Ki/Ki Stones

Killer series of techno/tech-trance mixes “Stone Techno” presented by ArteConcerts (ArteTV . com). The music is incredible, the scenery is perfect, and the filming is top-notch.

I’d start with this mix by one of my now new favorite djs Ki/Ki. It’s got some techno and some nice tech-laced trance.

Then, this equally engaging, and very much techno, set by Ben Sims and Oscar Mulero.

The internet kicks ass. How amazing is it that this kind of quality, still relatively niche, music is becoming commonplace? With that said, this Stone Techno series is as close as it gets to spending nights at Berghain.

Ellen Allien too

Cameras and Lenses

My daughter and I have become very interested in learning more about astronomy and astrophotography. So, I have become interested in prosumer cameras again. Here, I compile a list of Sony and Canon lenses of interest for our reference.

We will add thoughts on specific lenses we end up collecting.

Sony (alpha) a7R IV (Full-Frame Mirrorless)
Pixel Size: 3.73 microns
Notable: III + I = IV ¯\_(ツ)_/¯
Cost: $$$$

Canon EOS Ra
Pixel Size: 5.34 microns
Notable: “ISO invariance”
Cost: $$$

The Ra is the “astrophotography variant” of the EOS R. This is a full-frame mirrorless Canon camera using their RF lens mount. The Ra does not have the IR-cut filter over the sensor (sorta). It allows significantly more transmission of 656 nm light, which is a red associated with “Hydrogen alpha” or “h-alpha” that is emitted by many nebulae.

Sony E-Mount

Sony SEL1635GM FE 16-35mm F2.8 GM Wide-Angle Zoom Lens
Cost: $$$

Sony SEL2470GM FE 24-70 mm F2.8 GM Standard Zoom Lens
Cost: $$$

Sony SEL70300G FE 70-300mm F4.5-5.6 G Telephoto Zoom Lens
Cost: $$
Notes: This is not the GM version (note the F-stop)
GM =

Sony SEL35F18F FE 35mm F1.8
Cost: $$

Sony SEL24F14GM FE 24mm F1.4 GM
Cost: $$$


Canon RF


Canon RF 50mm f/1.2L USM
Cost = $$$$
Use = Star Landscapes; All arounder

Canon EF

Canon EF 200mm f/2.8L II USM
Cost = $$
Use = Deepsky; General Telephopto

Using Python for Financial Data/Analyses

Ongoing Notes

Yahoo Finance one maintained an API.
However, this one is where it is at:

Basic use of yfinance:

from pandas_datareader import data as pdr
import yfinance as yf

The library is pretty deep. However, for most things, IMO, the “ticker” class is probably all you need.

aaplObj = yf.Ticker(“AAPL”)
# get dividends for 2018


Prusa i3 MK3 printer

I recently purchased an i3 mk3.
These are running notes related to setup/initial observations etc.

I. Protopasta HTPLA filaments jam.

II. Octoprint

The Einsy board has a “RPi Port” designed to allow the i3 mk3 to communicate with a Raspberry Pi Zero W via SPI and Serial.

Prusa semi-officially supports octoprint/prusa print on a Pi Zero W.

You can of course use any Pi that can run octoprint. You can even use the hardware pins. But, note, that all Pis do hardware serial a bit differently. Specifically, the UART pins can be shared with bluetooth on some boards etc.
Look up how to “enable hardware serial for **insert your pi model here**”

However, I decided to use a USB connection with stock Octoprint on a RPi 4, and I am very happy. I don’t see the need to hardwire the pins. Frankly, the performance of hardware UART across the different Pi models is all over the place.

There is a bit of FUD around on RPi4s and Octoprint — I haven’t encountered issues.

The interactions between octoprint via USB and the i3 Einsy board are fine. It just offers an alternative way to use the printer. I still feel like I have my stock printer.

