New Season of shows – Yandles Spring show

First demonstration of the year at Yandles Spring show this Friday and Saturday. I am amazed at how far I have come, this show last year was the first time I had forged an axe in front of a crowd, it took the entire day,  hopefully we should be a bit more fluent this weekend! I have made a few tweaks that should help things along further:

New season preparations 1

 

Firstly I have been trialling a different sledge hammer design, virtually everyone that has used my larger sledges has ended up with bruised hands, it puzzled me at first as I have never encountered bruising when using single handed hammers. Working by myself I have had very little experience with sledges; eventually it struck me that mostly my strikers were holding the sledge with their hands far apart:

New season preparations 2

This is understandable, the hammer is heavy and there is more control and accuracy when holding like this; however when a (single)  hand hammer rebounds the head goes up but the centre of rotation is in the palm of the hand so little shock is transmitted to the hand through the handle. With the hold shown above the the centre of rotation is between both hands, so when the head rebounds the hand nearest the head receives a big shock from the handle in the web between thumb and forefinger.   The back hand doesn’t suffer in the same way as the handle is moving away from the hand at this point.  New season preparations 3

If you look at the new sledge, the handle is so short that it feels more natural to have both hands together, the centre of rotation is between both hands, but as they are so close to this point the shock is reduced to almost nothing. It looks odd but has worked well in the workshop. However I think it will look a bit like a toy in the hands of Rob, my regular striker at shows, I will find out his verdict in a couple of days!  This is of course a compromise, the bigger sledges will hit harder but really need to be held with hands together to reduce the shock, with practice this is possible but it is difficult to do this accurately, when I am teaching courses the shorter style of hammer looks to be the way forward.

The second thing I have done is to reduce the height of my anvil block, in the workshop during courses I have been putting a pallet down but  it seemed sensible to have a dedicated axe forging block. I moved both of the steel bands down and we marked out for the cut. The Oak had many splits in it that had filled with  forge scale over the last decade, the chainsaw was blunted in seconds but we eventually managed to cut around 4″ off it.  I used a  chisel I made around 15 years ago to bevel the edges on the block; the edge held very well considering the rough time it had. This set me thinking, with the knowledge I have now all the heat treatment was wrong; the blade was laminated but I didn’t follow the rigorous thermal cycling I now use to relax the steel after the stresses of forgewelding, I quenched at the wrong temperature, too cool, although this was judged by eye, the quench medium was wrong, water  rather than oil and finally I tempered at the wrong temperature 100 degrees centigrade, boilling water. I have heard it stated that this steel should be tempered at 250c  when used on wood.

Yet despite all this the edge holds up well; this wasn’t all  just accident I had found by trail and error that this recipe worked . What I think happened was this: As I was relatively inexperienced at forging I finished the blade relatively tentatively at a series of low heats, this mimicked the thermal cycling that I now do. I had the hardening temperature too low, but quenching in water gives a more aggressive quench so this sort of balanced out, if I had quenched in water at the correct temperature the blade would have cracked or at  least warped. The resulting quench didn’t give a very hard blade so lower tempering temperature was needed. I would still do things differently now but you can learn a lot more from trial and error, I would recommend this route rather than reading up obsessively on Heat Treatment.

Just after taking this photo I was asked to run a course making spoon blades with handtools and no complicated heat treatment, not my usual thing but I made one as a test piece; this was the result, everything done by eye or hand and I managed to replicate the edge geometry that I find so important in my production blades. It was a pleasant experience, filing and forging is much more rewarding than grinding.

Filed blade 2

 

Testing Grain Orientation

Which is the best way to orient the grain?

Which is the best way to orient the grain?

