Question about integral bolsters

A. G. Maisey · 21st November 2013, 04:51 AM

I'm not going to talk about ethnic knives, or historic knives, I'm going comment only on why a maker would choose to use an integral bolster rather than a bolster or guard that is pinned and soldered.

If you pin and solder you need to drill through the blade.

Holes in blades create a weak point.

A bolster forged from, or fire welded to the blade has the opposite effect:- it strengthens the blade.

Its not necessarily because knives have a habit of breaking at the junction of blade and hilt, its just that an integral bolster is superior construction to a bolster pinned and soldered.

Then there is the factor of craftsman preference. If the maker is primarily a smith, it is easier for him to make a blade with an integral bolster than it is for him to fiddle around with drill/pin/solder. If the maker is primarily a cutler, it easier for him to drill/pin/solder than to consider an integral bolster. The cutler will get a forging that he needs to turn into a knife, a flat blade without the lump that needs to be filed to shape for a bolster is easier for him to work with.

I have made many blades in damascus with integral bolsters, I made custom knives and blades for a fairly lengthy period, about 20 years from memory, and I was an early member of the Australian Knife Makers Guild. I was primarily a smith, not a cutler.

Emanuel · 21st November 2013, 04:55 PM

Thank you Timo and Alan for your explanations.

I am approaching the questions from a historical point of view and while I understand the advantages of forging a blade with an integral bolster, I am also trying to understand how this preference or technique spread in a certain area and time frame.

For almost four hundred years the yataghan type of blade in the Western Ottoman empire is forged flat, with a decorative bolster soldered or fixed to the base of the blade with an adhesive, not pinned. Ivory, horn, or metal scales are pinned to the tang to form the handle and a decorative strip is affixed around the edges of the handle.

At the same time, small cutlery in Italy and in Central Asia appears with a forged or welded bolster. In Western Europe this has late-medieval roots. Knives with integral bolster are also made in Istanbul in the 1700s.

Then at some point around 1800, or maybe earlier, we see instances of the yataghan type of blade with a forged bolster, in Anatolia, Kabylia, and Bulgaria. This method does not replace the older one, and is not related to blade size in the Bulgarian context, but in Anatolia appears to accompany large blades with T-section. The forged bolster is is not a technique used in other sword or sabre designs anywhere near the Ottoman empire at the time, but some earlier 17th century Tatar sabres seem to use it.

The sporadic adoption of this method of bladesmithing makes me wonder if we have a peculiar, itinerant group (possibly ethnic) moving around and spreading this bladesmithing technique and preference. If we do, then what is the direction of this movement?

The style of very long and heavy yataghan with very substantial integral bolsters seems to become popular again towards the end of the 19th century in rural Anatolia. In this context it supposedly becomes a show feature, part of costume.

Emanuel

Emanuel · 16th February 2016, 06:10 PM

I'll update this thread with a yataghan dated 1239/1826, with Turkish ribbon pattern welding and T-spine and integral bolster construction. This makes it the earliest example of integral bolster on such a sword I've seen, and contemporary with the earliest dated flyssa.

Originally posted in "3 large yataghan...".

kronckew · 16th February 2016, 07:00 PM

my karaculak yataghan,or shepherd's knife from bulgaria has an integral bolster. way back someone mentioned it might be 18c. (photo) blade is not 't' section.

structurally, the blade is like a beam, if you drill holes in it on the neutral axis which generally runs down the centre of the blade and tang, you lose very little if any structural strength. the further away from this neutral axis, the greater the compressive and tensile stress that acts on the material. on blades without integral bolsters, they usually have a sudden reduction in blade width where the blade enters the guard, if any and separate bolster, in order to fit inside the dimensions of the grip. this produces a structural incongruity and especially if the 'corner' is square, will allow progressive cracking and failure at this notch due to the high stress that a notch causes there. an integral bolster neatly avoids this.

a khukuri does not have an integral bolster, many now sport 'habaki' style bolsters to guide it into the scabbard, but khukuris are mostly differentially hardened and tempered such that the spine and tang/blade juncture are left a lot less brittle that the cutting 'sweet spot'. a bent khukuri (or sword) can be bent back into shape, a snapped one cannot easily be mended in the field.

ariel · 17th February 2016, 03:55 AM

I have a yataghan looking like Bulgarian karakulak, with Sarajevo-like "nuclear" decorations on the handle and integral bolster, dated 1838 ( NOT Islamic date!)

