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Jean Thibodeau
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 Posted: Tue 01 Jul, 2008 9:16 am Post subject: Sword testing by makers. |
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I was wondering about sword testing but not the kind done by the purchaser but by makers to check on their quality control and as a way to learn how to make a better or at least know what their swords perform.
This could be destructive testing or just a pass or fail test of their swords before they leave the shop.
I would also make a distinction between what a large mass market maker might do as product testing and what small one person or high quality small manufacturer might do: The large makers might be motivated to improve their product or just maintain a minimal level of durabllity/safety while the small shop/maker is often in the business for more than just making a living ( Although making a living is a factor for a full time maker ), and the small maker is closer to a collector/historian in mindset as well as being a craftsman/artist.
So, although it might be interesting to know if and how the big volume makers test their swords or try to improve their swords I'm more interested in what the high end people test or not test: This would include people like Peter Johnsson, Tinker, Angus Trim and small companies like OlliN, A & A, Albion etc ...
I sent an e-mail to Mark Grzybowski asking a similar question and I think a copy/paste of my question and his answer would be a good way to start this Topic with some " Raw meat "   instead of just my intro above.
( Note: Asked and got permission to copy Mark's reply to me here to jumpstart the Topic )
My e-mail question to Mark;
| Quote: | Mark;
I have a question for you that might make an interesting Topic on " myArmoury " :
Just curious about how you test your swords when you get them back from heat treat to assure yourself that they are as durable as they should be ? This obviously can't be " destructive " testing as the sword is supposed to go to the customer after successfully passing your tests.
The tests can't be too extreme or repeated too many times, like bending is fine to see if it can be bents a bit more than one would in normal use but if repeated past a certain point, " amount " of bending and the number of times bent can produce some metal fatigue and reduce the normal service life of a blade.
Maybe hitting a padded but hard surface a few times ?
With the 3 blades you made, before the last one that worked, some tests may have been unnecessary as the problems would have been obvious like softness or warping in the first two blades but the last one that broke probably looked fine until it broke.
I also assume that you may in the past have made a few blades to test too destruction or seen it done at Albion enough to give you an idea what a sword should be able
to take and at what point things cross over into just too much ! At what point use becomes abuse. ( I imagine this can be a narrow or wide grey zone where some
individual swords fail sooner than others even if of the same identical design ). |
Mark's first reply:
| Quote: | Hey Jean,
You're probably right that a sword testing topic might be an interesting one. That is if I could make it sound all technical and insightful  . Kind of like how the swords I make end up feeling the way they do, a lot of it is by done feel and reading how the blade responds, which can make it difficult to put down in words that offer useful information.
In each batch of blades that get heat treated, one of them is sacrificed for destructive testing.
One of the tests involves trying bend the blade to the point of failure, which can be quite a task. There have been some that would not break no matter how far I was physically able to bend them. That's a scary test. Actually, only a few of the blades have broken from this (with the blades heat treated by vendors I feel confident in using), but instead take a set. The proportion of how much set takes place compared to the degree of bending is also quite useful information.
Along a similar note, I made a jig to fit in my vise that is capable of producing a lot more localized and powerful bending pressure. It can produce about 1 1/2" of deflection over a span of around 6", or even greater, depending on where you place the center pressure point. The blade gets tested along it's length to read the amount of warpage or possible breakage that occurs. This is the same jig that is used to take the warps out of a blade that may take place during grinding, and every blade is tested with this process, although not to the extreme that the test piece is. Comparing how the customer blades respond to the sample piece gives a decent indication of the heat treat.
Another test is striking the test blade against a block of mild steel. It's not a straight on, perpendicular strike, but more of a slicing action. The blade's edge isn't made sharp, but left at about 1 mm. Obviously, edges that chip out would not be good. Neither would excessive deformation of the edge. I have to say that it is pretty cool to see a sword blade cut chunks out of a piece of steel.
