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blow-cal-devs-msg - 3/2/13


Ideas for SCA blow calibration devices.


NOTE: See also the files: armor-msg, armor-chklst-msg, Fightng-Small-art, SCAweapons-msg, Wel-Rnded-Ftr-art, Sword-Fighting-art, Shield-Balanc-art.





This file is a collection of various messages having a common theme that I have collected from my reading of the various computer networks. Some messages date back to 1989, some may be as recent as yesterday.


This file is part of a collection of files called Stefan's Florilegium. These files are available on the Internet at: http://www.florilegium.org


I have done a limited amount of editing. Messages having to do with separate topics were sometimes split into different files and sometimes extraneous information was removed. For instance, the message IDs were removed to save space and remove clutter.


The comments made in these messages are not necessarily my viewpoints. I make no claims as to the accuracy of the information given by the individual authors.


Please respect the time and efforts of those who have written these messages. The copyright status of these messages is unclear at this time. If information is published from these messages, please give credit to the originator(s).


Thank you,

   Mark S. Harris                  AKA:  THLord Stefan li Rous

                                         Stefan at florilegium.org



Date: Thu, 20 Oct 2011 15:02:53 +0100

From: Taryn East <sca at taryneast.com>

Subject: [Lochac] An idea for a mechanical pell (was re: rhino-hiding)

To: lochac at lochac.sca.org


I've been off travelling for a while now, and have only just returned to

lurk the shambles.


As such I've just noticed the recent Uber Thread of Doom (UTOD) on the

subject of rhino-hiding (not to be confused with the one on inspirational equality).


I know I am very late to this "party" - but I just read through the

entire thread and have a potential solution to this problem.


But first please bear with me while I explain where I'm coming from...


I think that one of the main problems is of calibration.


Plenty of people on the UTOD talked about how heavies are supposed to hit

"medium hard"...

however "hardness" is entirely subjective.


Miles gave an example of how he considers "hard enough" to be reliant on it

coming from a "reasonably fit" vs "weak/unhealthy" person - but that itself

is subjective.

A beefy weight-lifter's idea of "fit" is very different to a scrawny

person's, is different from a middle-aged bloke suffering from "knight's



It should therefore come as no surprise that different groups have

local variations on "hard enough".


It was also said (I think Miles again) that the knights are well

calibrated and therefore just know how hard to hit.


This is demonstrably untrue.

In the UTOD, Megan described a get-together of the chiv in which they all

calibrated against each other - with several knights apparently being

surprised at being called a heavy/light hitter.


If even the knights sometimes get it wrong, how is everyone else supposed to know?


Even if the knights are perfect - how are the fighters of a tiny canton in

the middle of nowhere supposed to learn, given they may only see a knight

once a year at festival (if that)?


I figure: why not take the guessing and subjectivity out of the picture

with, you know, science :)


A minor digression:

The fencers faced a similar issue once with armour standards.

People used to test the strength of fabric armour by throwing it on the ground

and stabbing at it with a broken foil. Different people stabbed harder, some

people had "off days" and armour was let through that would not have passed

muster on a different day, or with different people.


The problem was natural human variability...


the same with "medium-hard for a fit person".


The solution for the fencers was the drop-tester.

It's a simple, mechanical device with set length with a set weight.


Now anybody, anywhere can build one and test their armour, and they know for

certain that if the armour fails/passes drop-tester A it will fail/pass

drop-tester B


It doesn't matter if it's a guildmaster or a rank newbie holding the

drop-tester, a central-lochac fencer or somebody in the middle of nowhere

who's only ever *heard* of dons - it all comes out the same.


What the heavy fighters seem to need is a mechanical hitting-strength tester.


Think of something a bit like that carnival "how hard do you hit" thing with

the bell...


The knights can get together and determine how hard is "too hard" and how

hard is "not hard enough" and everybody that uses the device can then train

to make sure they hit with calibration within the "kingdom standard range".


