and put them back in.

A simpler mod for stabilizing the bottom of the spindle may be to cut a slit in a nylon bushing of the appropriate inside and outside diameters (the spindle shaft is apparently a little narrower than the threaded part at the top). Slip several of these on, so the slits don't align and then put a spring between the top and bottom bushings. The outside of the bottom bushings should rub the spindle housing and the inside of the bottom bushings should rub the spindle shaft. A tight fitting bushing warmed in boiling water to soften it may form fit itself quite nicely. I will try it and post pics once I have my grinder (ordered from Amazon).

Ok I got my skerton (actually a Kyocera CM-50) and did the top and bottom stability mods, with so many thanks to all the creative people who went before me.

For the top mod I enlarged the center of a metal washer with a hand file and then crazy glued it to the top of the plastic stem. I had to sand down the top of the stem to have a flat surface to glue to.

For the bottom mod, I ended up using a clear plastic lid. First I took off the bottom burr from the spindle by holding the top of the spindle in a clamp and using a Metric 10 wrench to take off the holding nut at the bottom of the bottom burr. There are two o-ring washers on either side of the burr to protect it. Don't lose them !

Next I drilled a hole in a plastic container lid. I started out with a drill bit that was slightly too small, and I kept using slightly bigger bits until the hole just fit the spindle shaft. Because I removed the bottom burr, there was no need to cut a slit in the plastic to get the shaft through (you can't pass the plastic over the spindle from the top, because the screw threads there are wider than the rest of the spindle, as has already been pointed out).

Next I removed the top burr holding ring, centered the top burr over the hole I drilled in the plastic, and traced its outline with a pin.

I cut out a slightly wider circle than the tracking. Now I had a plastic circle with a hole in the middle, and I trimmed it into a three spider arm piece, which I then slipped unto the spindle, before putting the bottom burr back on with the holding nut (and the o-rings, one on each side). Here is a picture.



I then reassembled the grinder, tightening the top lock nut to align the burrs, before tightening down the four bottom screws holding the bottom locking ring for the top burr. Tightening these screws locks the three arm plastic guide into place. Align the locking ring with the holes in the sides of the top burr too, or you may crack it.

And success ! Very consistent coffee ! The grinder should last a long time too. Complete disassembly is not necessary for washing, so the bottom locking ring and plastic guide don't need to be fiddled with at all.

Many thanks to all the clever ones before me who pointed the way !

I cheated and ordered the OE-PFP with the bottom stabilisation already done. In the UK the Skerton costs ~£40 + delivery, unmodified; the OE-PFP was ~£50 including delivery from the US, pre-modified. I don't have drawers full of bits nor the money for tools, so the £10 difference seemed worth it to me. That just covers the bottom stabilisation though.

In the UK you can find a lid of almost the right size on the shelves in most supermarkets. They're a bit pricey for a bit of plastic but they come with free hot chocolate:



I guess newer Skertons are shipping with different top plastic. In other peoples' pics it's translucent and the thickness of the housing in contact with the axle seems to be about 1-2mm, but the OE-PFP plastic is opaque and the housing supports about 5mm of the axle. However, the plastic seems just as soft, and the housing already leaves some wiggle room around the axle even before the plastic has been worn down. To buy time I installed a really cheap, easy, two-minute hack. In the interests of full disclosure I should point out now that this tweak is untested --- the grinder hasn't yet seen a bean.

I cut a 25mm x 30mm rectangle out of a beer can. In the long dimension I cut ~12 x 15mm long slits on one end, and ~6 x 10mm long slits on the other. This left 5mm intact, lining up with the 5mm of housing. I forgot to snap it before installing it, but imagine something like this double-sided comb with the sides lopped off:



I curled it round the axle and pushed it down inside, with the ~6 10mm teeth going first, lining up the intact 5mm with the 5mm of plastic housing. Then I spread the 12 thin teeth out radially over the outside of the housing. I pushed a rubber band over it to hold it while I taped the teeth down (if you don't do this, the locking washer's prongs catch the teeth). Here it is before taping. You can see the bracket OE installed at the bottom.



There was enough room around the edges to start with that it still turns freely now, but now there's zero play, which is a bonus. If I end up with turnings of soft beer can metal in my brew then I'll post back, but it looks solid enough for now.

Ultimately I'll probably glue a flanged metal bushing or a pipe insert into the stem --- when I come across one that costs pence rather than pounds.

Beer cans are too soft. It didn't last long. All the little spidery arms broke at the joints with my enthusiastic daily grinding, and the inner bit dropped down (you can see the 'g' of 'Carlsberg' down there):



The dust at the top is tiny metal shavings (some of which I probably drank); the rest is coffee.

I caved and bought one of these:



With (too) much love and care, I widened the hole at the top and pushed the bushing down inside:



The fit is very snug both inside and outside the bushing. It only comes out again with pliers. That'll outlast the burrs, the jar, and probably me too. There's room for more overengineering, mind. That inner burr is just not quite centred on the axle, but the nut is recessed too far to tighten accurately; conical nut, maybe? Also, the hole in the OE-installed lower bracket is just a shade wider than the axle. I'm sure I can superglue a tin-snipped, 8mm-drill-pressed can lid to it. The spring mod would be useful too, although it'll have to be a small one to go between the OE bracket and the inner burr.

"The things you own end up owning you." -- Tyler Durden

I have both top and bottom stabilization mods. I find if I press down, even a little, on the handle while grinding, the leverage provides enough force to move the bottom conical burr slightly off center, due to the flexibility of the plastic housing. When you grind be sure to just go round and round without pressing down if you can help it.