I think we may be talking about parallel development. If bladesmiths had a common idea of a blade, what prevented them to have a common idea of an integral bolster?

Emanuel · 17th February 2016, 03:19 PM

I think if we looked we would find that most all yataghan blades,and most other swords are heat treated in this manner. There is no reason to harden the tang/blade transition area.

The karakulak underscores my point.
Basically ALL Balkan yataghan don't have integral bolster.
Karakulak and Ionian yataghan ALL HAVE integral bolster. These things were contemporary in the same geographic area.

The cutler/swordsmith separation brings more questions to mind.
We have early knives in Istanbul and Italy with integral bolster.
Then we have short sword yataghan in the Balkans without integral bolster.
At the same time we have big knife karakulak in Bulgaria and very long sword yataghan in Ionia (western Anatolia) with integral bolster. Who made the knives and who made the swords?

My thinking is that we're seeing commonalities between bladesmithing traditions ultimately associated with common populations, specifically the Yoruks of both Thrace and the Ionian coast.

ariel · 17th February 2016, 04:27 PM

My only hesitation relates to the fact that Turkmen knives do not have integral bolsters. On the contrary, they had to be made of some kind of copper alloy to be used for slaughtering animals in a "halal" fashion.

16th February 2016, 06:10 PM	#3
Emanuel Member Join Date: Jul 2005 Location: Toronto, Canada Posts: 1,242	I'll update this thread with a yataghan dated 1239/1826, with Turkish ribbon pattern welding and T-spine and integral bolster construction. This makes it the earliest example of integral bolster on such a sword I've seen, and contemporary with the earliest dated flyssa. Originally posted in "3 large yataghan...". Attached Images

16th February 2016, 07:00 PM	#4
kronckew Member Join Date: Mar 2006 Location: Room 101, Glos. UK Posts: 4,215	my karaculak yataghan,or shepherd's knife from bulgaria has an integral bolster. way back someone mentioned it might be 18c. (photo) blade is not 't' section. structurally, the blade is like a beam, if you drill holes in it on the neutral axis which generally runs down the centre of the blade and tang, you lose very little if any structural strength. the further away from this neutral axis, the greater the compressive and tensile stress that acts on the material. on blades without integral bolsters, they usually have a sudden reduction in blade width where the blade enters the guard, if any and separate bolster, in order to fit inside the dimensions of the grip. this produces a structural incongruity and especially if the 'corner' is square, will allow progressive cracking and failure at this notch due to the high stress that a notch causes there. an integral bolster neatly avoids this. a khukuri does not have an integral bolster, many now sport 'habaki' style bolsters to guide it into the scabbard, but khukuris are mostly differentially hardened and tempered such that the spine and tang/blade juncture are left a lot less brittle that the cutting 'sweet spot'. a bent khukuri (or sword) can be bent back into shape, a snapped one cannot easily be mended in the field. Attached Images Last edited by kronckew; 16th February 2016 at 07:12 PM.

