Some disciplined pressure flaking

I survived the Archaeology and Classics Ball. And the rock club. And the Chinese meal. And woke up at 9am this morning feeling surprisingly OK. The sun is shining today and so I spent the morning making a second point to send to Australia. I am still finding it fascinating to reflect upon how I learn. There was a temptation right at the start to use my dog chew antler hammer to thin this bottle base. I am developing a way of working that is becoming automatic, and that is actually counter-productive. Counter-productive in that I am trying to follow a prescribed method, rather than simply do what I do. Perhaps it was at this point of recognition and because I am following his method, that I unconsciously had in mind Kim Akerman’s ‘Roseleaf‘ point. I think this may be the case as it is ultimately what I ended up with.

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Anyway, in relation to the title of the post, I used systematic pressure flaking to reduce one face and then the second. The bottle base was thick and flat and I didn’t lose much width which is a result. The above flakes were removed by pressure and they are useful. I was told last week that an artefact had been pressure flaked. It hadn’t and both Nick Overton and myself could tell by the wide removals that it had been thinned using a soft hammer. Pressure flaking seems to have taken on an occult aura, something special. In many ways it is, but perhaps no more so than skilled hard hammer work, or soft antler hammer thinning. However, familiarity with these processes, and the resultant scar patterns and debitage has now been absorbed into my understanding, and I don’t remember making myself do that. It has just happened through engagement.

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A little of the lettering from the base is still on it and I like that. Note the serrated edges as well. I produced them differently this time after having a good look at Kim Akerman’s example.

11b. Final form Convex face.

Now I have had another look at Kim’s I am a bit less pleased with mine! However, mine is technologically correct, made from period material and will soon be winging its way to Australia. Whilst not perfect, I think I would be pleased to receive it through the post.

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Mancunian exotica

As is usual here in Manchester, the weather has been absolutely fantastic. Consequently I have been outdoors a lot and the dog and myself spent an hour or so having a root around Chorlton Ees. I am still amazed at the amount of treasure there is to find just lying on the surface.

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Some material has been unearthed by burrowing animals, and some has just been lying around for many decades. I was particularly pleased coming home with a carrier bag full of 1900s thick broken bottle bases. This glut of material reminded me that I am indebted to three people and I have not made any effort yet to repay their kindness. It would seem that now is the time.

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This Kimberley point, or more accurately Mancunian point is made from the flat piece of glass on the left. A scratch on the surface caused a little step fracturing but ultimately it was no problem.

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I am really loving flint knapping at the moment and I have lots of material to play with. The sun coming out is just the icing on the cake and if it stays like this I can look forward to getting the other two done in the next day or so. In the meantime I will enjoy posting this one off tomorrow morning.

 

 

Guest post by Sunny Lum on his first experience of glass knapping

In October last year I attended John’s experimental workshop for creating Kimberley Points. As a complete novice knapper, I only had a vague idea of what would be involved, and had only prepared myself by watching a couple of quick flint knapping tutorials on Youtube beforehand, although these turned out to be almost completely irrelevant to what we ended up doing! At the start, John introduced us to what Kimberley points were and we had a short talk about the origins, uses and evolution of their creation, and also discussed the overall aim of the workshop, which was to try to end up with our own points after about 4 hours of work. He also showed us the tools the Australian aborigines originally used, namely a piece of number 8 wire, which was commonly used by the Australian sheep farming community to fence in their sheep. He also introduced us to our tools which we’d be using, which he’d created himself, adapting the wire by adding a wooden birch handle to allow better control. Other necessary equipment; huge tarpaulin to cover the floor and collect up all the glass shards, glass bottle blanks (rough cut to manageable size), a section of deep pile carpet (to protect our legs from self-inflicted damage) which was very thoughtful, protective goggles / glasses (plus coffee and plasters!)

Glass, plasters and coffee
Then there was the introduction to the process we would be using to create these points. This was explained very clearly through the use of a series of diagrams drawn onto the whiteboard, showing 2 distinct methods that created 2 different effects.
Sunny ignoring the view
The first step was to create a platform, which involved applying pressure with the wire almost orthogonal to the glass shard then changing the angle to create a pressure point, which breaks off a piece of the glass at an angle. This technique was used to create an angled platform on the side of the glass, which is used for the next step. Additionally, this step also is used to shape the glass into the correct shape.