Now, that big bell-thing is probably not easy to replicate (or carry

around), and I know for sure there are several extremely talented engineers

on this list who may have a better solution, but I proffer my own idea

just to get the idea rolling:


Mechanical Pell:


1) Take a u-cross-section beam that's reasonably long (testing will

   determine how long it needs to be) and of internal-width X.

2) Take a cube of something heavy whose sides are also X (this makes it a

   set, pre-determined weight - say 1 kilo. It has to be heavy enough

   to be hardish to move when whacked by a "reasonably fit" person)

3) set the beam parallel to the ground at shoulder height to the combatant

4) place the cube at one end of the beam, and sticking out by a set amount (eg 2cm).

5) Have the combatant hit the cube with what they consider to be "good" strength

6) measure how far along the beam the cube has travelled.


The knights will have previously figured out (by trying it themselves) how

far along is "not far enough" and how far along is "too far".

These lengths can be marked on the beam, for quick/easy calibration-checks.


If the cube is in this range, the hit was "good" if not - then the combatant

needs more practise at calibration.




The benefit of this setup is twofold.

Firstly - anybody can check any given blow by any given person to see how they

"measure up" to kingdom standard.

Secondly - a combatant can specifically train with this implement to

improve their own calibration.


...and they can do this no matter where in the world they are located and

with whom they train.


Now, the benefits of having a calibration-trainer/tester are mostly obvious:


A) Any individual can know if they are hitting too hard or not hard enough

B) and can get better at it with practice


but there are some less-obvious others that should also accrue over time.


1) Having a fixed, kingdom-wide standard means that there will never be a

problem (or even the perception) of ongoing increase over time. This was

mentioned on the UTOD, and we are told it hasn't happened... but it's

all too easy for people to *think* that there has been no change over

time. This way we can *know for sure* (without relying on fallible

memories), and prove it to any onlookers.


2) if everybody trains to a single standard, then the majority of people

will begin to get a very good idea of just what standard is and they will

know for certain that it's not just that "our barony trains harder than your


With greater confidence, any individual may be less afraid of speaking

up when somebody deviates from that standard... which is, of course, the

whole point of the original UTOD.





Date: Fri, 21 Oct 2011 09:36:45 +1300 (NZDT)

From: Oskar der Drachen <oskar_der_drachen at xtra.co.nz>

Subject: Re: [Lochac] An idea for a mechanical pell (was re:


To: "The Shambles: the SCA Lochac mailing list"

      <lochac at lochac.sca.org>


It's an old argument, and this idea has been discussed before too! :-)


Another device that would be easier to build would be an arm device.


2 meter lengths of 4x2

1 strap hinge w screws


Disk of 12mm plywood 100mm in diameter covered in a layer of closed cell foam


3 75x12mm carriage bolts, nuts & washers

1 x 100x12mm carriage bolt, nut & washer

1 standardized compression spring - could be a easy to get car part.


Built like a set of calipers with the strap hinge at one end, other end open, with the Disk set at the strike target.? One bolt to hold the disk to the end of the strike arm, the other in the end of the other arm to act as the "clacker".


Compression spring set near the hinge end inside the caliper to keep the ends apart.


Build your prototype and take it to a big event.? Have a wide cross section of combatants come by with a wide variety of weapons to arrive at what you determine to be a "Good" blow.


Position the compression spring in the caliper, so that the "good" blow brings the caliper ends together to give you a "clack"? Not a BANG or a tap? but a "clack".


What you have is a device that can be built by the dozens with simple instructions and tools.


It can be mounted in a variety of ways, but will give a standard you can judge against.? A newbie can judge his blow against it, go fight for a half hour, and come back to see what it takes to duplicate the effort.? This can be hit with any weapon you like, to include Archery and Siege weapons to give an accurate approximation of the same "good" blow.


Not a be-all end-all? but a standard where none exists now.


Oskar der Drachen



Date: Fri, 21 Oct 2011 07:29:31 +1000

From: "Brett Hollindale" <agro at powerup.com.au>

Subject: Re: [Lochac] An idea for a mechanical pell (was re:


To: "The Shambles: the SCA Lochac mailing list"

      <lochac at lochac.sca.org>


It has been tried at Pennsic with a post, two circles on the ground and a

head high bowling ball.

