‘Endshock’ and flake analysis

Mac 1

We are back from our weeks holiday in Mid-Wales and knapping wise I didn’t have much more Johnstone Solutrean success. Ultimately from the two large sheets of Johnstone I took with me I produced the previously discussed Solutrean point, and lots of smaller blanks that will be suitable for arrowheads. The arrowhead blanks are a bi-product and so not relevant to this discussion, however I think it is interesting to explore where my problems lie. One problem that happened more than once was ‘endshock’ (see above image). When this piece snapped in the middle I was actually working on thinning one of the ends. This is how I ended up with the arrowhead blanks.

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A second issue that deserves attention was how I was effectively thinning the pieces. Above are five useful penetrative thinning flakes that successfully removed the original surface, however, I couldn’t produce these consistently.  The above photograph shows the ventral, or inner surface of flakes I preserved for reference, to see what was going on when it worked.

mac 3

The above image is of the first three flakes but the dorsal, or outer face, showing the amount of flat original surface successfully removed. They are organised in size order with the first being the largest and therefore most successful. This first flake is 49 mm in length and the platform, or the part of the flake that received the impact is 9 mm in length and 4 mm in width. So all the energy from the blow was transferred into the body of the blank being worked through that small area. The platform can be considered ‘plain’ in that it has not been worked in any way. Another useful analytical aspect is the ‘Platform Angle’. If the angle between the face of the platform and the dorsal surface on any flake is measured it will usually be 90 degrees or less. At any greater angle the energy of the blow would not be concentrated and therefore ineffective. The platform angle on this piece is about 70 degrees. This tells us that the energy imparted from the heavy soft hammer blow entered the piece at 70 degrees to the dorsal surface through a plain small platform. Onto the second longest flake.

 

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The second longest flake is 42 mm in length and the platform seems to be a small plain section some 4 mm by 2 mm. Emerging from the platform on the ventral surface we can see what is called an ‘Eraillure Scar’. This scar illustrates that a mini flake was removed from the main flake at the same time as the main flake was removed from the blank. For my purposes it acts as a signpost to the point of impact. Platform angle is more like 90 degrees on this one. On to the third flake.

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This one is 35 mm in length and the large erailiure scar indicates a single raised point of impact. This kind of platform is termed ‘Punctiform’, or point like, probably 2mm x 2mm, and the platform angle is again close to 90 degrees.

So how can this help us, or help me? The endshock I think is in many ways simply a symptom of a lack of attention. Firstly, the sound of a hit tells me if the platform has been correctly produced because I can hear the sound of the flake being taken off. Alternatively, if I can hear the dull thud of unstoppable antler against immovable blank then there is a potential problem. This can be exacerbated if the blank is not supported by the knapper’s body. I was guilty of both these ‘crimes’ when the above example occurred. So prepare a good platform; support the blank (perhaps by resting it on my thigh); listen for problems when I hit it. Regarding the flake analysis, it seems to confirm that a platform angle of between 70 and 90 degrees, and a sticky out point in these instances have led to long removals taking off decent flakes.

It has been busy since we came home and it has taken me a while to finish this blog post. I think I understood most of this stuff already before analysing these flakes, and so what this highlights is my movement between systematic preparation and a more intuitive percussion. Sometimes I pay attention, and sometimes I don’t, and the result is inconsistent flaking. If I can stay focused on the above points then in theory I should be able to move on a stage. I think if I can pay attention and get a better result, then my intuitive percussion will also improve.

This can be described usefully by a four stage learning model. The four stages of learning a new skill are:

  1. Unconsciously incompetent (it looks easy because you don’t know you can’t do it).
  2. Consciously incompetent (you try it and realise you can’t do it).
  3. Consciously competent (you progress by maintaining intense concentration).
  4. Unconsciously competent (you have got it and are in the zone!)

When it comes to Johnstone Solutrean points I am currently just past ‘Consciously incompetent’ and approaching ‘Consciously competent’. I was however in the zone on Saturday, but that is a different blog post!

 

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And then there were four

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I woke up early this morning with the aim of finishing the last preform, and it has turned out really well.