Sunny, Rob and Rob

The second step was to use the platform created to apply pressure along the breadth of the glass shard in order to thin the edges. The process then repeats itself until you have reached the desired shape and thickness. John demonstrated the technique for the first step, and we tried to replicate it. It took about 50 mins or so before I became comfortable in creating a platform consistently. This was down to several factors; time to develop a feel for the correct angle and pressure required both to apply to the glass and also to hold the glass and tool in place to exert it, time to develop trust in the carpet to protect me from stabbing myself in the thigh, time to understand and get a feel for how the glass samples behaved when pressure flaking them.
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As part of this process, you had to adapt to the edges and shape of the glass. Depending on which way the edge slanted it was easier to create the platform from one side or from the other. This resulted in distinctive fracture patterns in the glass which was easily readable by John when he came to examine our handiwork. Once we had 2-3 blanks roughly platformed, John then demonstrated the second step to thin the edges. The technique was in essence the same as the first step, difference being the angle is now along the width of the glass instead of in step 1 where it was through the depth. This creates flaking across the width of the shard and removes material in order to thin the edge.

Sunny and his steep retouch

This similarity of technique allowed us to jump straight into step 2 quite quickly, although again it took time to develop a good feel for the amount of pressure required, angling of the tool and glass and again familiarisation with the fracture qualities of the glass in this different plane. We used some more modern glass and also some older turn of the century glass, which better replicated the aboriginal raw materials. This was particularly useful as it showed the difference in fracture characteristics. Modern glass was easier to create the platform, but was harder to thin, the older glass was harder to create the platform, but was easier to thin.

Rob Howarth and Rob Fulton

This phase was quite tricky because the process of thinning the edges destroys part of the platform, so if you didn’t create enough material removal from across the width of the shard to thin it, you ended up with a broken platform which was hard to re-use without resorting to step 1 again. It took some experience to realise this and frustrated progress when you really should have moved on. Rob Howarth, who had more experience knapping, ended up producing a pretty impressively shaped and thinned piece at the end, going through the two steps multiple times.

Rob Howarth's slim point

Time passed very quickly, and I enjoyed the challenge of working out how and where to apply the pressure to flake off and shape the glass. It helped immensely to have a file at hand to resharpen the points on the wire tool. The blunt end dissipates the force, requiring you to exert more and results in less controlled fracturing.
The biggest challenges I faced:
* developing a feel for how to hold the glass securely and safely
* developing a feel for how to apply the pressure into the glass securely and safely
* developing a feel for the angle and pressure required to create the pressure flake for step 1
* developing a feel for the angle and position and pressure required to create the thinning for step 2
In the end, I ended up with 3 half finished pieces. I was a little disappointed that I didn’t have a finished piece, however I was very happy with the progress I’d made and the skills acquired that I could continue to work on those pieces if I wanted to. Overall, a very good well run and guided workshop. Helpful if you have some prior experience, but not necessary. 

Sunny smiling, Rob F inspecting
Many thanks to Rob Fulton for being one of the guinea pigs, Rob Howarth for providing the cleaned period glass and these photographs, and Sunny Lum taking the time to put his reflections down on paper for me.

Kim Akerman makes a Kimberley point

I have mentioned a few times that Kim Akerman is the preeminent scholar when it comes to these points, and that he has been very helpful in my research. He has kept in touch and answered some of my questions on the production process that have been sticking points for me. This post is his response to a couple of my general questions, about the correct order of work, and invasive flaking without losing too much width. To illustrate he produced a point and recorded the process. This post will be lengthy, but informative if this is a subject of interest. This body text is my interpretation, the photos with text are his explanations.

 

 

This is the piece of water worn period glass that Kim started with. We had discussed the differing ways of establishing a platform and this was the issue he dealt with first of all.

 

 

He used the margin of the convex outer surface as a natural platform and a small hard hammer along one edge, and a pressure flaker along the second to begin invasive flaking. As can be seen both methods achieved similar results.

 

 

He then continued to take more invasive flakes and establish in his mind the shape of the point he was aiming for. All this flaking was aimed at flattening the inner concave surface of the glass.

 

 

Here we can see that whilst the inner concave face is now heavily worked and being flattened, the outer convex face is as yet un-flaked. Shaping in plan has also begun.