Every blade also goes through some (relatively) lighter test cutting into wood. The edge of my bench has really been chewed up over the years. Of course, I wouldn't recommend chopping down trees or anything with a sword. Again, it's more of a slicing than perpendicular action.
I hope that you're that not asking about this because your sword broke....
I also hope that this answers your questions. I'll keep thinking about the walking stick ideas. I have to go and separate some shrimp in my aquarium at the moment. I don't know why they feel the need to fight all of the sudden.
Mark |
You can easily give up your freedom. You have to fight hard to get it back!
Last edited by Jean Thibodeau on Tue 01 Jul, 2008 9:34 am; edited 1 time in total
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Jean Thibodeau
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| Posted: Tue 01 Jul, 2008 9:30 am Post subject: |
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Here is my reply to Mark's first e-mail and his reply to me. ( Made a second post to make the reading of all this manageable:
| Quote: | Mark;
First the blade didn't break or anything else bad happen to it. ( Just to make sure you can read the rest of this stressfree ....... LOL ).
I did hit a lamp fairly hard " once " but couldn't find the exact spot of contact at first, I think I saw a very VERY slight dull spot that is/was hardly visible: I used a diamond hone to get the edge just a little bit sharper ( paper cutting sharp ) but didn't go crazy here trying for razor sharp as it's better to have a sturdier edge I think.
Oh, used a white ceramic and then a very hard and smooth steel to lightly burnish the edge. ( All this very very light and not perceivably increasing the width of the secondary edge ). The diamond hone barely attacks the steel by the way, so I assume that because of the differences in thickness of the blade the edges may be harder than the 52 R.C.
of the tang and forte of the blade at it's thickest.
Reading your reply I must say that it does inspire a great deal of confidence in the durability of the blade. ( WOW ........ LOL ).
I think that with your experience testing your blades in such a systematic way you have a much more realistic view of what amount of bending is the normal amount that a sword can cycle through thousands of times without it being significant to accelerated blade damage i.e. metal fatigue, microfractures etc. You should also be very aware of when you are in the " destruction " zone or close to what would be abuse.
In other words when one of " us " buyers flex a blade or see a lot of flexibility we ( I ) tend to be alarmed way before we should and worry that the blade might take a set or break ....... LOL.
Oh, apart from resistance to destruction I read into your reply that you also test for balance and handling, and that apart from the numbers/blade statistics, you test for " feel ".
I think a lot of this makes the difference from a sword maker artisan/artist making nice looking swords and a true swordmaker making using swords that one could bet one's life on if we were in " period " an lives depended on a sword not failing.
Handling a very heavy sword like the " RavenWolf " : I find that in handling this sword going from guard to guard one can make it easy or difficult depending on if one fights the sword or goes along with it ! By this I mean that there is a natural point on the sword, when in hand, where the sword wants to rotate and that when moving the sword one can move it laterally fighting the sword's inertia or one can rotate around this rotation point and move from guard to guard with very little wasted energy.
I'm getting used to this sword's handling and it is making all my other swords feel light by comparison ........ LOL, but in a good way: The Tritonia is now feeling sort of " puny " !
Oh, can I quote your reply and use it for the Topic on sword testing I want to start ? I think that what you wrote about below is sword making/design insider " GOLD " and would be interesting to just about everyone, and I certainly would like to learn more.
Cheers.
Jean |
| Quote: | Funnily enough, I was feeling the same thing when grinding out sword blades. All of the other ones felt light in comparison to yours.
"Feel" has always been a big thing with me, whether it deals with making art, sculpting wood, making swords, or whatever. For me, the sense of touch is just as, if not more, important than sight. It's probably the main reason why I do so much of my work by hand. When shaping a piece of wood, I seriously don't even look at the surface, but rely on my hands to tell me the high and low areas.
I was planning on getting more into how I approach sword making, but I'm running late on time with the emails, so that will have to wait.