Julia Ebert has some excellent notes on setting any Pi/Octoprint with the i3:

THEM soul bolts

I purchased a pair of Sean Darst pro model THEM skates from my local shop Thuro. I bought them for a friend’s son who is interested in skating. He chose the Darst skates from a small list of recommendations, based largely on the look of the skate (especially the hood liner). I set them up with a Oysi frame setup, and decided to try them out a bit, before sending them out. 

At Thuro, Gabe was nice enough to let me swap the plum soul plate for a black one. I took the previous soul off and put the new one on in store and noticed the bolts in certain spots didn’t feel like they were fully clamping down. The bolts Gabe did were fine, but many of mine were still spinning a tad. Nevertheless, the soul felt perfectly clamped on the skate. 

When I put the Oysi frame on and skated them a bit I noticed a little creaking in the toe-area. More on that, but first, I want to digress a bit. The skates feel great! I’m all but certain that I will be getting a pair myself. I thought the creaking culprit was a loose soul bolt. I tried to reset the “bridge” bolt receiver in the boot a bit and retighten, but it still was a bit loose. I thought the receiver was just stripped at the end and was preventing the bolt from fully engaging. But, I looked at the taps in the receiver and they looked fine. I tried to run an M4 tap through it just to be sure there wasn’t a stray piece of metal, and the tap was perfect. In the end, the “issue” was the bolt itself. 

The M4 bolts on the THEM soul kit are conceptually perfect. They have a standard 4mm hex-head so a skater only needs to rely on one tool. Also, there is a large untapped area (I’ll call The Flange) on the screw just before the head, so it sits better in the plastic of the soul-plate just before hitting the receiver. 


I never felt like the soul and boot weren’t connected, there is a lot of tolerance in the system they designed, especially with the bridge hardware. But, because of The Flange you can end up with a situation where you will never get a perfect grip/clamp and there will be some slop. If the bridge receiver isn’t very well centered in the boot’s hole (easy to mess up) then The Flange can rest on the countersunk plastic on the soul and dig into it a bit, preventing the screw from just clasping in all the way. This is kind of hard to describe well, but you can see the result here:


This will lead to an unstable connection as the screw is effectively in at an angle and half of its foundation is soft. When I would tighten the THEM bolt in it would spin a bit towards then end, but feel connected (this is why).

I tried to get a good image of a better centered bridge. It is slightly hard to appreciate because of the angle, but in this hole I could tighten the THEM bolt easily and the grip was very stable. There was no sign of any damage to the original countersunk plastic soul plate hole. The receiver was dead center by eye:


So, if you have some loose soul-plate bolts it is worth trying to center the bridges perfectly. Use some electrical tape, dab of epoxy, etc.  if you need. What I did, was to replace the THEM bolts with some more common 3mm TORX head bolts that come with other soul kits:

Razors style Inline Skate T-Nut Soul Frame Mounting Bolts 12 Pack Sale

I’m not in love with having to regress back to needing a second tool, but these bolts are M4 and do not have The Flange:



The head of these flange-free screws are thinner than the THEM screws, but they are tapered and form a tight grip with the plastic on the THEM soul.


The soul is LOCKED to the boot now. It feels much more stable to me, and might be an improvement for your skate too. Now, after I “test” these out a bit, my friend’s kid should be thrilled. These Darst skates look amazing, and I love the feel. I’ve been using a Seba CJ/SX boot for aggressive skating, but I think I might have to add a pair of these to my collection too:


Extra notes:

I added some Seba insoles I had from my stock CJ skates and I feel like the liner fits better for my foot. I think replacing the laces are a must, I swapped them out for some black Derby waxed laces, but the stock Seba laces would work well too.

Jamieson Wizard/Street Skating

I’m going to post a string of Wizard skating ( ) vids. I love this one by Dustin Jamieson who takes things in a slightly different direction than the “norm.” This section highlights what I find most exciting about the Wizard frames, which is that they reward confidence with new abilities. If you approach these skates as a new way of doing “your” style of skating, and push them just a bit they will show you how to weave a new style into yours.

I don’t know Dustin at all, but I can’t help but read a sense of whimsy and confidence in his skating.