 

 

5c. Lateral edge showing unifacial pressure flaking on interior concave faceSame story in that the concave inner surface is now almost completely flaked apart from an intermittent central ridge of original surface. Kim has a problem with this later. The curved outer surface still remains un-flaked and you can see the edge of the original outer glass surface curving up at the forefront of the photo.

 

 

And at this point flaking of the easier convex outer surface begins. What follows is a process of flaking and shaping to achieve the approximate form required.

 

 

At the above stage the easier to flake curved outer surface is used only to create platforms so that invasive flakes can be removed from (what was) the curved inner surface. The aim here was to remove the intermittent central ridge of original surface that remained on the inner face.

9b. Removal of margin by overshot flake

The aim was to get flakes to penetrate across the centre in order to remove the problematic ridge and it is at this stage that a flake overshoots and takes off too much material.

 

 

the central ridge has been removed and the task now is to bring the reduced piece back into shape, and this is done by working both faces.

11a. Final form. Concave face

11b. Final form Convex face.

This is the end result, what Kim calls a rose-leaf shaped point. I commented in the previous post how my points need to be called ‘Manchester’ points. I think this is not the case for Kim’s. He was trained by aboriginals, uses the same bodily methods, materials, tools and reduction sequences. When aboriginal tool making lapsed, Kim carried the process on, and I believe this is why he has gone to the trouble of sharing the process here. He cares about sharing this knowledge with other people who value it. Perhaps the process of sharing a valued knowledge was one part of what Kimberley points were about.

Thoughts on Kimberley Points, teaching and learning

Last Saturday afternoon I spent four and a half hours with Rob Fulton, Rob Howarth and Sunny Lum testing out a Kimberley Point workshop idea. Rob Howarth is pretty experienced in that we tend to meet up most weeks to knap. Rob Fulton and Sunny Lum however were knapping novices, and as such, ideal for my experiment. I wanted to see if I could lead a novice knapper through the process of producing a Kimberley Point in one session. Spoiler alert: I couldn’t.

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I had used a glass cutter and hard hammer to make some preforms from the old plate glass that we have. Rob Howarth works at the University of Salford Centre for Applied Archaeology and had kindly contributed some samples of 20th Century industrial plate glass for us to use. There are real qualitative differences between differing glass types, and one of Rob H’s samples in particular was excellent to work. By using these samples I tried to make the preforms formally (shape) and materially (type of glass) conducive to working into Kimberley Points. I also had outlined a clear and idealised reduction sequence.

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Having introduced them to the rich and interesting background to the points we started on the preforms. I had realised when putting together the idealised reduction sequence that they needed to grasp two basic types of retouch: steep; and deep invasive. We started with steep, and it took a while. I had underestimated how long it takes to get a feel for a new process, and for Rob F and Sunny it was a very new process. The first hour and a half perhaps was taken up with producing steep retouch on a series of blanks. Ultimately, Sunny got it but Rob F was unable to consistently apply it. This was frustrating for both of us and obviously had implications for the next phase, because the steep retouch was in fact producing the necessary platforms for applying the deep retouch. Rob Howarth was able to produce a number of steep edged blanks ready for the next phase, and perhaps this emphasised the value of previous experience.

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By moving on I was hoping to allow them to experience the practical value of the good platforms they had produced through steep retouch. The experience of using the platforms would perhaps provide them with a different understanding that could be used to refine their process. Sunny picked this up pretty well and was able to concentrate on increasing the depth of his flaking. Rob H produced a fully surface flaked example, the best he has yet made. I think for Rob H the clearly outlined reduction sequence was really helpful as it allowed him to apply the skills he had already developed in a structured way. For Rob F it was more difficult. I was able to clean up his edges so that he had good platforms but his ability to get deep removals consistently was the problem. Some worked really well and some didn’t at all and this became increasingly frustrating. I know this feeling well and I found it difficult to help. We worked closely together, but a transition gradually occurred, leading ultimately to me doing most of Rob F’s retouch. He had run out of steam. This experience has reiterated to me the value of the glass bottle arrowhead workshop as an introductory tool. He would have fared much better with that one, but this session was more like the ‘deep end’ so to speak.

