Leather working

Making Turnshoes from the 10th – 14th century

My leather working has gotten better. I’m now attempting turnshoes, specifically the Jorvic shoe that was excavated in York. Upper is ~4oz leather, soles are ~11oz. For those who believe in proper metric it is 1.6mm upper, 4mm sole. I used VegTan for the sole, which is fine and veg tan for the upper, which is not a good choice. Upper should have a soft temper, chrome tan would be better. Soles, the softer the temper the easier the turning of the turnshoes.

Since I had no one to teach me, I found a excellent online course by Laughing Crow. I recommend it to anyone. Which gives you the option to either buy the DVD (meh), stream it online for 4 weeks (I bought this) or stream it online and download the video ( I finally bought this too, because I need to reference it occasionally).

I made a second pair using Elk hide, which technically was nicer than my first pair. However, Elk stretches and that was a big problem, as they no longer fit and are someone dangerous to wear on sloped ground. I may convert them to sandals.

Next pair will be from Buffalo hide. Further, I may teach my a class to my local SCA folks.


Basket weaving with Privet aka Broad Leaf Ligustrum Lucidum

A use for Privet

Privet is phenomenally invasive here in Austin, Texas. It is in front yards, back yards, and in most of the beltways and walking trails. It is so bad, the city parks have volunteer crews who go out and girdle the larger Privet trees and pull up the new trees. But it is a losing proposition.

I’ve always liked privet wood, as it is the only tree in Central Texas that grows strait rods. I’ve used it to make bows, arrows, hiking sticks. atlatls, and darts for atlatls. I even used it to make a chair. It is a great wood, high energy density for firewood, dense, renewable. It also coppices well, which is a real problem if you want to eradicate it.

Basket weaving

But I wanted to figure out if it was any good for basket making. So I tried to use it like willow for wickerwork, but not go, it doesn’t pass the 90 bend test, it breaks. I think because of the large brittle pith center.

But if you treat it like hazel it will make weavers! Just cut a thumb diameter sized strait rod and then cut a v-notch about a hand width from the edge of the butt end. Then bend it over your knee and the weaver will begin to pop off the rod. It will look wrinkly at first, and you may need to use your knife point to help lift it (not cut) up and then you keep bending the rod about 2 inches in front of the weaver crack and it will keep propagating.

I tested this out and used it to finish the rim of a medieval pack basket I made from trumpet vine for Gulf Wars SCA event.

Pack basket made from Trumpet vine, and a rim of privet and woven to the basket with privet weavers.
The rim was woven to the basket with privet weavers, they were damn strong and you can yank on them to tighten them down. The Rim was closed using wooden pegs thru a drill hole to cinch them together.

I will definitely be using privet more for basket making!

Note to self- Need to test if a 3 way or 4 way Cleave will work with Privet.


Rolling percent rank using R

A quest for the uncomputable it seems. I’ve lost 4 hours trying to solve this problem.

I am loading a stock ticker, and the object class is xts/zoo. I thought I’d model the percent rank problem like I did for a simple moving average:

VXX$VXX_30day_SMA<-zoo::rollmean(VXX$VXX.Adjusted, k=30, align="right")

But that didn’t work as there is no roll_perc_rank function. So I went to use rollapply with a function like:

VXX$VXX_vol_22day_pct_rank<-zoo::rollapply(VXX$VXX.Volume, width=22, FUN = percent_rank, align='left', fill = NA)

Which uses the dply::percent_rank function, but that didn’t work.

What finally worked was TTR::runPercentRank

VXX$VXX_vol_220day_pct_rank<-runPercentRank(VXX$VXX.Volume, n = 220, cumulative = FALSE, exact.multiplier = 0.5)

Since the internet doesn’t have a good page to solve this issue, I wanted to post on it. Be sure to load the TTR library first!


Ideas for building structures for cabins at Renaissance Faires

There is a strong market for lodging before a faire, be it die hard rennies, families, or handicap attendees.

But what structures works? Balance of cost, speed of construction, labor input, materials, and cooling costs for summer.

For housing for groups, you need 55sq ft per bunk bed. So 200sq ft for 6 people, 800sq ft for 26 people.

Grubenhause that is sunken into the earth provides some cooling, resistance to high winds, and look authentic.
Another Grubenhaus.
A Saxon house, but the thatch is too dangerous.

Masonry structures are more expensive, but cool, quiet, stormproof, and low maintenance

My shed of requirement. about $9k including an overkill foundation for $2,500

Earthbag houses are cost effective but more labor.


Grotesques added to Shed of Requirement

The ‘Gargoyles’ are added. But they are really called grotesques given that they do not channel rain water. I’ve used oxide paint for the bases to match. There are 4 Grotesques, each is different from the others. The smallest is in the back where there is little light. I tell people they all were the same size when I installed them.

In other good news, the water that was getting into the shed has been fixed. It was mainly splash water hitting the door and running down and trapped inside instead off away from the structure. The next heavy rain should confirm that.

Catalan vaulted stone shed.

Current TEXAS SEIR forecast. 90 days to peak.

Rt=1.2 iCFR=0.7 SEIR model

Updates on the Shed of Requirement

So the wife said I could build a shed. I began in 2016. I’ve added a vent and used a Dubrovnik style chimney in order to let moisture out when it rains. Plus, I’ve restained the door and strengthened the Attic flooring.