You hit the bowling ball.  If it lands between the two circles it is in the

range of "good".

It doesn't work in all cases because what it measures is momentum and what

it needs to measure is energy but it's not a bad approximation.





Date: Fri, 21 Oct 2011 07:28:30 +0800

From: Columb mac Diarmata <columb.mac.diarmata at gmail.com>

Subject: Re: [Lochac] An idea for a mechanical pell (was re:


To: "The Shambles: the SCA Lochac mailing list"

      <lochac at lochac.sca.org>


On Oct 21, 2011 5:29 AM, "Brett Hollindale" <agro at powerup.com.au> wrote:

It doesn't work in all cases because what it measures is momentum and what

it needs to measure is energy but it's not a bad approximation.


Well, the energy transferred is the momentum, so that's not quite correct.

What these kind of tests fail to measure is "impact", which includes both

energy and time.


Simply put, a shove and a punch can transfer the same amount of energy and

momentum, but a punch hurts because it transfers that energy quickly. That

gives it higher impact.


This is also the difference between a shot that pushes your pell over and

one that breaks it. The example given on armour archive was a shot from Duke

Baldar that hit the ball with an almighty CRACK!... and barely made it to

the inner circle.


Even baring these limits in mind, it would be a fun experiment.





Date: Fri, 21 Oct 2011 10:49:42 +1100

From: Jacinta Reid <omnott at gmail.com>

Subject: Re: [Lochac] An idea for a mechanical pell (was re:


To: "The Shambles: the SCA Lochac mailing list"

      <lochac at lochac.sca.org>


Ooh. I think there is an app for that.


How about hanging a carpet pell of a standard construction from a chain and

mounting a smart phone (securely and safely) on the opposite side to where

the test blows are landed (or at the bottom of the pell or some other

suitable spot). An accelerometer app could measure the movement of the pell,

and the speed with which it moved, which might be enough information to

determine whether a blow was good, light or excessively hard.


Heh, one could even program the phone to say "Good!", "Light!" or "Aaaagh!

Call an ambulance!" in real time.



Date: Fri, 21 Oct 2011 11:54:39 +1100

From: bsrlee <bsrlee2 at pacific.net.au>

Subject: Re: [Lochac] An idea for a mechanical pell (was re:


To: The Shambles: the SCA Lochac mailing list <lochac at lochac.sca.org>


The swinging device is called a 'ballistic pendulum', they used to be

fairly common in shooting circles before the advent of modern

electronics made a solid state chronograph possible.


The original consisted of a tube filled with sand hanging from 2 wires.

one end having a replaceable, frangible cap. At the back there was a

track & push block. You shot into it, the projectile expended all its

energy in the sand filled tube, this pushed the tube back moving a

marker block  along the track. There was some high school level math

which allowed you to calculate the energy imparted and from that, the

velocity of the projectile after that particular rig was calibrated with

a known sample.


What it does not give is the rate of transfer of the energy, which is

what 'counts' in SCA combat.


Brusi of Orkney



Date: Fri, 21 Oct 2011 17:42:13 +1300

From: Alasdair Muckart <silver at where.else.net.nz>

Subject: Re: [Lochac] An idea for a mechanical pell (was re:


To: "The Shambles: the SCA Lochac mailing list"

      <lochac at lochac.sca.org>


On 21/10/2011, at 3:32 PM, Rob Rowland wrote:

<<< To my mind, it's virtually impossible to strike my head or face while I'm aware and fairly engaged so as to cause me serious injury. >>>


As someone who has been put out of heavy combat permanently by injuries resulting from a blow to the helm (bascinet, 12ga top, 14ga sides, good padding) while fairly engaged I assure you it is entirely possible.


Alasdair Muckart | William de Wyke | http://wherearetheelves.net


<the end>

Formatting copyright © Mark S. Harris (THLord Stefan li Rous).
All other copyrights are property of the original article and message authors.

Comments to the Editor: stefan at florilegium.org