If any of my emails are helpful in any way, feel free to use it in your topic.
Mark |
I found Mark's comments very interesting and I'm curious about how this Topic will evolve: I hope Mark will add more about his approach to testing and sword making and I hope other makers may add their input as well as people asking questions and giving their opinions. ( As usual ).
You can easily give up your freedom. You have to fight hard to get it back!
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Dan Dickinson
Industry Professional
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| Posted: Tue 01 Jul, 2008 10:09 am Post subject: |
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Looks like it should be a good topic Jean.
Here's an example of some testing that Albion does (I'm assuming this is a random quality check or perhaps testing of a new model) http://youtube.com/watch?v=D2mDMS6-884
I've also heard that every blade is tested on the oil drum rim after grinding, but I'm not sure of the validity of that statement.
Dan
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Jean Thibodeau
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| Posted: Tue 01 Jul, 2008 9:26 pm Post subject: |
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| Dan Dickinson wrote: | Looks like it should be a good topic Jean.
Here's an example of some testing that Albion does (I'm assuming this is a random quality check or perhaps testing of a new model) http://youtube.com/watch?v=D2mDMS6-884
I've also heard that every blade is tested on the oil drum rim after grinding, but I'm not sure of the validity of that statement.
Dan |
What I conclude from the tests is that should I thrust with a sword with a flexible tip fairly hard against armour ( Theoretically that is ) and that the armour, maille, plate or brigantine successfully stops the point the sword may bend quite a bit and spring back undamaged unless the thrust in question is truly pushed very hard in spite of it's ineffectiveness.
I would think that the point and sword would be pulled back before damage to the blade occurred and that one would try something else.
With moderate resistance the blade might start to bend but straiten out into the target once the penetration started to happen. A fast thrust might mean penetration while a slow push might cause more bending than piercing ?
In the tests the bending that causes a set seem to be those over 45 degrees at least and more so around the 90 degrees of repeated bending. The bends that cause real damage look like almost 180 degrees where the point is pointing completely back towards the guard.
I guess one thing I'm curious about is what amount of bending causes ZERO accelerated wear/damage to a blade and at what point does some cumulative damage happen to a blade ? Degree of bending as well the number of bending/straitening cycle being a factor in what would be considered normal use of a blade.
You can easily give up your freedom. You have to fight hard to get it back!
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Jean Thibodeau
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| Posted: Sun 06 Jul, 2008 10:27 pm Post subject: |
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Seeing a sword bend always makes me think of cumulative sword damage over the useful life of a sword, but the tests read about in Mark's e-mail reply makes me think or re-think how " alarmed " I should be when one of my swords bend on impact ! ( Mostly " theoretical impacts " happening in my imagined use of the swords: I tend to sort of " baby " my swords ).
In short the amount of bending a flexible blade can take without causing cumulative damage to the blade is much greater than I believed or perceived ! If one avoids true abuse or actual destructive testing extremes a sword should be able to survive thousands if not millions of bending cycles before metal fatigue becomes a factor.
Sword damage could also be divided into:
1) Major: Where bending or impact causes a broken blade or one that takes a set or major chipping of the edges.
This effectively means a destroyed sword that ceases to be useful. ( Except that a bent sword can be straitened but becomes much more prone to bend at the same point or break the next time it is stressed ).
2) Minor: Nicks and dings and scratches, that although distressing in the " New car with a first scratch way ", doesn't affect the continued use of the sword as a fighting tool. This damage sort of inevitable if the sword is used and to a degree manageable by resharpening and polishing.
Anyway giving the Topic a little " bump " as I would like to hear what others think or their personal experiences if they have " challenged " their swords by putting them to use. ( Use not abuse. ). Obviously, also what knowledgeable sword makers can tell us about the limits of sword use and realistic expectation one should have about the durability of a well made sword.
You can easily give up your freedom. You have to fight hard to get it back!
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