Author Archive | Nic Westermann

Chisels and Gouges

About 18 months ago I read a great article in Woodcarving Magazine, Michael Painter was discussing the design of tracery chisels, they looked interesting and I learnt a lot about their design . Using the principles he described I came up with my swan necked bowl gouges. They are a tool I am especially proud of as they are so different to the bowl gouges that other makers offer. One of the reasons I called them Swan necked is that I find these tools graceful and current alternatives are known as doglegs, which, well, aren’t.

I met Michael at a show earlier in the year and started describing the bowl gouges I had made; he firmly corrected me saying they were chisels not gouges  ( my view is that if I made the tool I can call it what I want, but thought it better to bite my tongue. )   he looked skeptical but I produced said tool and he was quite impressed, showing me the original tracery chisel that I had seen in the article he wrote. I took some measurements and we also discussed making some fishtail chisels. I enjoy trying something new and this was the result.

fishtail and tracery 1

The day I finished this set I had a phone call from a customer that had bought a bowl gouge from me asking  if I could make fishtail chisels, he sent an old one down that he had snapped the corners off- not all old tools were made from from perfectly tempered steel obviously.

When it arrived the next day it was interesting to compare  it to my new tracery chisel and the greenwood swan neck.

bowl gouge origins 2

They may look very different but the techniques to make them were identical,  shape and scale varied but it showed me how closely related the different branches of carving actually are.

I have been wanting to make a one handed version of my gouges, the same wide blade and sweep but more compact neck and handle. Here is the first attempt, it still needs more testing and tweaking but first impressions are good. But the part that really makes me happy is that I get it name it the Cygnet.

gouge

Yandles spring show and Lie-Nielsen

Yandles was as ever a great show; a  unique atmosphere, I enjoy the fact that it is not aimed at green woodworking; there are a few of us demonstrating but the power tools are definitely king here; however we draw a good crowd, and find ourselves made very welcome. I am increasingly finding more in common with other branches of woodworking, the idea that there is conflict between different disciplines of woodworking is a shame, I really enjoy seeing different ways of working wood.

Rob and I set to work forging the first axe of the year. Rob was not impressed with my new sledge and stuck with last years model.

IMG_6759

The show was also a  chance to  meet up with old friends including the guys from the The Japanese tool study group; had the chance to adjust a plane for then, I am a big fan of tools than can be fixed with the gentle application of a hammer. Demonstrating just a few yards away was Deneb Puchalski from Lie-Nielsen Toolworks; was very interesting listening to his take on sharpening; a mix of diamond and traditional waterstones were his preferred method. Deneb ordered an Axe from me over 6 months ago now and like many people has had to wait whilst I work through the list; however the chance presented itself for him to have a hand in making  his own axe.  Rob stepped aside for the last stage and Deneb struck for me.

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You can see that Deneb opted for the new, shorter sledge also the lower anvil is a mixed success; better for the striker but it does leave me a bit bent over. In the workshop a high anvil and a pallet on the strikers side balances things out much better.

We also had a chance to sort out the final tweaks to an order of spoon carving sets that Lie Nielson have placed  for the courses Peter Follansbee is teaching for them in May. I just had time to get the sets ready and sent out to them.

IMG_6845

 

I am very proud to have worked with them on this and other orders; it is fantastic to supply such a prestigious company. Although they are used to much larger quantities than I am able to supply they understand very well my productions methods and are keen for me not to compromise quality for quantity. However the range of my tools that they would like to stock is ever growing,  I am in the process of signing another 6 year lease on my workshop, some changes will soon be made which should help me to expand production in the future.

 

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.

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