Check it out here:

Throw Dustin a buck or more and buy it here:

the oysi frame (and aggressive skate wheel rockering)

This post is here to document my oysi frame wheel mix and to explain the logic behind it. Skip to the “oysi frame section” if you don’t want all the background.

Rockering Aggressive Skates
My first aggressive inline skate was the Rollerblade TRS, as it was for most people who started rollerblading in the early 90’s. My second skate was the K2 Fatty. I had a love/hate relationship with my K2s. I loved their look and frame innovations, but I hated how flat they felt and how stiff the cuff was. I was eager to loan them out to friends who wanted to try them so that I could spend a week or two with their Majestic 12s. I eventually destroyed my K2s and needed a new pair of skates. Did I get Majestic 12s? No. Instead, I chose to get a pair of K2 backyard bob’s (essentially the fatty with different colors). Why would I do this? I realized I loved the hexagonal frame spacers that let you rocker the wheels in a variety of ways. Eventually I would get a pair of Majestic 12s in a final swap, but I always missed those frame spacers.

Once I had K2s I started riding small flat wheels (55 mm or so) exclusively. The innovations K2 made to the skate frame made riding flat with little to no compromise in grinding ability possible



The K2 incorporated an “h-block” in the middle of the frame for grinding, and therefore you could ride a flat setup, or experiment, even if you couldn’t in your TRS skates. The groove was TINY by today’s standards at ~1″ or so in width, but massive when compared with the TRS.

Another great feature K2 brought was a set of hexagonal frame spacers that allowed users to change the height of each wheel relative to the others. They just assumed that since they gave aggressive skaters a viable flat riding option that they would want to push the new found agility further by rockering the front wheel a bit higher, etc. interestingly, K2 still have this “hexagonal washer system” in their UFS frames:

(Photo via be-mag forum user andreas542:

Note, in the image above, the back wheel is lower than the adjacent wheel by a small amount because the bolt hole is on different sides of the hexagon. This allows a wheel to be moved away from the h-block, or further into the frame etc.

I used the hexagon system to give the skate a slight forward tilt of about 3 mm or so by progressively going from lowest in the back to higher in the front. After wearing a new set of wheels a bit, I would end up with what felt like a very stable, yet dynamic skate. I could just apply my weight naturally to the skate and the wheel base felt normal, but if I positioned my weight more in the back or front I could get a slight rocker and turn very quickly etc. Also, this tilt helped make the K2 skate (which was flat) feel a bit more like the TRS and the Majestic 12 without a squishy heel orthotic in. With that said, getting a tilt was not the main attraction to the K2 rocker system, it was being able to rocker the wheels in general.

The Wizard frame implements a tilt and natural wheel rocker in an ideal way, and in a free-skate format where its utility is maximized:Screen Shot 2019-01-03 at 10.29.05 PM.png
(image via Thuro:

Conceptually, rockering anyway that feels good for you can be achieved with different wheels, but the available mix of commercially available wheel profile and diameters limit the options.

The Oysi Frame
If you aren’t familiar with the Oysi frame, it has been described better elsewhere, in particular by the creator of the frame:

The key features of the Oysi frame are:
a) Longer wheel base.
b) Massive grind block area.
c) Lower and recessed middle wheels.
d) Higher outer wheels.
e) Incredible injection molding (the plastic is fast).

There is ~13 mm height difference between the outer and inner wheels. The most common wheel setups I’ve seen used are:

a) 72 mm Go Project wheels on the outer spots + 60 mm Go Project (or UC) wheels in the center. This gives a very slight banana rocker (very slight).
b) 68 mm UC Richie Eisler wheels on the outer spots and 54 or 55 mm Eulogy wheels in the center spots (to get a true flat or slight rocker).

I wanted to see if I could use the hi/lo arrangement of the Oysi frame and available wheel options to get a 3.5 mm tilt and a bit of a natural rocker like the Wizard frame has, and I used to do with my K2s. Because the wheel base in much longer on the Oysi than old K2s I was expecting that the benefits of this kind of rockering would be more pronounced.

