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Cole Sibley
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 Posted: Tue 31 Oct, 2006 11:49 am Post subject: Rondel blade cross-sections |
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Are there any examples of circular cross-sectioned (or otherwise unsharpened) dagger blades in the 1300-1500 timeframe? Are trinangular rondel blades fairly common (I assume this means single edged as opposed to double edge diamond cross section)? I understand the 'stiletto' may have been more common without an edge, but it is generally from a later time period, correct?
Any information would be greatly appreciated. After some excellent research here at myArmoury I started a Rondel project, but it failed miserably and I'm back to square one and looking to start again (I have a wonderful piece of steel, but it is decidedly round in cross section).
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Justin King
Industry Professional
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| Posted: Tue 31 Oct, 2006 12:53 pm Post subject: |
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Triangular blades were fairly common, particularly on rondel daggers. Some had an acute enough edge angle to be fairly sharp, some did not. There are examples that have no cutting edge and were apparently intended solely for thrusting. Rondels are thought to have been primarily military/combat weapons, as opposed to utility blades, so it is not surprising that some would be designed specifically for exploiting gaps or weak spots in plate armour.
I have never seen an example with a round blade section, but that dosent mean there weren't any.
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Bryce Felperin
Location: San Jose, CA Joined: 16 Feb 2006
Posts: 552
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| Posted: Tue 31 Oct, 2006 2:07 pm Post subject: |
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I believe it depended on who you were. As I recall knights and nobles, because they could afford a separate dedicated knife, tended to have more pointy rondels specifically designed for hole punching whereas those not wealthy tended to use a rondel with a more standard knife edge.
A friend of mine had rondel made that is round and very pointy. It was made from an SKS bayonet. He said he's broken boards and punched through car doors with it. It's a very evil weapon.
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Al Muckart
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| Posted: Tue 31 Oct, 2006 11:33 pm Post subject: Re: Rondel blade cross-sections |
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Hi Cole,
| Cole Sibley wrote: | | Are there any examples of circular cross-sectioned (or otherwise unsharpened) dagger blades in the 1300-1500 timeframe? Are trinangular rondel blades fairly common (I assume this means single edged as opposed to double edge diamond cross section)? I understand the 'stiletto' may have been more common without an edge, but it is generally from a later time period, correct? |
The really thickly triangular rondel daggers didn't necessarily even have cutting edges at all, they were purely thrusting weapons.
I don't know whether there are any examples of circular cross-sectioned spike-with-a-hilt type daggers, but I'd be somewhat surprised if there were, for a couple of reasons.
Firstly I would imagine forging a truly round bar is quite a bit trickier than forging a triangular sectioned blade. I have no true idea how to do either but a round bar has more faces than a triangle so I'm guessing it's harder to get even. Thinking about it I can't think of any common pieces of medieval weapons which are long but round in cross-section rather than faceted. I'd love to hear from the makers on here whether I'm way off base or not. I guess you could do them with a swaging tool or something.
The second, and more compelling, reason I'd be a bit surprised if they existed is that I don't think they'd actually work very well. A tapered round section is harder to force through things like steel and cloth and person than one with corners is.
Part of the reason for this is that the corners, even if they aren't really sharp, play a critical role in spreading the initial hole created by the point. They act as conentrations of the outward force created by the wedge action of the tapered blade passing through the hole, and create tears in the material, allowing the blade to penetrate more easily. Without them the spreading force of the wedge is evenly distributed around the circumference of the circular cross section, creating compression instead of tearing and requiring a great deal more force to move the material out of the path of the blade.
The other part of the reason is that a round cross section has a greater area than a triangular one of the same width. The area of a circle is pi * r^2 so for something say, 10mm across, it's cross-sectional area would be pi * 5^2 or about 78.5 square millimetres.
Now my math is terrible, but google tells me that the area of an equilateral triangle is given by (s^2) * (sqrt 3) / 4. (see http://www.mathwords.com/a/area_equilateral_triangle.htm). If the triangle is 10mm on a side, the same width as our round section above, its area is (10^2) * (sqrt 3) / 4 or about 43.3 square millimetres -- significantly less than the circular cross-sectional area at the same width.
This means that if you assume the same taper, the round cross-section will by trying to spread the penetrated material faster than the triangular cross section as well as being hampered by the fact that it's round section is already harder to push through the penetrated material.
A triangular blade with hollow-ground faces will be even easier, due to the more prounounced corners and lower cross-section.
You can see this effect for yourself if you have access to some leatherworking kit. Modern leatherworking awls are diamond in cross-section rather than round and are far far easier to push through leather than a needle even half as wide.
I have attached a picture trying to illustrate the difference in cross section. The triangles are centered by height, not the actual "center" of the triangle so they appear a bit off but my graphics program (inkscape) doesn't have an easy way to arrange them more usefully.
 Attachment: 13.08 KB
Difference in cross-sectional area between a round and triangular cross-section.
--
Al.
http://wherearetheelves.net
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Russ Ellis
Industry Professional
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| Posted: Wed 01 Nov, 2006 6:57 am Post subject: |
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Nicely reasoned Al. Someone will no doubt come along with a picture that shows a round rondel any second now and blow us out of the water but for what it is worth I think you are correct. 
As far as this project goes Cole, wouldn't it be fairly simple to turn that round bar into a triangular one assuming you have access to the proper tools?
TRITONWORKS Custom Scabbards
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Geoff Wood
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| Posted: Wed 01 Nov, 2006 8:50 am Post subject: |
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Not a rondel, not even a dagger, since no decent handle, but some (e.g. the Mk II of the British no. 4 for the SMLE) of the socket bayonets had a spike that appeared (I've only seen pictures, never held one) round in section until very near the tip, where it was faceted to a point.
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Geoff Wood
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| Posted: Wed 01 Nov, 2006 9:25 am Post subject: |
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Another example, again, not a rondel and not of relevance to the period, but in this case it is a dagger of sorts. The trocar and cannula used to treat bloat in cattle has a round section (which makes sense given that the cannula is a tube) with, again, a faceted tip on the trocar. if anything, this example confirms what Mr Muckart said about the triangle edges and tearing, since you wouldn't want to tear too much in this case, but you do need to get reasonable penetration to get to the gas in rumen or reticulum.
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