 

In my last blog post I wrote about grain orientation in carving axe handles, making the assumption that having the rings running parallel to the bit of an axe (1) would be stronger, however speaking to Lee Stoffer about this in December sowed seeds of doubt in my mind. I found lots of research on the effect of sloping grain on timber ( when the grain is not parallel to the to the cut timber) . A figure that stuck with me was that a 10 deg slope reduces shock resistance by 50%. I measured the slope on some handles I had rejected and found a slope of 20 deg. The most applicable research related to baseball bats, this paper suggested that grain orientation makes no difference to strength in non sloping grain. However there was a statistically significant difference when slope of grain was added into the equation. Interestingly the stronger orientation in ash was different to that found in birch and maple. Unfortunately no figures were given. However this research suggests a 25 degree slope of grain would reduce strength by 60-80% ( I am fudging here, toughness, modulus, compression, shock resistance were all measured, giving for a very confusing graph)
The plan was to test some sections at 25deg slope, very much a worst case scenario. the sections would then be tested in both grain orientation. I cut slices 1cm thick from two pieces of ash from my woodpile one with approximately 12 rings per inch/ 25mm and a second with 6 rings per inch. The slices would then be cut to make 1cm x 1cm cross sections. Some 1cm square non sloping sections were also cut to give a baseline measurement.

grain test1

The plan was to compare the strength of these different sections, I was going to support the sections a set distance apart on my digital scales, then slowly press down on the centre of the section and record the maximum weight recorded before the section broke.

grain test 3

Unfortunately the scales bottomed out at 30kg, and at this weight the sections all held. I put them on my belt sander and reduced the section to around 6mm. This thickness meant that most of the samples tested from the slower grown ash broke at around 15kg.
I have struggled how to describe this grain orientation, radially/ Tangentially, Vertical/ Horizontal? Edge and face loading was used in the baseball bat research. In terms of axe handles I think annual rings parallel to the bit of the axe – (1) or perpendicular (2) work well but again a  picture is clearer:

2 and 1numbers added

 

Results:

Put simply, taking 100% to be the non sloping baseline tests.

In slower grown ash: Orientation 1 gave 98% strength, and 2 gave 89%

In fast grown ash: Orientation 1 gave 41% , 2 gave 27%

However the fast grown was almost exactly twice as strong in the baseline tests. So the figures aren’t quite as far apart as at first sight.
The difference is significant though , also the sloping grain samples broke with virtually no warning in the fast grown ash, whereas there was noticeable bending and creaking in the slower grown samples. At 25 degrees slope a handle would have been stronger if made from  the slower grown ash, however as the angle decreases then the point will come that fast grown ash in orientation 1 will be stronger. In a straighter handle the fast grown ash will be stronger in either orientation.The increased strength in orientation 1 also ties in with the baseball bat research I came across.

These results ( see provisos at the end) are interesting, in a curved handle if I can’t use any natural curve in the grain to my advantage then I will be using fast grown ash with the annular rings parallel to the bit of the axe (1) If I wanted a really curved handle and had to make it out of straight grained ash I would choose slow grown ash over fast grown, a chain being only as strong as its weakest link.
Provisos

This was only meant to be a light hearted test done over the Christmas break, my children helped break the sections . However my training was in similar sorts of research and I am very much aware that the sample size of this test (24) is too small. I hope to continue with the tests to see how repeatable these results are, in the meantime other related issues include:
1.  I have included odd spikes in the data to get averages, these should have been ironed out with a larger data set.
2. It is also very difficult to start with a grain aligned at 0 deg, the slower grown wood had definite twist in it. Again this error should be reduced with a larger sample size.
3. The fast grown ash actually bottomed out the 30kg limit on my scales on half of the aligned samples, I estimated breaking force in these cases.
4. I am not certain that the results from the small sections that I have been testing can be extrapolated to axe handle dimensions, instinctively I would say yes, but at any rate the sections used are not that far off spoon dimensions, which may well be of interest to a wider section of readers.
5 Lastly, is breaking weight/ force a good test to replicate failure in an axe handle? probably the Izod impact test would have been better but beyond me or my young assistants.

Axe handles part 2 – geometry

In the last post I explained my reasoning behind the various ways that the grain can be oriented in an axe handle. However if the handle is straight then it makes no difference and any of the methods I described would work, you could even steam some curved branch wood straight if you really fancied a challenge.