First, just to be clear about the Oysi frame’s characteristics this is a true-to-scale figure of what installing four 68 mm would give us:Screen Shot 2019-01-03 at 11.05.35 PM.png
Notice how the wheels bump into each other and there is a massive difference in height. There is a 13 mm difference between the height of the middle and outer wheels, so the gap between the bottom of the outer wheels and the ground is half of the axle differences, so there is a 6.5 mm rocker.

Thus, to get a flat setup from the Oysi we do the following:

Screen Shot 2019-01-03 at 11.11.22 PM.png
Because we need to close a 13 mm diameter gap, we put 55 mm wheels in the middle. The 55 mm wheel is a popular aggressive skate wheel diameter and Undercover, Ground Control and Eulogy make 55 mm wheels in 89 to 92A durometers.

The same thing can be achieved with the 72/60 combo and it results in a very useable ~0.5 mm rocker. This is because there is an axle height difference of 13 mm, but this combo accounts for 12 mm of that with the diameter differences. The amount of rocker is half of the 1 mm difference, because half goes to the top of the wheels and half to the bottom.

Screen Shot 2019-01-03 at 11.20.36 PM.png

Now, if we want a 3.5 mm tilt we can calculate a slope factor, and then use that to determine how to scale wheel diameters from the 4th wheel (the wheel under our heel) to the 1st, despite the fact that there are two different distance gaps we are working with (i.e. the distance between wheels 3 and 2 is larger than 4-3 and 2-1). The Oysi frame has a length of 281 mm from the middle of the 4th and 1st wheel (see first figure) so to get the slope we take dy/dx where dy (height difference) is 3.5 mm and dx (the length) is 281 mm. This is a slope (k) of 0.0125 mm/mm (clearly the units cancel, but the concept is important so I keep them).

Now, the outer wheel choices are easy because that distance is fixed and we know how much difference we want. If we used the 72 mm and 68 mm wheels, we would have a 4 mm diameter difference, but half of that is the tilt which would be 2 mm. A better choice would be the 72 mm and a 65 mm wheel. That combination would be a 7 mm diameter difference, which if we cut that in half, we get our 3.5 mm tilt. Go Project makes a nice 65 mm wheel.

The harder choices are the center wheels, and we have to use our slope factor for those. The distance between the 4th (back; 72 mm) wheel and the 3rd wheel is 66.44 mm, which means 5.56 mm of length. We can get the diameter of the 3rd wheel that we should get to maintain the tilt by scaling the 66.44 mm by the slope and also subtracting the 13 mm axle difference.

Next Wheel Diameter = (Last Diameter * (Last Diameter * Slope)) – Axel Difference

If we do this sequentially for all wheels we get the following:

Screen Shot 2019-01-03 at 11.47.42 PM.png

There are no 57.3 mm or 53.7 mm wheels commercially available, but there are 57 and 54 mm Eulogy wheels. Interestingly enough, the difference between the actual diameters we can get and the ideal wheels to keep the 3.5 mm plane are the same (300 um), but in different directions. This will result in an interesting 0.3 mm rocker. When I sketched this out I wasn’t certain I would notice the rocker, or if it would be pleasant, as I don’t know what tolerances to expect. Nevertheless, if you compare the predicted rocker from the asymmetric setup (example 2; blue line) to the rocker from the 72/60 setup (example 1; black line) you can see the rocker range is close in magnitude:

Screen Shot 2019-01-03 at 11.54.38 PM.png
Again, I didn’t expect much from this because once weight is applied the differences normalize, but I have been happy to discover that I can get differences by centering my weight differently along the boot, like a relatively natural rockered skate.

