The following text is by Pioneering Legend, Adolph Peschke, author of the renowned 1993 edition of the Boy Scouts of America’s Pioneering Merit Badge Pamphlet, from his treatise entitled “Pioneering With Laminated Spars.” Some additions have been included in this post, for the purpose of practical elaboration.
Suggestion: Prior to using them to build a project, to eliminate the lashings from slipping on the smooth surfaces of the Laminated Spars, wrap six inches of friction tape tightly around the areas where the spars will intersect one another .
Just what are laminated spars? They are similar in size and length to the natural tree spars that have been used for many years bt Scouts in the construction of Pioneering structures i.e.: bridges, towers, and in other camping projects.
This kit of Laminated Spars are fabricated using pieces made from standard lumberyard shapes. Here, two or more wood shapes are glued and nailed together to obtain a strong cross-section and length of the finished spar needed in building structures using ropes and spars. This method of gluing and nailing pieces of wood together has long been used by wood workers to gain the strength that a single piece of wood does not provide.
Important to Scouts is the fact that the same knots and lashings used with natural spars in building bridges, towers, etc. can be used with these Laminated Spars.
Because natural spars have become harder for Scout troops to obtain due to changes in conservation practices and the fact that suitable species of trees that provide the best spars are just not available for harvest in many areas of the country, Laminated Spars are a means for the Scout troop to have its own “kit” for a full program of “boy sized” Pioneering for teaching – learning – advancement – or just fun and action projects.
T h e T r o o p K i t
- 4 ea. Trestle Legs, 2-1/4″ x 2-1/4″ x 6′
- 4 ea. Ledgers Upper/Lower, 2-1/4″ x 2-1/4″ x 4′
- 1 ea. Transom, 2-1/2″ x 3″ x 4′
- 4 ea. “X” Braces, 1-1/2″ x 2- 1/4″ x 6′
- 12 ea. Walkway Cross Spars, 1-1/2″ x 3″ x 3′
- 4 ea. Walkway Cross Spars, 1-1/2″ x 3″ x 4′ (a little longer than specified but more thrifty)
- 4 ea. Walkway Laterals, 2-1/2″ x 3″ x 10′
- 2 ea. Walkway Planks, 2″ x 8″ x 8′
Refer to the Pioneering Merit Badge Pamphlet for knots, lashings, and building instructions for the Single Lock Bridge.
Materials: It is not necessary to buy choice lumber. A good construction grade should do, if you can buy from a lumberyard that lets you pick and select what you buy.
Note: The lumberyards refer to size and shapes in nominal dimensions, i.e.
- 2″ x 4″ actually is: 1-1/2″ x 3-1/2″
- 2″ x 6″ actually is: 1-1/2″ x 5-1/2″
- 1″ x 4″ actually is: 3/4″ x 3-1/2″
- 1″ x 6″ actually is: 3/4″ x 5-1/2″
Reference the sizes shown on the sketches are actual i.e. 3/4″, 1 and 1/2″, 2 and 1/4″, 2 and 1/2″ , 3″. Also lengths are stated in feet: 4′, 6′, 8′, etc. When possible, select species Fir or Yellow Pine. Avoid large knots and “White Wood.”
Fabrication of Laminated Spars – All work should be done or supervised by adult leaders and/or skilled craftsmen.
Materials needed: one 1 x 6 x 4-foot., one 2 x 6 x 4-foot, one 1 x 6 x 6-foot, one 2 x 6 x 6-foot boards
These lumberyard shapes may be bought in 8 and 12-foot. lengths.
Rip lumber to 2-1/4-inch strips and cut to 4 and 6-foot lengths.
Spread glue evenly on both pieces and nail with 6D Hot Dip Galvanized Nails along both sides with 10-inch staggered spacing. Leave clearance for 1/2-inch Round Over Router Bit. Paint the ends of the 4′ spars white, and the 6′ spars red.
THE TRANSOM SPAR: The Transom Spar is a stout spar used on many different bridges to support the walkways where they meet at the center of the bridge. When the walkways are lashed to it, it makes a continuous unit.
Material needed: The Transom Spar can be made from one 2 x 4 x 8-foot stock. Rip the lumber to 2-1/2 inches and cut it into two 4-foot lengths.
Spread glue evenly on two sides and nail using 10D Hot DIpped Galvanized Nails. Drive nails from both sides at an angle (to prevent penetrating the opposite side). Router 1/2-inch round over all four edges. Paint ends white.
Materials needed: Four 1 x 6 x 6-foot boards. Rip each piece into three 1-1/2-inch strips.
Note: Once you have ripped the three pieces into into 3/4 x 1-1/2-inch strips, it is easier to run the 1/2-inch round over the edges. See the sketch BEFORE routing. One piece gets 2 edges rounded, and the other two get one edge only. Becasue the strips are narrow, it is best to route round overs before nailing.
Use 1 and 1/4-inch Ring Shank Nails.
The finished spar is 1-1/2″ x 2 -1/4″ x 6 feet.
Paint the ends red.
WALKWAY CROSS SPARS (as per The Troop Kit)
Materials: Six 1 x 6 x 6-foot boards and two 1 x 6 x 8-foot boards
These spars have the same cross section as the “X” Braces above. Twelve of them are made from 6-foot sections and then cut into 3-foot lengths, and four of them are made from 8-foot sections and cut into 4-foot lengths.
Materials: eight 2 x 4 x 10-foot boards.
Rip these to 3 inches. It will take two to make each 3-inch x 3-inch x 10-foot spar. Round over with 1/2-inch bit on two edges only. Spread glue and nail from both sides using 10D Hot Dipped Galvanized Nails.
Note: Drive nails on an angle to prevent the tip from penetrating the far side.
Paint ends black.
Tools: The most practical method to reduce sizes of lumberyard shapes to the dimensions called for on the sketches is to use a circular table saw for ripping and an electric router to make the round-over cuts on the edges.
Caution: All power tools must be operated only by skilled adults, in accordance with the manufacturers specifications. Work in a safe place and follow safety rules.
Older Scouts may help with gluing and nailing.
A few “C” clamps will be needed to keep the pieces in line while being nailed.
Glue: Use Tightbond II (Blue Label) and spread with a roller to get a complete and even spread.
Nails: Use Hot Topped Galvanized Nails. Your spars will get wet from time to time so rust-proof nails are the best choice.
Paint: Small cans of brush on are best and much cheaper. A 4-inch gauge marker for the ends will make the job neater.
Note: Use the Boy Scouts of America Pioneering Merit Badge Pamphlet for instructions in knot tying and lashing. With this Troop Kit of Laminated Spars, you should be able to build the Single Lock Bridge.
Adolph E. Peschke
Some more notes: It will definitely pay off to wrap the spars with friction tape at the points where the lashings will be tied! (Same goes for slick, green bamboo.) In lieu of tape, use a bastard cut wood rasp file and form a slight roughed out indentation at the places where lashings will be applied, to eliminate sliding on the slick surface of the spars.
The colors for coding the spars at the tips are suggestions and bot universal. The colors chosen can be in accordance with those used by your unit, district, or council.
Prepare eight 2-1/2″ x 3″ x 8′ spars and four 2-1/4″ x 2-1/4″ x 6′ spars and you have the poles required for a Double A-Frame Monkey Bridge.