Making axe handles

Aesthetically I prefer a curved axe handle, however when you choke up on a curved handle it also brings your hand closer to the blade, effectively reducing the poll to edge measurement of the axe. I have found that axes with shorter edge to polls to be more accurate and easier to use.  (3) shows this effect well, the curve puts the handle way below the centre line that a straight handle with the same basic geometry would have (1)
The main factor concerning handle shape is the eye orientation in the head. A handle in a carving axe works best for me when it points out roughly horizontally or slightly upwards ( handle pointing upwards is described as open) – this is the my major concern when laying out a handle. (1)
When forging an axe head I tend to orient the eye so it points slightly downwards towards the beard, meaning that a curved handle is needed to accommodate this overriding geometry. A  head that has the eye in line with the edge will need a straighter handle. (2) shows a head that would I think be better off with a straight handle, as it is it has been fitted with a handle that curves the other way, making it point downwards. This type of handle orientation sometimes described as closed.
I prefer a shorter axe handles but like the counterweight effect that a longer handle gives, leaving an oversized bulb to help with the balance, French Clog makers axes take this to extremes. The idea of lead loading to really try and play with the balance point  without resorting to massive bulbs is something I have intended to play with for a few years now.
Hybrid axe handles
I have been testing out this axe I forged recently,  all the roughed out ash handles in the last two posts were carved with it. Although it works well the handle isn’t quite right, I think it needs to be more open.   As I can’t easily alter the eye geometry I am putting more curve in the new handles to achieve this. Of the two roughed out for testing, one basically follows my standard design, the other is a nod to the bulbous French clog axes I mentioned earlier. These are now dry and ready to test, so there will be another instalment when I have some firm opinions on how they are working.

Handles, Helves, Hafts: call them what you will.

I have recently been fitting more handles on my axes. An accountant would recommend that I cut them out on the band saw and then rip them into shape on my belt sander. But I enjoy carving them by hand and it allows me to try out my tools, and although slow the process is much more productive than just making shavings which I sometimes end up doing when testing.
I like curved handles aesthetically and tend to forge axes that need curved handles, it seems a shame to forge a flowing axe design then put a broomstick of a handle on it. However as I will explain in the next post there are times when straighter is more suitable.
Carved axe handles

Axe handles

 

If you are going to make a curved handle then the issue of grain orientation is going to come up. The most elegant solution is to find a branch that perfectly matches the curve of your intended handle (1).  No short grain, but the ones I have made in Hazel have been a nightmare to carve as the grain reverses in really unexpected places. It is pleasing though to be able to place the pith dead centre in the both ends of a handle.
I have, however not got easy access to much woodland and have already cropped most of the likely looking branches, single curves are easy to find (2) but finding the perfect double bend for my preferred handle shape is not an easy order,  not to mention the horror of finding the rotted remnants of a knot at the apex of one of these all important bends.
So, a nice idea, and viable if you are only looking to do a few, but no longer my preferred method.
Another intriguing way of guarding against short grain is to steam bend straight grained wood, not something I have tried, and although it seems easy enough to get a single curve, my preferred form would, I think be tricky.
For the past year or so my approach to the issue of short grain in largely straight grained wood ( I have been splitting billets out of larger logs of ash and elm) has been to try and minimise it by lining up any curve in the grain with the curve in the handle as best I could and accept that there will be shorter grain in some sections (3), I have yet to have a handle start to split let alone fail on me. However as I have been tending towards more extreme curves it has been apparent that I am going to be limited by the short grain.
At spoonfest last year I watched Jarrod carving a spoon blank from radially split wood and realised that this is a much better solution. So I have roughed out a few and it seems to be the answer,  the short grain issue is reduced and the profile seems easier to carve as well. (4) have yet to try these out but I forsee no problems.  However to use the wood I have efficiently I expect that I will use both orientations of grain, using my original grain orientation on the straighter handles.
I always carve my handles in two stages, I rough them out when green , leaving them oversize to allow for shrinkage or possibly bowing – this seems to happen more often in curved branch wood blanks than from straight grained wood. When I am sure they are dry I will rough fit the head, making sure I am happy with the handle orientation as it goes on. Then with an axe I will hew down as close as I can get to the finished size. Next I with a knife I will clean the faces, the bulb on the end and put on the facets, this can be tough going in seasoned ash.  I have now settled on 12 sided handles, still crisp facets but not so defined that the corners feels sharp.
Next I will saw a slot and make a wedge from Oak, I am not overly concerned about the Oak being kiln dry; I leave my wedges long and expect to be able to tap them in or pull them out if I want to take the head off. A couple of coats of Linseed oil and it is ready to use.

