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Post by ShooterMike on Jan 5, 2010 2:35:08 GMT
WOW, the waggle test was a serious revelation to me. I waggled some single handers that cut remarkably well and the pivot point on all of them were within an inch of the tip (AT1315, two AT1557s, AT MM Type XVI prototype, Albion Squire Line Knightly, Albion Knight with reduced pommel, Albion Laird, AT "Harley" XII.1 prototype). Then I tested some swords that are just OK cutters (AT1312, stock Albion Knight, Albion Norman). Their pivot points were 2-2.5 inches from the tip. And one sword that's a pretty sub-par cutter was something like 3.5-4 inches from the tip.
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Post by Tom K. (ianflaer) on Jan 5, 2010 3:35:23 GMT
Good to know Mike. I'm going to have to play with this waggle test some more as I think I may not be doing it well. which is funny to me since I used to be quite a good juggler and balancing poles was something I did well for a while.
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Post by Deleted on Jan 5, 2010 10:18:28 GMT
Me too, I've read the ARMA article and also a SFI article where Gus, Tinker and Peter Johnsson went on and on elaborating how important pivot points are. Anyways, I tried a waggle test; hold the sword tip down with two fingers where hilt and guard meet and shake it like on guy at SFI said... result: nothing, blade didn't whobble at all; now hold the sword and tap the pommel: Juhu, found the CoP. What? What am I doing wrong?? Btw, I used my custom H/T longsword and while it's not an ATrim, it's still a very good sword so the CoP CAN'T be the pivot point. Help??
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Post by Deleted on Jan 5, 2010 11:09:43 GMT
On the eve of battle; the steely-eyed commander looks over his anxious troops. Taking a stick, he begins to draw the following in the sandpit:Hrothgar, are you sure you got all that?(Sorry, I had too...LOL ;D)
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Post by Tom K. (ianflaer) on Jan 5, 2010 20:46:01 GMT
the only problem with what you have drawn in the sand there my friend is that it is a formula for an untapered stick. tapering chases all these critical points inwards. if we don't know the amount of tapering and the modifications to the formula for the change in mass distribution this equation becomes pretty useless.
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Post by YlliwCir on Jan 5, 2010 21:01:01 GMT
Thinking about this stuff makes my head hurt. I am totally dumbfounded.
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Post by Deleted on Jan 5, 2010 21:28:47 GMT
the only problem with what you have drawn in the sand there my friend is that it is a formula for an untapered stick. tapering chases all these critical points inwards. if we don't know the amount of tapering and the modifications to the formula for the change in mass distribution this equation becomes pretty useless. I was joking. For me, a sword feels good and performs; or it does not. I acknowledge that this may be good stuff for a smith to know, but, this thread has gotten way to hardcore for me. Forgive me for getting out of here before you guys start whipping out the slide rulers and tetrahedron dragon dice.
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Post by Deleted on Jan 5, 2010 21:31:47 GMT
You pretty much summed it up for me too, Odingaard
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Post by Deleted on Jan 5, 2010 21:44:22 GMT
As already stated, any type of sword can receive damage from usage. In the case of the Brescia; it's not the first time I have read about Albions getting chipped/nicked easily. In fact, this was one reason why I only buy second-hand Albions and never new ones. They have QC issues just like every other company. Hell, I know of people who have gotten new Svantes that had casting flaws, uneven central ridges, crooked tips, etc. Of course, that is to be expected by every sword producer, nobody's quality control is perfect... But this sword was actually just fine... In the link I posted earlier Lancelot posted results of hardness test on the damaged sword. Forte of the blade was softer at about 45Hrc but towards the tip and edges the hardness was Albion's usual a bit under 55 Hrc. So the hardness and quality of the Brescia was ok, the damage was done on the bone which is to be expected especially if the edge was a bit oversharpened. And the damage was really not that bad...
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Post by Tom K. (ianflaer) on Jan 5, 2010 22:20:48 GMT
Sorry Odingaard, I missed that, but if you will take your slide rule out for a second you can see that you posted generally the right mathmatics, just for a straight stick. I think it woul get us into the ball-park though.
Luka, I did not see that, thanks for pointing it out. that's pretty interesting.
