Unredy-xbow-art

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Unredy-xbow-art - 12/26/18

"Building the Unredy Combat Crossbow" by THL Dana the Unred.

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NOTICE -

This article was added to this set of files, called Stefan's Florilegium, with the permission of the author.

These files are available on the Internet at: http://www.florilegium.org

While the author will likely give permission for this work to be reprinted in SCA type publications, please check with the author first or check for any permissions granted at the end of this file.

Thank you,

Mark S. Harris...AKA:..Stefan li Rous

stefan at florilegium.org

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Building the Unredy Combat Crossbow

by THL Dana the Unred

Part One

The Prod.

The prod can be made from almost any solid fiberglass 60 inch bow in the 30 to 40 LB range, so long as the limbs bend equally from the center) and the bow is without a molded in shelf or cut out.

About half of the bows I've built use the Bear 60 In, 30 to 35 LB recurve (cost between $40-50 new) youth bow with the rubber handle cut off and the limbs cut down to 48 inches and re-notched. (Note, the cut and re-notched ends will need to be sealed with either polyester resin or epoxy) With a four-inch brace height this should give about 55 to 60 LB at 20 inches. Subtracting the brace height this give a starting IP of 880 to 960 IP. The other half of the bows where built using whatever came to hand in the 30 to 40 LB range with either the draw adjusted to give the desired IP or a rawhide ballistic cover applied.

A properly applied rawhide cover will add between 100 to 200 IP to a prod. For rawhide I use a large rawhide dog bone from Petsmart (about $10). Try and find one with no visible holes. Soak in water for several hours, untie the knots in the end and cut into 3 inch by 50+ inch strips (should get 3 per bone). Cut a hole 1-inch from one end in the center of a strip, sized to slip over one bow tip. Stretch the hide along the face of the bow as much as you can and mark and cut the second tip hole. Slip the second hole over the second tip. The rawhide should be under moderate but not extreme tension. Now fold the hide over to the belly of the bow and trim it so that the edges are about 1/4 inch short of meeting in the center. Stitch the edges together using a baseball or herringbone stitch and drawing the edges together. Resoak the hide and bow to keep it easy to work as need while sewing. Lastly fold the end flaps over and lash firmly the set the bow aside to dry for at least 24 hours. When dry the rawhide can be decorated with any dark ink and sealed with shellac. If this is done right it will remove almost all of the set from the bow and as I said add 100 to 200 additional IP to it at the same draw.

We have found that most bows are left strung all of the time and will lose power over a couple of years as the prod takes a set. Building the bow without a cover at near the power you want will allow you to add the cover after a year or so of use and bring the power back to where you want it without replacing the prod. Should the cover add a bit too much power just raise the brace height to bring the power back to what you want.

Should your Kingdom limit crossbows to 600 IP just don't cut the bow down this way by adjusting the brace height you should be able to get very close to 600 IP. With the standard design tiller and easily switch between 600 and 1000 IP depending on which prod you mount for any given day.

Again referring to Lord Greywolf's photos you will see the prod is mounted to the tiller with U-bolts. This is done for ease of disassembly during travel. A few taps with a drift and it's apart. The U-bolts are held together with a piece of armor grade leather across the front between the two U-bolt which are then double nutted with the top nut being self locking.

 Another option that I use on my personal bow is to use line lashing around the cross pin used for the U-bolts and across the front of the bow. This still allows the pin to be drifted out for breakdown and once the knots are not under tension they are easily untied to reuse the line at the event. If you are comfortable with line and knot work this is a better-looking option.

Part Two

There are two basic methods to construct the tiller. The first is to work the tiller from a solid piece of wood. The trigger housing and bolt track, are cut with a router or hand chisel. The rest of the work can be done with basic saws, hand or power planers, drill press or brace and bit, and sandpaper. This method is much easier with a good selection of power tools.

I have built bows with equal success from 8/4 hardwood, 4x4 fir.

The basic dimensions of the tiller are as follows. Fore stock (string notch to front of bow), generally between 18 and 24 inches depending on the power of the prod used and the desired power of the bow.

I have customized bow weights from 700 to 1000 IP. Just by varying the length of the fore stock.

The string notch is ¾ x ¾ inch. The bolt channel should be about 3/8" deep.

Tail stock (front of string notch to back of bow), 14 to 15 inches work well for most people but this may be changed as desired so long as the trigger doesn't extend past the back of the tiller for safety reasons.

The tailstock can be left full width or tapered to reduce weight.

Bolt clip stock (1 1/4 x 1/8"), trigger pin stock (1/4" round), bolt for pin (3/8" x 4 1/2"), and spring (1 1/2" long that fits comfortably over the bolt). I get these items from Lowes, Home Base or Ace Hardware.

Heating with mapp gas and using a vice and crescent wrench bends the triggers and bolt clips.

The U-bolts are 3 to 3 1/2" long. Any shorter and the cross pinhole will infringe on the vertical reinforcement dowel.

The trigger stock (3/4" or 1" x 1/4").

The vertical reinforcement dowels are either 5/8" or ¾" sometimes cut from scrap tiller wood or from a contrasting color wood. Holes are cut with a Frostner bit. The leading reinforcement dowel should be tangent to the prod notch. The other dowels are spaced evenly along the bolt notch.

You can make things much easier by drilling and setting the reinforcement dowels prior to routing or cutting the bolt grove. Otherwise a lot of tedious sanding will be required. Just be sure the dowels won't go through the bottom of the finished belly or into the trigger housing.

The second, laminated method is easier if power tools are limited. You will need both 1/2" and 1/4" laminating stock. Many box stores carry both 1/2" and 1/4" x 4" x 48" drawer stock in poplar and red oak. Cheaper methods are to re-saw and plane the stock from 2 x 4 or 4 x 4 stock, and if the tiller is to be painted I see no reason not to consider plywood.

I find it useful to build a pattern from 1/8" hardboard with all of the cut outs and alignment holes then use that to trace cut lines on each laminate piece. You can even use the pattern for a cutting guide. This insures that a minimum of finish plane work and sanding are required. Using a pattern and a router with flush trim bit can reduce handwork to almost nothing.

The core of the tiller is made using 1/4" stock in the center precut for trigger housing, prod notch, string notch and bolt guide. Half-inch pieces also precut are glued to this. Note I use short dowels through the 1/4" center and into the 1/2" core pieces to maintain alignment while gluing. When the core is dry I drill and set the vertical reinforcement dowels (see pictures above), cut off flush and sand or plane fair. Last I laminate the cheek pieces, using the same alignment dowel as before. The cheek pieces can be of either 1/4" or 1/2" depending on how rugged you want the bow to be and if weight is an issue Next drill the hole for the lift pin, seat, fit and adjust the trigger and do final sanding and shaping.

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