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Rob H ran into problems with the later phases of my idealised reduction sequence, mainly losing width with each subsequent round of steep retouch and invasive reduction. Consequently his beautifully surface flaked blank was becoming narrower but remaining relatively thick. This has to be to do with the angle of the invasive removals. As I said earlier, Rob H, Nick Overton and myself sit down together most weeks to knap. I think we each have a slightly different style and approach, and indeed Sunny commented on the differences between my own and Rob H’s physical approach in this session. I think Rob H’s flaking style is more similar to Nick’s than my own in that it is more invasive but shallower. This results in less thickness reduction. My flaking is not ideal but I think I aim for a steeper angle of removal to reduce depth. This is the punchy retouch I have discussed elsewhere. This is something for myself and Rob H to work on in our Thursday sessions.

So conclusions. I couldn’t help but feel a little disappointed at the end. Rob F was kind enough to volunteer and it turned out to be a frustrating experience for him. Rob H produced his best surface flaking yet, but depth reduction has emerged as the next key phase to get on top off. Sunny seemed to enjoy it and got the processes. I have worked with Sunny a lot in other contexts and I know he is an efficient learner (and good teacher). He was also happy to go away with the conceptual outcome of understanding and also being able to practice steep and invasive retouch. Rob F had to get home for babysitting and the remaining three of us worked through Kolb’s reflective phase in the pub afterwards. I have since had a week to digest what went on. I actually really enjoyed the day, working together to develop skills and solve problems. I have also gained a new appreciation for the complexities underlying apparently simple tasks such as applying steep retouch. I now think there is almost a (very un-sexy) session on simply applying retouch, perhaps linking it platform preparation, and the platform categorisation systems that are used in archaeological analysis (linear, punctiform, etc.). I like the idea of workshop participants going away with something they have produced. Rob H seems to be the same in that each of his artefacts has a story behind it: where and when it was produced; the material it is made from; the issues it raised. The artefact contains the story which contains the experience. I realise for me that these blog posts are becoming the more tangible outcomes of my ideas and experiences. Sunny seems to be content to go away with a grasp of the experiential and conceptual understanding. Rob F is going to give me some written feedback, and Sunny is going to produce a ‘guest post’, and Rob H too if he is up for it. But let me here thank all three of them for giving me the time and providing me with some real food for thought. The photos used in this post are all Sunny’s.

 

On quartering a glass bottle using a stone (again)

I had an enjoyable knapping session with Nick Overton this week and it has been a while since both of us sat down together. I want to organise a Kimberley Point workshop, and so my theme for the evening was to consciously work through the production process. My aim was to grasp what is practical to work through in a three hours session with a potentially new knapper. I started with a green glass bottle base and side panel from the usual source. The first step was to separate the side panel from the base.

To do so I used a length of no.8 wire to attack the inner junction of the basal section and the side of the bottle. It worked pretty well in that it took out three big sections weakening the overall integrity of the bottle. So far so good. There is absolutely an auditory component to this process and that is something I am going to explore in more detail. After the third removal the increasing thickness of the remaining glass meant that the base snapped off, taking with it a section of the side panel. The break followed a path of least resistance (and thickness) and left me with a base and curved side panel.

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I then flipped the side panel over with the dorsal (convex) surface uppermost in order to produce my blank. I used the hard hammer to produce a line of weakness and this again had aural and visual clues as to how well it was working. When I had the required line I flipped it over to expose the inner (concave) surface and struck the inside of the same line once. As you can see, it worked pretty well.

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On the close up below it is possible to see the hard hammer impact marks. The no.8 wire tool used to remove the base is in the background.

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I then proceeded to do the same thing on the other side, but with less success as it split into four pieces.

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This process is intriguing and I need more practice to get consistent results. Consequently I will probably discuss this process, but start other people off with preforms.

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Above is the resulting point from the lower section of the side panel, and below is the aboriginal example from the Manchester Museum.

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The main difference is flatness. Mine is lens shaped whilst the museum example is plano-convex, and a little more refined. The difference is subtle and qualitative, but I think boils down to the length of the removals and resultant edge angle. I am able to systematically produce points and the main areas for my own improvement are: getting longer removals; systematic hard hammer quartering. In relation to the workshop idea, I think if we use preforms then I can probably lead someone through the process in three hours.

Another one headed for the backyard

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It took me a long time to get this wrong. The glass was tough and it wore out one complete nail on my pressure flaker. However the problem was me and my angle management. It is narrow because I persisted but rather than getting flatter deeper flakes they became steeper. I don’t like it and it is headed for the box in the back yard. I am not sure what I have learned from this one, although it is the second on the trot where my thinning has been inadequate. Perhaps I have learned that I need to improve my flat invasive flaking.