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Post by Deleted on Jan 5, 2010 23:11:34 GMT
Me too, I've read the ARMA article and also a SFI article where Gus, Tinker and Peter Johnsson went on and on elaborating how important pivot points are. Anyways, I tried a waggle test; hold the sword tip down with two fingers where hilt and guard meet and shake it like on guy at SFI said... result: nothing, blade didn't whobble at all; now hold the sword and tap the pommel: Juhu, found the CoP. What? What am I doing wrong?? Btw, I used my custom H/T longsword and while it's not an ATrim, it's still a very good sword so the CoP CAN'T be the pivot point. Help?? Chenessfan, the blade's not supposed to wobble at all, you're trying to get the sword to smoothly pivot back and forth in mid-air, like when people do the old "look my pen is made of rubber!" trick. And when you smack the pommel, yes you're finding what's commonly called the center of percussion, but it's not ACTUALLY the center of percussion-->it's one of the primary nodes of vibration and it has nothing to do with the natural pivot point that transfers no movement to the pivot point in your hand, which is what was originally called the center of percussion, because that's what you use to "percuss" a target, which is what we're trying to find anyway because....... ............................... Ah, screw it. Tinker designed that blade, so it's excellent anyway. And we've seen that you can cut quite well with it, and it handles magnificently, so who really cares? You've got a good sword, sir. You don't need all this mumbo-jumbo to confirm it.
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Post by Deleted on Jan 6, 2010 2:32:08 GMT
About the expensive sword with the damaged edge, taking that much damage from plain leather is a bit ridiculous. I think that sword is far to sharp, I'm sure historical swords of that style rarely (or never) approached that sort of sharpness, simply because it makes the edge to delicate, and it's also absolutely unnecessary. Swords were made to kill people, not neatly sever plastic bottle lids! (If you can shave with a European style sword its most likely much sharper than it's historical counterpart, I believe technique matters more than making a blade as sharp as possible.)
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Post by Deleted on Jan 6, 2010 5:53:48 GMT
Easiest way to find the pivot point is to attach a bit of colored chalk to the hilt and tip with some easy to remove tape. Then on a very large sheet of paper place the sword and grip the handle where you would hold it and swivel left and right. Connect the edges of the two arcs diagonally and where it crosses is the pivot point.
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Post by Deleted on Jan 6, 2010 10:14:05 GMT
That's cool, Cold! I'll try it!
Luna, I know the H/T sword is good I just wanted to figure out how to find the pivot points so I can consider pivot points when making swords myself. I never doubted that the H/T had the pivot points where they should be, but I doubt that I will able to make a good sword without knowing how to find them so I can change distal taper and stuff until everything fits. Now I hope Cold Napalms way works for me... only need to get such a big piece of paper.
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Post by Tom K. (ianflaer) on Jan 6, 2010 13:52:34 GMT
that is very interesting Cold, I'll have to try it but I have a question: what part of the hilt? the cross guard? the pommel? the center of the grip? where?
any reason you couldn't use sidewalk chalk and a driveway? (carefully of course)
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Post by Deleted on Jan 6, 2010 17:12:55 GMT
Opps, I should have said to attach the chalk to pommel...so it´s end to end. And you can use the sidewalk as long as it´s flat.
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Post by Deleted on Jan 6, 2010 17:19:56 GMT
Uhhhh...........Correct me if I'm wrong, but wouldn't that just give you the main pivot point on the hilt, not the secondary one near the tip of the blade? As in, the one that is entirely determined by where you grip the sword?
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Post by Deleted on Jan 6, 2010 17:27:15 GMT
It gives you the secondary pivot point (the one near the tip). The tip arc should be small and the pommel arc large. If you have no tip arc, then your sword has a pivot point at the tip. My hanwei tinker bastard sword has that. my albion crecy is about 1 inch from the tip.
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Post by Deleted on Jan 6, 2010 17:30:43 GMT
Ah, I see. Thanks for the clarification. That's a simple and straightforward way to do it.
By the way, is that the fullered or non-fullered bastard sword? I've been looking at that model with an interested eye.
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Post by Deleted on Jan 6, 2010 17:43:36 GMT
non fullered. It´s a nice sword...but the wood they use for the handle is rubbish. With the stock handle the pivot point was about .5 inches from the tip. I put a denser and sturdier handle on mine.
Basically the method I mentioned is the waggle test...just more accurate and easier to see.
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