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Certainly the most Kimberley Point like of the bunch. It took the best part of an hour and wasn’t without its issues. An alternative title for this post might have been ‘how much platform do you need?’ This is because towards the end it is easy to run out of width. When this occurs it is necessary to become judicious with the platforms produced. It is simply a case of changing the edge angle enough to remove a flake. I seem to have got into this with this one and it has resulted in a more refined point that has serrated more easily.

This idea of producing one point per day is a really useful strategy for finding time to produce stuff. Doing so first thing in the morning is also a great way to start the day. Now breakfast.

One point per day. I am an optimist

I have just finished an epic ‘negotiation’ with a lovely liquorice coloured, 10mm thick piece of period plate glass. I started it yesterday evening, and finished it this morning. The complete process falls within a 24 hour period, but that would be what is termed ‘special pleading’. I just want to do one point per session per day. The glass is really lovely and the thickness presented some real learning opportunities.

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This was the toolkit I started with. I wasn’t at home and forgot to bring my abrading stone (mistake). This morning at home I employed the abrading stone and a piece of leather to protect my hand as by then it was getting sore.

Glass cutter and hard hammer

Because the glass was exceptional I wanted to make the most of it. This meant splitting it, and to do so I used a glass cutter and then gently hard hammered along the ‘cut’. This strategic use of modern and traditional approaches resulted in two decent sized pieces. Trust in God, and tie your camel, so to speak.

Optimistic

I have been told that the experimental archaeologist Bruce Bradley draws onto the core an outline of the flake he is about to remove, and then goes on to remove it. I outlined the shape of the point I was aiming for, thereby identifying the material needing to be removed.

Actualistic

I started using the pressure flaker to remove this excess material. However, the bump visible on the bottom left was proving problematic and so I tried the hard hammer. This resulted in what is called end-shock or hitting it at one point (the bump) and it breaking at another (in the middle). On the plus side I now had two more halves to work with. I continued with the left-hand piece.

Edge preparation

This is an example of good edge preparation. The ultimate aim here is to apply deep invasive flakes to the upper face. In preparation to do so I worked along the edge of the upper face removing short flakes and creating a steep edge angle. This provides a good platform angle to then apply the desired deep invasive flakes to the upper surface. This platform preparation process can be used to simultaneously shape the piece.

Stack

However, it is not as simple as it sounds. Here I ran into problems again where the angle didn’t work and I created a lump. Whilst not exactly at this point, it was with a couple of these problems that I left the piece last night. This morning I was able to re-address these issues more patiently. To do so I had to work back to the last point where I could get a good preparatory removal, and then edge along from there. When I could go no further I would move back a little along the edge and take a large deep invasive removal out. This effectively removes a lot of supporting material and provides a negative bulb that can again be worked. Complicated to explain, and I am learning on the job so to speak. Dealing with lumps like this involves losing width.

finished point

Anyway, the net result is good. This piece embodies a lot of my learning and working out. The really beautiful museum examples are perhaps so because the working out had been done a long time before, a working out that translates into bodily understanding. Consequently, on the museum examples we see confident and systematic flaking which leads to a clean and aesthetic conclusion.

The one point per day may be a little optimistic for me. With hindsight, if I was really being goal focused  I could have chosen an easier piece of glass and started the process earlier in the day. However, this glass is beautiful and I have taken time to negotiate a lot of issues that in the past would have been the end of the road. Furthermore, the first thing I did this morning was to get outside and continue with this piece. The deadline presents a focus upon an end product, and the learning process becomes a by product of the action. However a conscious focus upon the process is where the learning and understanding occurs. I have been reading about learning theory and this ‘making’ process is what David Kolb (1984: 30) has classed as Concrete Experience. As I sit now writing this blog I am reflecting upon this Concrete Experience and engaging in Kolb’s opposing category of Reflective Observation. Reflective Observation allows me to upgrade my understanding based upon the new experiential ‘data’ acquired through paying attention within the process. Doing so allows me to develop a new Abstract Conceptualisation or road map of what I need to do in order to make a Kimberley Point. With the next Kimberley Point I make I will be able to test out the usefulness of this new and upgraded Abstract Conceptual road map to see if it helps. The testing out process Kolb terms Active Experimentation. This brief four stage description isolates what is in fact a dynamic and blurred process of human action. However, the idea and practice of producing one new point per day provides a nice 24 hour learning unit within which this four stage process can occur, again and again. A further benefit is that it seems to get me out of bed in the morning!