21st November 2013, 04:51 AM	#1
A. G. Maisey Member Join Date: May 2006 Posts: 6,989	I'm not going to talk about ethnic knives, or historic knives, I'm going comment only on why a maker would choose to use an integral bolster rather than a bolster or guard that is pinned and soldered. If you pin and solder you need to drill through the blade. Holes in blades create a weak point. A bolster forged from, or fire welded to the blade has the opposite effect:- it strengthens the blade. Its not necessarily because knives have a habit of breaking at the junction of blade and hilt, its just that an integral bolster is superior construction to a bolster pinned and soldered. Then there is the factor of craftsman preference. If the maker is primarily a smith, it is easier for him to make a blade with an integral bolster than it is for him to fiddle around with drill/pin/solder. If the maker is primarily a cutler, it easier for him to drill/pin/solder than to consider an integral bolster. The cutler will get a forging that he needs to turn into a knife, a flat blade without the lump that needs to be filed to shape for a bolster is easier for him to work with. I have made many blades in damascus with integral bolsters, I made custom knives and blades for a fairly lengthy period, about 20 years from memory, and I was an early member of the Australian Knife Makers Guild. I was primarily a smith, not a cutler.

21st November 2013, 04:55 PM	#2
Emanuel Member Join Date: Jul 2005 Location: Toronto, Canada Posts: 1,242	Thank you Timo and Alan for your explanations. I am approaching the questions from a historical point of view and while I understand the advantages of forging a blade with an integral bolster, I am also trying to understand how this preference or technique spread in a certain area and time frame. For almost four hundred years the yataghan type of blade in the Western Ottoman empire is forged flat, with a decorative bolster soldered or fixed to the base of the blade with an adhesive, not pinned. Ivory, horn, or metal scales are pinned to the tang to form the handle and a decorative strip is affixed around the edges of the handle. At the same time, small cutlery in Italy and in Central Asia appears with a forged or welded bolster. In Western Europe this has late-medieval roots. Knives with integral bolster are also made in Istanbul in the 1700s. Then at some point around 1800, or maybe earlier, we see instances of the yataghan type of blade with a forged bolster, in Anatolia, Kabylia, and Bulgaria. This method does not replace the older one, and is not related to blade size in the Bulgarian context, but in Anatolia appears to accompany large blades with T-section. The forged bolster is is not a technique used in other sword or sabre designs anywhere near the Ottoman empire at the time, but some earlier 17th century Tatar sabres seem to use it. The sporadic adoption of this method of bladesmithing makes me wonder if we have a peculiar, itinerant group (possibly ethnic) moving around and spreading this bladesmithing technique and preference. If we do, then what is the direction of this movement? The style of very long and heavy yataghan with very substantial integral bolsters seems to become popular again towards the end of the 19th century in rural Anatolia. In this context it supposedly becomes a show feature, part of costume. Emanuel

17th February 2016, 03:55 AM	#5
ariel Member Join Date: Dec 2004 Location: Ann Arbor, MI Posts: 5,503	I have a yataghan looking like Bulgarian karakulak, with Sarajevo-like "nuclear" decorations on the handle and integral bolster, dated 1838 ( NOT Islamic date!) I think we may be talking about parallel development. If bladesmiths had a common idea of a blade, what prevented them to have a common idea of an integral bolster?

17th February 2016, 03:19 PM	#6
Emanuel Member Join Date: Jul 2005 Location: Toronto, Canada Posts: 1,242	I think if we looked we would find that most all yataghan blades,and most other swords are heat treated in this manner. There is no reason to harden the tang/blade transition area. The karakulak underscores my point. Basically ALL Balkan yataghan don't have integral bolster. Karakulak and Ionian yataghan ALL HAVE integral bolster. These things were contemporary in the same geographic area. The cutler/swordsmith separation brings more questions to mind. We have early knives in Istanbul and Italy with integral bolster. Then we have short sword yataghan in the Balkans without integral bolster. At the same time we have big knife karakulak in Bulgaria and very long sword yataghan in Ionia (western Anatolia) with integral bolster. Who made the knives and who made the swords? My thinking is that we're seeing commonalities between bladesmithing traditions ultimately associated with common populations, specifically the Yoruks of both Thrace and the Ionian coast.

17th February 2016, 04:27 PM	#7
ariel Member Join Date: Dec 2004 Location: Ann Arbor, MI Posts: 5,503	My only hesitation relates to the fact that Turkmen knives do not have integral bolsters. On the contrary, they had to be made of some kind of copper alloy to be used for slaughtering animals in a "halal" fashion.