MEDIEVAL STYLE SLING BOW

I based my design on a medieval crossbow and used a commercial high quality slingshot to make a very accurate target- practice device. The length allows better aiming and steadiness when shooting.

Very straight kiln- dried hardwood is essential for this project.

(WARNING: This is very powerful item NOT meant for children and must be handled with extreme caution! Also, ammunition can RICOCHET if it hits a hard surface, so take care and wear safety glasses.)

Materials

High quality steel frame slingshot

2”x 2” x 36” poplar 

3/8”X 1.5”X 13” poplar

1/2”x 4” machine bolt (with straight shaft)

cotter pin

1” and 1.5” washer

2” lag screw

2- 1.5” x 3.5” metal mending plates + mounting screws

Rigid nylon tubing, 1/4” i.D.

1- 2”, 10/32 machine screw and nut

2- 1.5” wood screws

marbles, or steel shot

Carpenter’s glue

Shoe polish

Tools will be mentioned in each step. For safety, I recommend using a drill press and power mitre saw, although this can be built with portable power tools if careful.

Determine the maximum draw of your slingshot by pulling it back fully and measuring from the frame to the ammo pocket. Mine was 20”. (Yours may be different)

Measure this distance from one end of your 2x2. Make a punch mark centred at this spot

Measure 7” from the punch mark to the other end of the wood and cut it square.

 Turn it on its side and draw a line 5”from the end to 1” down the edge and cut the angle. Glue the removed wedge to the bottom under the angled cut to make a handle.

Cut a 5” piece from the remaining wood using the same angle and glue it to the bottom at the front of the rail opposite the handle. (This will support the slingshot.)

 Clamp, or brad nail the glued pieces and wait till dry. Sand and round off any rough edges.

Drill a 7/8” hole at the punch mark but only drill deep enough for the head of the bolt to fit. 

Finish the hole straight through with a 9/16” bit. 

Cut the nylon tubing to the height of your ammo pocket. (make 2)

Set these at the front edge of your 1” hole with a 1/4” gap between them. Mark the hole locations and drill slightly smaller than your 1.5” wood screw diameter.

Remove the grip of your slingshot and centre the frame at the front support. Drill the wood between the frame slightly smaller than the diameter of your lag screw.

Locate the mending plates on each side so the first mounting hole is 12” from the front and the pivot hole for the trigger is 3/4” below the frame.

Drill the mounting hole locations slightly smaller than the mounting screws. (both sides)

Cut the 1/2” bolt to 3.5”. Use a hack saw. File the cut edge flat and bevel the round edge with a file. *NOTE: Your bolt must be long enough so that when actuated, it just clears the top of the nylon tubes.

Drill through the bolt about 1/4” from the cut edge, large enough for the cotter pin to fit.

Make sure the 3/8” hardwood is 1.5” wide. Cut the length to 13”

Drill a 3/16’” hole through the width at the 3” mark.

Bevel the bottom of the mounting plates at a 45 degree angle leaving the bottom front mounting hole as a pivot for the trigger. (Use metal shears) Clean up all sharp edges with a file.

I rubbed brown shoe polish on the frame and trigger and buffed it to give an antique finish and protect the wood.

Drop the ammo release actuator into its hole and install the cotter pin. This keeps it from falling out when upside down.

Install the nylon tubes (ammo pocket holders) using the 1.5” screws.

Install the slingshot using the lag screw and double washers (Big washer closest to slingshot frame) before tightening, make sure the ammo pocket, when pulled back, is just above the nylon tubes.

Install the trigger pivots with mounting screws. 

Install the trigger with the machine bolt and nut. Leave the nut loose so the trigger can actuate properly. After testing, you may want to replace the nut with a Nyloc, or use some Loctite to keep it in place.

IMPORTANT: Check the photos for trigger operation and loading before proceeding!

DO THIS OUTSIDE IN AN OPEN AREA WITH NO ONE NEARBY. 

Put a marble in the ammo pocket. Pull it back and wedge it between the nylon tubes.Keep one hand between the trigger and frame as a safety.

 AIM AT A SOFT TARGET AND FIRE.

Set up a target to get an idea of accuracy. I suggest some cans or a disposable aluminum pan. DON’T AIM AT A HARD SURFACE AS AMMO CAN REBOUND AT YOU OR OBSERVERS. 

The target pictured was placed 5 feet high and I fired 5 shots from a 20 foot distance.

Enjoy and be safe!