Here is what the mix looks like:


The wheels from left to right (back to front) are:

* 72 mm Go Project ( – Bullet Profile

* 57 mm Jeff Dalnas Eulogy Wheels ( or – Flat Profile

* 54 mm Metatron Eulogy Wheel ( or – Flat Profile

* 65 mm Go Project Joe Atkinson Wheel ( – Flat Profile

I’m having a lot of fun skating on it. It has a slight tilt, but it feels good and stable. Also, with natural weight on the skate the rocker feels flat, but if you shift your weight more forward the back wheel touches less, and vice-versa. Thus, I feel like I’ve replicated the thing I used to love about the K2 frame, but I enjoy it more because the Oysi frame is more of a free-skate/aggressive frame given its long wheel base etc. I was skeptical of having only the back wheel as a bullet profile (conceptually if I had to use one bullet profile wheel, I’d put it in front), but I’ve been happy with it and I like dynamic it adds.

razors shift IFC compatibility

My current skate is the Razors Shift 2, which I love. I was not expecting to use the “Instant Frame Change” (IFC) system too much, but I have come to use it regularly. I did find a slight compatibility issue in some of the available soul plates that you should be aware of if you have the Shift 2, as opposed to the Shift or Cosmo. The Shift 2 added two extra recesses in the bottom of the boot in order to add t-slot m4 screws for bolting the frame to the boot.IMG_6612.jpg

This seems innocuous as the screws are optional. But, the recesses add two bumps that are ~8 mm or so and present a challenge to securing soul plates that were made before the Shift 2. Below are some images showing the problem areas.

First, the stock Shift 2 soul plate (the holes corresponding to the new m4 taps are circled in red):IMG_1709.jpg

Now a side-by-side with a v1 plate (white happens to be a Cosmo plate, but this is a concern with some Shift plates too; see below) and a v2 plate (black; not all black plates are v2):IMG_1116.JPG

This is easy enough to fix. You need to sand/Dremel out the areas I’ve shown above (blue marker outline). This will give you the clearance needed for the two new t-slot bumps to sit in the pocket. You should now be able to more easily pop a new frame on, and it will be secure. Without doing this, the bumps will prevent the soul plate from sitting flush with the boot as intended, and then you will have to force the soul slider on in an insecure way. Even if you manage to force the frame in, it will be storing potential energy like a spring. I bet it is just a matter of time before the frame pops off with just the right landing etc. For me, I couldn’t even really force the slider on. I had the most trouble getting the Cosmo soul plate and slider on as they have more glass in the plastic and flex less.

After Routing:


A black set I had to mod (same places):



I can’t find any information from Razors about these differences, but I’ve managed to piece a few things together that may help when you order extra soul plates and sliders:

The maroon and red sets were introduced post-Shift 2 and have all four holes accounted for. These do not need modification.

I do not think you can buy a gray set, like the ones that come with the Shift 2, but if you can they would be ok.

The Cosmo set is different than the Shift plates in that they have less of a soul area, but more importantly, they are made of a stiffer plastic. They are totally compatible with the Shift/Shift 2, but they need this modification to work with Shift 2.

There are two black kits in the wild. One is a darker black (close to the boot color) and those have two holes and needs to be modded. This is the one on the Razors site:

Another black kit (as I photographed above to the left of a Comso frame) looks a bit lighter black and the plastic feels a bit different, I think it has more glass in it, but this one has four holes and just works with the Shift 2 (see below). I was able to purchase both types of black kits at my local skate shop Thuro. I imagine any of the shops will look in their stock and send you either set.

The white Shift sets appear to be two hole only and will have to be modded.

Do not take this as a complaint about Razors, or the Shift skates. I love the Shift 2 and would buy it again. It’s just FYI. The fix is easy and I suggest you at least look into whether you need to, or should implement it.



pressure drop



Jimmy-Cliff-The-Harder-They-Come-album-cover-web-optimised-820.jpgThe song “Pressure Drop” by The Maytals (Toots and the Maytals) is one of my favorite songs. The track first appeared on the soundtrack for “The Harder They Come.” I’ve never seen the movie.

“Pressure Drop” is interesting musically and universally relatable. Another incredible aspect of the song is that it has been covered by so many other incredible artists, and each version is different and great in their own right. My favorites are the covers by The Clash, The Specials, and Robert Palmer.