That´s a typical medieval crossbow. Its bow is made of horn, backed with 2- 3 layers of sinew, wrapped with sinew and covered with birchbark. The bent ends or recurves of the bow are made of another spliced in piece of horn or antler. These crossbows are told to draw 150- 300lbs. The bow measures in length 30″ – 35″, at the handle width is 2″, at the ends( just where the recurves are beginning) width is 11/2″, thickness is about 3/4″ at the center tapering down to 1/2″ at the ends. The recurves are measuring about 31/2″ in length.
The horn slats are assembled like the stones of a dry stone wall, no running through seams or joints. It would be no problem to use thinner horn slats, it depends on the available material, so their could be 7 rows of horn slats adjoined. The lengthwise joints are butt joints at a 45 angle.
First is to glue the orange slats, then insert the black slats, last add the red and green slats to the sides. So there are 5 rows of slats. The back of the assembly of horn slats will be cut even, rasped to an even thickness and width, than the tapering in width and thickness has to be done. The rectangular cross- sections will be rounded more towards the belly of the bow. Time for a first test of tiller(even bending), drawforce, any sounds of breakage??.
In the drawings of the cross-sections the sinew- backing is marked blue.
The cross- section at the left is another way to do a hornbow for a crossbow. Just glue at least 2 slats together lengthwise one upon the other and sinew- back them. This is an easier way. But it is not recommended for really high drawweights up to 200- 300lbs……………..and it´s hard to find horns measuring such long enough with a roughly even required thickness. The dry stone wall method makes a more effective use of the entire horn.
Next volume is focused on the next step of the making of the “dry stone wall”, and I hope so, on sinew- backing in general.
After having flexed and sanded 2 pairs of waterbuffalo- horn you´re really smelling strong, the smell in my nose reminds me of my first visits at the barber around the beginning 60ties. Even if protected by a mask, it will last 2 days if one will be able again to smell more than horn. I´m used to be around with animals, every morning I´ve to clean up the stable of our horses and our donkey. Donkeys could really stink heavily. I like the smell of animals much more than the smell of cheap perfumes and deos, but the smell of horn, above all when worked with blunt tools, is second to none.
Before the glueing horn needs to be grooved and precoated. The grooving of the horn and the wooden core of a hornbow along the glue- lines is a hot topic. There are well reputated horn- bowyers confirming that there is no historical proof for such a grooving. Don´t believe them, the very opposite is true. Grooving makes much sense, the glueline will become 3- 4 times wider, a grooved cross- section is much more stable. The stability of the glue- line of a hornbow is a must, cause of its resilience the horn will always try to reconstitute its original shape. To not groove means to overlook this fact, maybe these hornbowyers are somewhat lazy. It takes half an hour per hornbow to make a proper grooving. A well done hornbow is expensive and the grooving is enforcing its quality. A well grooved glueline should be a main charcteristic when buying a hornbow.
I prefer to make multi- tools. This grooving tool works for to make grooves of different width and depth. The one used for the grooving of the crossbow- slats is at the left. I use cabinet scraper- blades and made the grooves with round files or triangular files. The blade is fixed between to wooden logs of manageable size with a slot working as a guide. The slot is a bit more in width than the slats.
The grooved slats are cut at their ends in a 45 angle for a lengthwise overlapping.
When making a hornbow for a crossbow the slats have not to be of even thickness or length, the surfaces have to be planed and grooved. Next volume will be focused on the construction- principle of it.
When making composite bows the traditional way hideglue or fishglue is the glue of choice. Modern glues are way of being traditional, they ar poisonous and brittle. Natural glue- lines are much more durable, they don´t need flexibilizers which will discharge in the course of time. The production of natural glues is a very sense making use of what we would call waste. It´s a holistic handling of a slaughtered animal.
There are different qualities of hide glue. Don´t use liquid hide glues. They are made liquid by flexibilizers, the glueline will become brittle.
The best hideglue is made of the skins of cattle, its adhesive power is very high(for the experts: 450- 480 bloomgrams, 160mPas). You can get it as a granulate, the serious dealer of my choice is: Kremer in Germany.
Before soaking the grains I usually had to clean up the glue- pot. It´s hard to do, I soak it with warm water for to dissolve some leftovers, for the final cleanup I´ve often to use a hammer and a chisel.
Next morning add water: for a good quality hideglue you´ve to mix finally 1 time glue and 2 times water. Now the solution has to be heated up to 140 F, to much heat will destroy the collagen of the glue and it will become worthless.
I use the hot water reservoir of our kitchen stove, the glue pot fits the reservoir exactly. Such a kitchen stove is a great tool when making hornbows, for a proper glueing warmth is indispensable.
The Ottoman hornbowyers are told to have used a bowl filled with blistering charcoal.
My wife doesn´t resist such an abuse of our kitchen, cause its me to cook most times and I´m a passionate baker too, I bake bread almost every 2nd day and like to make some cake. I guess my wife has never realized that I use the kitchen stove for to make bows.
Horn is very dense, so it has to be decomposed or digested by precoating it with a thin solution of hide glue.
At least the horn has to precoated 3 times with a thin solution of hideglue. When glueing horn, bamboo and dense woods with natural glues the precoating is a must. Warmth is as important as the precoating, about 50% of all hornbow- breaks are caused by glueing failures. The horn and the glue are mainly made of collagen, as a protein, it loves warmth, but take care, 140F is the limit. I guess nobodies nose will ever forget the horrible smell of somehow burnt horn or hideglue. My nose is the best thermometer for warming hideglue and horn.
Before every glueing or precoating the horn has to be warmed!
After the 3rd precoating the hideglue is warmed up to 140F, the grooved and precoated slats are warmed, coated with the hideglue and compressed with clamps.