 

Tyntesfield Tool Making 2 – The course.

The course went well. We had two forges, two anvils and six students, I decided that we would have Dave and Tom making axes using the coke forge, and Dick, Angus, Mark and Peter making adzes on the gas forge, it sounds unfair but as the gas forge holds the steel at a constant temperature it is possible to have more than one adze being heated at once, in the workshop I will typically run three blanks in the gas forge, this way as soon as I have finished forging one blank I can pull another one out and immediately start on that, there is no down time waiting for a piece to come up to heat, having many irons in the fire. At Tyntesfied we ran one axe in the coke fire against two adzes in the gas forge.

I broke the process down into stages and demonstrated with Rob striking for me. Next, everyone paired up and would forge to the same stage, then the director and striker would swap places. This way everyone got to experience every process, and if all went well I wouldn’t have to take over at any stage.

Although the starting stages of making an axe and adze are identical they obviously diverge at some point and generally Rob looked after Dave and Tom on the axes and I concentrated on the other two pairs on the adzes. I took some photos but they were totally eclipsed by this set that Peter took.

adze blanks

Scoring an adze blank so the slitting set would locate accurately in the centre.

Axe blank being slit with the new set

Axe blank being slit with the new set

adze split

Adze completely slit, the bolster allows the set to go all the way through without driving the sharp edge into the face of the anvil.

Rob looking after the axe boys.

Rob looking after the axe boys.

adze part forged

Adzes part forged, nice and even eyes which makes everything so much easier throughout the whole forging process

forging

Forging out the lugs on the eye of an adze between top and bottom fullers, the drift is inserted into the eye other wise it would be squashed flat. Tne handle is about to come out if the fuller, a more wedges needed obviously.

Spreading the blade out on an adze with a handled fuller.

Spreading the blade out on an adze with a handled fuller.

Adzes heating in the gas forge.

Adzes heating in the gas forge.

Quenching ( hardening) in oil.

Quenching ( hardening) in oil.

 

Adzes showing temper colours and ready for the final grind.

Adzes showing temper colours and ready for the final grind.

Finished

Finished

Although I did help out at a few stages some of the adzes were completely untouched by me, so brilliant efforts all round, it was quite an effort to transplant all the equipment needed to a Marquee 170 miles away but the results, as you can see were definitely worth it.

Tyntesfield Tool Making 1 – Preparations.

I spent the best part of a week getting ready for an axe and adze making workshop I was running ar Tyntesfield for the Sommerset Bodgers. Originally I was asked just to make axes,  however some pictures I posted recently of adzes made on a course at my workshop had over half the participants jumping ship and wanting to make adzes. In a way this is more difficult as I need to teach making two different tools rather than one, but then with Rob along to help out it won’t be so difficult to split the group. Adzes are quicker to forge, but take longer to do the final finishing which may help to spread the load, or, if I don’t get timings right make for a big crush to get to the grinder. One thing is certain though, as I already have one set of tools for making axes and one for making adzes I needed to make less extra tooling up for the course. There are going to be 6 participants so I will need multiple sets, luckily not six, as everyone will pair up taking it in turns to strike for their partner.

 

blacksmith tools

Firstly the starting point.

From the left:

1. A section of  EN9 Tool steel that I will make a fuller for, this will be for spreading the steel in one direction to shape it, the action is similar to that of a rolling pin on pastry.

2. A chisel that was hurriedly rolled up to make into a gouge at a show, this needs flattening and resharpening as it will be needed for marking the steel stock prior to slitting it.

3. A Large sledge hammer head that I want to reshape, in axe forging a find weight is really important, especially as I tend to use heavy drifts, a light hammer really struggles with these.

4. a section of silver( tool) steel that I will make a slitting tool with, this isn’t really thick enough and will be upset under my power hammer to increase the section width around the eye.