Kolb, D.A., 1984. Experiential learning: Experience as the source of learning and development. New Jersey. Prentice-Hall Inc.

Hard earned

bone china 1

We have been having regular Tuesday and Thursday evening ‘knapp-ins’ for the past few weeks. Between the three of us we each gravitated towards different materials. Nick focused upon the remainder of the thick microwave turntable. Rob brought in some Langdale Tuff, a volcanic material with a fantastic texture, and I brought in a bone china plate. This bone china is hard, and very difficult to get long removals from. It really does seem to be a case of heavy abrasion to get incrementally longer removals, only to abraid again to get a bit further. Each of the above removals was hard earned.

bone china 2

Both Koalaboi and Nick recommended having a look at Paleomanjim’s Youtube channel. He uses a number of methods depending upon source material, but to maximise flake length he combined two approaches. Firstly he used abrasion and removals to create a steep angle that can be used optimally for one face only. He also used a pad with a channel cut into it. He has identified that having this void below the flake being removed means that it has absolutely no support, and thus comes off cleanly. Even small amounts of support (contact) can lead to step fracturing. This makes sense, although it doesn’t seem to be reflected in the Kimberley Points literature. Once optimal length flakes have been removed from one face, the the margin in prepared so as to remove optimum flakes from the second face. This process is primarily aimed at thinning and creating a lens like cross section. I have a couple of fragments of this material left, and so I am going to test out this steep platform method this Tuesday evening.

You need to be able to trust your platforms

platform 1

This post is about pressure flaking, what I am learning about the process, and how this learning is helping me to improve. The main learning outcome currently is summarised above: you need to be able to trust your platforms. So what does this mean in practice? To explain, it is useful to reiterate my own understanding of what constitutes a platform from a previous post (An interesting learning experience):

Primarily,  I identify the area of the fragment that needs reduction. I then focus in to find bits that stick out. These points will be inherently weaker due to the lack of support on both sides. Consequently these points provide useful platforms with which to remove invasive flakes. If this platform sits above the centre-line of the edge I will flip the flake over and use it to remove a flake from the dorsal surface, if it sits below then I will use it to attack the ventral“.

So fundamentally I am identifying an inherently weaker area to target with the aim of thinning the piece. The platform is simply the area to be pushed into with the point of the pressure flaker. Heavy abrasion of the margin effectively removes any weak areas and establishes a strong platform. This seems tautologous in that I am identifying a weaker area to exploit, only to then strengthen it. However, it needs to be strong enough for me to apply pressure effectively in order to achieve the aim of removing a flake. Failure to prepare the platform can lead to crushing of weaker zones when the pressure is applied. This acts as a shock absorber dissipating the energy being applied and compromising the flake production process. I am therefore learning that the issue is not me becoming stronger, but applying my strength more accurately and cleanly into a prepared area of structural weakness. The connection between the pressure flaker point and the platform needs to complement the angle through which the pressure is to be applied. So far so good.

However, how I began to understand this is of interest. I am currently using glass and aiming to ‘push’ flakes across to the centreline of the artefact. An inhibitor to pushing into the margin with real strength is the possibility of the pressure flaker slipping and shards of broken glass being pushed into your thumb. This second possible outcome inhibits the confident application of as much pressure as possible into the platform. Conversely, the recognition of a constellation of factors under my control: recognising an area of overall structural weakness; preparing a strong platform; using a sharp pressure flaker; understanding the required angle; all of these control opportunities are giving me confidence that I will now achieve the former, rather than the latter, outcome. This confidence is now allowing me to really apply pressure and begin to push off longer flakes. The above understanding of how to make it work is giving me confidence to push in hard, and to make it work. A virtuous cycle is emerging. I already had these conceptual knowledge components, but I realised today that my bodily confidence has increased along with the knowledge that my platforms (through preparation) will behave predictably under increasing pressure. I am learning to trust my platforms.

pressure flaking