Building Covid 19 tool to help forecast hospital beds

What a frilling week. Market turmoil, oil crashes, and Covid arrived to come kick our asses. I chose to not sit idly by as a spectator, and instead forge a weapon (web app) that will help hospitals around the world predict the wave IN THEIR AREA and tell them how many beds they need and if they will be swamped.

It needs to predict when the wave arrives, and how many of each type of beds will be needed. Standard, ICU, and Critical. Plus, as the data for Covid gets better, the user can change the inputs easily on the webpage.

I haven’t named it officially yet, maybe call it COBE Tool – COvid Bed Estimator Tool. I will put in in Shiny at hosted.

Early results show what will happen if Covid19 burns without social distancing. 72% of America catches it.

Tools used : R, with packages Epimdr, Desolve, Shiny. The core code for generating the S E I R table is below.

times = seq(0, 450, by=1)
#paras = c(mu = 0, N = 1, beta = 1000, sigma = 365/15, gamma = 365/5)
sigma<- 1/5 # this is     The rate at which an exposed person becomes infective. Inverse of 
gamma<-1/15 #  The rate at which an exposed person becomes resistant (recovers)
paras = c(mu = 0, N = 1, beta = .1173, sigma = sigma, gamma = gamma)
start = c(S=(.999) , E=0, I=.001, R = 0.0)
#start = c(S=0.06, E=0, I=0.001, R = 0.939)
out=ode(y=start, times=times, func=seirmod, parms=paras)
#init       <- c(S = 1-1e-6, I = 1e-6, R = 0.0)
#parameters <- c(beta = 1.4247, gamma = 0.14286)
#out <- ode(y = init, times = times, func = sir, parms = parameters)
out <-

CoVid19 forecasting cumulative cases

I do a bit of competition forecasting. Almanis, Good Judgement Open, and the Hybrid Forecasting Challenge. Some are open, some you must be invited. I’ve found that I’m good at battlefield casualties and epidemiology. Here are my thoughts on CoVid19, and the chances of having greater than 100k cumulative cases by 20MAR20

Finally the Markets are realizing CoVid19 will affect the economy.

Instantaneous forecast from yesterdays increase is 20 days left *1753 new yesterday +85403=~ 120,000 cases.

The instantaneous estimate is no longer trending down, Containment is generally working in China, but CoVid19 has now gone into the wild in other countries. I think there will be no hope of <100k by 20MAR20
But the numbers are increasing more linearly than geometrically.

The real numbers for WHO cases over the last 4 weeks are:

85403 (SitRep Day 40) – not a full week
80239 (SitRep Day 36),
73332 (SitRep Day 29)
43103 (SitRep 22),
20630 (SitRep 15)

Extrapolated weekly estimate is 85403-77794 * 3 weeks left = ~108,000
This shows signs of slowing that the Chinese fight to drop Ro is working. From the model below, I show Ro to be ~1.1 to 1.2 where last week I thought it to be 1.7 roughly.

However, now that is is wild in other countries who aren’t prepared for the Draconian methods China executed. I expect the Ro to begin to rise again.

There is a slim chance to think CoVid-19 will stay below 100k cases as I’m beginning to believe the virus is currently ‘contained’ in China. Also possible is if you believe other countries will systemically under report for political ends. Iran clearly is not reporting real numbers at this time.

Of new concern is the finding previously unknown clusters, even in the USA. Of note is this is a secondary infection not primary from travelers from China. That reinforces my thinking that many second and third world countries have wild clusters established and will begin to spread fast. They may not detect them in time to add to 20MAR WHO report.

I recommend folks follow Dr Campbell on Youtube to get his input, as he has foreign health workers with first hand accounts in Iran emailing him. Those accounts reveal hundreds to thousands infected.

Another great resource is or their mobile friendly version

The quarantine’s goal is to drop the Ro number from ~2.3 down to less than 1 hopefully, but more likely 1.2 IMHO so we need to adapt that to our numbers.

My assumptions are :
1) too late for containment
2) Wild clusters are undetected in many other countries
3) Iran’s clusters are far worse than feared.
4) The reported cases will increase quasi-geometrically perhaps linearly but not exponential until 20MAR20
5) The new post quarantine Ro is still above 1.1 and below 1.5

Raw data collected via Tencent on the official numbers is
yea, its in Simplified Chinese.
-edit- English translate

An excellent model that lets you adjust inputs is here:
(using Ro ~ 1.2 ‘ Effective reproductive number with control’ fits the data best)

I encourage all to play with that model, as it shows the case load with default Ro vs post quarantine Ro and the real cases reported. More on that model here:

In all, the infections are showing to grow steadily. If CoVid-19 establishes in South America we may get to 200k quickly, not so sure if it is just the Middle East. The model now shows we’ll hit 100k, but it looks like more likely end at 120k by 20MAR.

I still think we’ll hit 100k cases by March 10.

Probability of <100k by 20MAR20 is 5%. Probability of 100k-200k by 20MAR20 is 92%, Over 200k is 3%


An Atlatl

So I’m an archer not an Atlatl guy. But since it is just a stick that throws a stick, I cut a branch, carved it up, then promptly obsessed about finding good dart material. For Texas, broad leaf ligustrum is the solution. It grows straight after copicing. I have a mott of Ligustrum in my yard so I harvested some 1/2″ poles 5 feet long and made the darts.

Atlatl v1.0