5. An axe eye drift that has suffered over the summer show season, just needs reshaping and smoothing.

6. Adze eye drift that needs similar work.

7. A section of mild steel that I will use to make a couple of pairs of tongs up with.

8 and 9  A section of  EN9 Tool steel that I will use to make a fuller tool that will fit in the anvil that is available at Tyntsefield. The section next to it is a failled axe head in mild steel, this will be the section that fits in the hardy ( square ) hole of the anvil.

 

blacksmith tools

I started with the tool steels that needed forging first, I was in a real hurry and kept telling myself not to dwell on aesthetic beauty in these tools. as it was they turned out even and went quickly, but in forge work this often goes hand in hand. from the left:

1. The marking chisel

2. The silver steel slitting sett.

3. EN9 fuller top tool

4. En9 Fuller bottom ( anvil ) tool.

Blacksmith tools

Then on to the tongs- these were a joy to forge, mild steel is so much easier to forge than tool steels, especially by hand, and tongs do need a fair amount of hand forging, although a lot of the heavy work can be done under the power hammer. In woodworking terms you could compare the tongs to fresh birch, the tool steels to seasoned ash.

1. These will be used for gripping inside the eye of an axe or adze.

2. A pair that can be used to grip rectangular or square section steel. These work best over quite a narrow size range so I have lots of tongs in different sizes, these are going to be sized to hold the steel bar that the adzes will be forged from.

 

Blacksmith tools

And the finished set.

1.

2. Drifts were easily smoothed out.

3. Fuller  (bottom) tool fitted to my anvil, will be a loose fit in the Tyntesfield anvil  ( a few wraps of duct tape cures many problems and this will not be an exception)

4. Chisel – has been heat treated and sharpened now.

5. Hammer – With a very rough handle fitted, despite saying that weight was important I decided that this could afford to lose a pound or so as it was nearly 7 pounds, made sense not to forge the pein on in this instance as the goal was to lose weight not preserve it. Cut away with an angle grinder and shaped on the linisher.

6. Fuller tool- this has a very small radius and will shape the steel quickly, these are not swung but struck with a sledge hammer, so the handles can be even cruder than the hammer.

7. Slitting tool, similar useage so similar handle, I had been told that you should leave the heads loose on tools like this to reduce the chance of breaking the handles, but after spending the summer continuously correcting wobbling heads I decided to fit them more securely, not a great loss if the handles do break.

8. Tongs for holding an axe or adze securely from the poll, allows the blade to be inline with the tongs which makes it easier to keep things straight and balanced.

9. Tongs for holding adze stock these will either hold across the flats of the bar, but as I have forged the jaws into a right angle section they will hold much more securely if rotated 45 deg to hold across the corners.

And that is hopefully all the extra tooling I will need for the course, its not finished to the level of my usual work, but I am happy that they will do what I need them to.

 

Update

Spent some time today trying out the new tooling, also got the blanks for the course forged to size under the power hammer. From the left-
1. My new favourite hammer! Is a nice weight to use, 6lb with the handle. Cross pein prooved to be very useful.
2 Tidied up the last axe I forged this summer at the European Woodworking Show, guest striker was Joe, Anna Casserley’s partner, was complaining of being bored so Rob gallantly stepped aside.
3. Adze stock, still needs to be cut into sections.
4. Axe stock
5. Axe I forged,  trying out some of the new tools, and a new blank shape.
6.  New blank shape, was testing this size out, makes for a very wide eye so will make the handle fit very solid, but on balance it was too wide and thin, unnecessarily difficult to forge, not a section I will be using on the course this weekend.
7, 8, 9 Last year I made all my axes at shows from a large piece of tool steel. Next year I hope to be making them from Mild steel with a section of tool steel laminated in,  this is technically more difficult to do, but the forging will take less force as mild steel is much easier to work.  Expect these to take the same amount of time but should make for a more impressive demonstration.   Downside is that I expect the failure rate to be higher. If we get the chance over the weekend Rob and I will try one out to see how realistic it is to make these in the field.
course tooling 5

 

 

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