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Michael Edelson




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PostPosted: Tue 18 May, 2010 10:55 am    Post subject: COG question         Reply with quote

When measuring a sword's center of gravity and the sword has a cross that dips down in the center, do you measure from the center of the cross (B below) or from the edge of the blade where it emerges from the cross (A).



In the sword pictured below, there is actually a 1/4" difference.

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Nathan Robinson
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PostPosted: Tue 18 May, 2010 11:00 am    Post subject:         Reply with quote

I measure from the center... but I don't really care either way, personally, as I use the numbers only to communicate a general sense of the sword's dynamics and not anything particularly specific or scientific.
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Michael Edelson




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PostPosted: Tue 18 May, 2010 11:04 am    Post subject:         Reply with quote

I thinkl it's important for consistency's sake to have a standard. Say you and I order the same sword and we both report our COGs. You report 3.75" and I report 4". People might say, wow, there is a lot variation in this model, when in fact it would be the same COG measured in two different places.
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Vincent Le Chevalier




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PostPosted: Tue 18 May, 2010 11:16 am    Post subject:         Reply with quote

These days I measure everything from the junction cross-handle, which is neither of the points you propose Happy Think about how the handling would vary if the cross was a bit wider: not much. The position that matters is where the cross meets the handle...

I agree 100% that setting a standard is important. Especially for CoG, since small variations can matter a lot.

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Nathan Robinson
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PostPosted: Tue 18 May, 2010 11:20 am    Post subject:         Reply with quote

Michael Edelson wrote:
I thinkl it's important for consistency's sake to have a standard. Say you and I order the same sword and we both report our COGs. You report 3.75" and I report 4". People might say, wow, there is a lot variation in this model, when in fact it would be the same COG measured in two different places.


But that's my point: for me that isn't a lot of variation, specially considering the source (ie, the end user and a tape measure). I understand this context. And even without it, for me, It matters not much. I don't get caught up in that stuff. Mileage varies.. a lot. Most would disagree with me entirely.

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Michael Edelson




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PostPosted: Tue 18 May, 2010 11:25 am    Post subject:         Reply with quote

Vincent Le Chevalier wrote:
These days I measure everything from the junction cross-handle, which is neither of the points you propose Happy Think about how the handling would vary if the cross was a bit wider: not much. The position that matters is where the cross meets the handle...

I agree 100% that setting a standard is important. Especially for CoG, since small variations can matter a lot.

Regards,


Actually a thicker, heavier cross would affect both handling and COG.

Also, there is no meaningful COG measurement (I'm half siding with Nathan here). Its only meaning is in comparing it to that of other swords to see the difference in handling. Therefore it really doesn't matter if you measure from the cross handle junction, the tip of the pommel or the tip of the sword, as long as it's consistent.

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Vincent Le Chevalier




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PostPosted: Tue 18 May, 2010 11:48 am    Post subject:         Reply with quote

Michael Edelson wrote:
Actually a thicker, heavier cross would affect both handling and COG.

I was assuming a cross of the same weight, of course, just a different shape...

Michael Edelson wrote:
Also, there is no meaningful COG measurement (I'm half siding with Nathan here). Its only meaning is in comparing it to that of other swords to see the difference in handling. Therefore it really doesn't matter if you measure from the cross handle junction, the tip of the pommel or the tip of the sword, as long as it's consistent.

OK, consistency is enough... But to judge the difference in handling you'll need both CoG and cross width then, because the relevant point for your hand is the junction cross-handle (H). If you measure the CoG from H you don't have to store and communicate that other dimension.

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Michael Edelson




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PostPosted: Tue 18 May, 2010 12:23 pm    Post subject:         Reply with quote

Vincent Le Chevalier wrote:

OK, consistency is enough... But to judge the difference in handling you'll need both CoG and cross width then, because the relevant point for your hand is the junction cross-handle (H). If you measure the CoG from H you don't have to store and communicate that other dimension.

Regards,


That's a good point. I think I'll play around with that, thanks.

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PostPosted: Tue 18 May, 2010 12:59 pm    Post subject:         Reply with quote

I'm with Vincent. Since it is generally assumed that you have one hand on the top of the handle where it meets the guard, that is your pivot point and you feel the location of the CoG relative to it—so that would be the ideal place to measure from.

Of course rapiers and complex-hilted swords for which one loops a finger around the cross-guard present a slightly different situation. But honestly, the extent to which I refer to CoG is usually to see if it's on the order of 2" vs 6", not 4.122" vs 4.053", so it doesn't matter all that much to me anyway. ;-)

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Thom R.




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PostPosted: Tue 18 May, 2010 1:21 pm    Post subject:         Reply with quote

I measure it the same way as Vincent - partly because he already beat me up on this one already Laughing Out Loud but it makes the most sense to me now as that is the logical place (the handle/cross junction) to suspend the sword to find a sword's pivot point as well.
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Jean Thibodeau




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PostPosted: Tue 18 May, 2010 4:13 pm    Post subject: Re: COG question         Reply with quote

Michael Edelson wrote:
When measuring a sword's center of gravity and the sword has a cross that dips down in the center, do you measure from the center of the cross (B below) or from the edge of the blade where it emerges from the cross (A).



In the sword pictured below, there is actually a 1/4" difference.


I would generally measure at (B) but if the guard had an extreme " dip " or extension onto the blade I would probably measure at (A) but for practical purposes a half an inch either way doesn't make mush of a difference to me in how I perceive the handling of a sword unless I had two identical swords with just the guard being different in shape but almost the same weight.

Consistency would only be important if two people where communicating about the same sword model but where measuring from different points and that this caused confusion or questions about consistencies in quality control when the swords are made to be very close in specifications.

Other makers who hand guide the grinding of their swords or forge them would have more variability in specifications and even more if they have been making the same model over many years i.e. the specifications change as the maker gets better or make modifications based on later research. I would think that this might be apparent with A & A and Del Tin who may have tweaked their designs over the years.

Albions are probably much more consistent over many years of production within the same model sword but even they have occasionally changed some of the design parameters to correct some things like too slim a point that may have been fragile by changing the profile and/or the distal taper of some of their swords.

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Maurizio D'Angelo




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PostPosted: Tue 18 May, 2010 5:41 pm    Post subject:         Reply with quote

I think the point is important. In your comments you may have the same sword three different COG. The point of Vincent, is technical, but not in common use, I think the B is most commonly used, point A can be legitimate. I believe that we must standardize the points: one point B?
The problem moves to the length of the blade where I measure? total hilt's lenght ?
There are many definitions in the swords that are technically wrong, but we still use them because of common use.
It is classified as Oakeshott, allows us to understand why we all know what it means XIIIa. or XI, we have common definitions.
If the definition is 90 mm. from the guard, by all means call in its entirety.
If is point A, in this case, I must add: 100 mm from the midpoint of the guard.
If the point is like Vincent say, I have to add: 115 mm from junction cross-handle (H)
No. Too many definitions, the more common use. B. , is better Happy

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