LASHING

LASHING 

Sulekha Rani.R, PGT Chemistry, KV NTPC Kayamkulam 

1. Square lashing 

Square lashing is a type of lashing knot used to bind poles together. Large structures can be built with a combination of square and diagonal lashing, with square lashing generally used on load bearing members and diagonal lashing usually applied to cross bracing. If any gap exists between the poles then diagonal lashing should be used.

Square lashing steps

1.    Begin with a clove hitch on the vertical pole beneath the horizontal pole and tuck the loose end under the wrapping.

2.    Wrap in a square fashion (behind the back pole, over the front pole, etc.) about three times around the poles.

3.    Frap two or three times, pulling often to work the joint as tight as possible.

4.    Tie two half hitches around the horizontal pole

5.    Cinch the half hitches into a clove hitch, an additional clove hitch may be added if desired.

When the turns are taken around the vertical pole they should be inside the previous turns. The ones around the cross pole should be on the outside of the previous turns. This makes sure that the turns remain parallel and hence the maximum contact between the rope and wood is maintained. 

OR 

• Tie a clove hitch to upright stick. Be sure a knot is on side of stick and long end of chord is in front of you. Place other stick across upright stick.
• Pass long end of chord down over cross stick and around in back of upright stick. Bring cord to front under cross stick. Then bring up and over cross stick and in back of upright. Bring down over cross stick as in beginning.
• Wind exactly this way about three times. Pull cord tightly as you workout make it lie neatly beside earlier turns.
• Now you are ready for "frapping". Wind the cord about three times between the two sticks to tighten. Pull as tight as you can.
• To finish, make two half hitches around one stick. Or tie the two ends together with a square knot. Trim the ends and tuck them underneath the lashing.

Uses:
To make racks for towels or bathing suits, coat hangers, picture frames.

2. Diagonal lashing 

 

Diagonal lashing is a type of lashing used to bind spars or poles together, to prevent racking. It is usually applied to cross-bracing where the poles do not initially touch, but may by used on any poles that cross each other at a 45° to 90° angle. Large, semipermanent structures may be built with a combination of square lashing, which is stronger, and diagonal lashing.

Baling twine has sufficient strength for some lashing applications but rope should be used for joining larger poles and where supporting people sized weights.

Diagonal lashing steps

1.    Begin with a timber hitch around the juncture of the two poles.

2.    Make three turns in each direction - tightening steadily throughout the turns.

3.    Make two frapping turns, tightening the joint as much a possible.

4.    To end, make two half hitches

5.    Cinch the half hitches into a clove hitch

A lashing stick can be used to safely tighten the joint. Strength will be improved if the first turn is 90° to the timber hitch and if care is taken to lay the rope turns parallel with no crossings. 

 A diagonal lashing is used to secure two poles, which are likely to be pulled, or to spring, apart.

1. Commence with a timber hitch.
2. Make three turns following the directions of the timber hitch.
3. Now make three turns round the other fork.
4. Tighten the lashing with two or three frapping turns, and complete with a clove hitch on any of the poles.

3.  Sheer lashing 

Shear lashing uses two or three spars or poles, 15 - 20 feet (6.1 m) of rope.

Tying: To tie a shear lashing, begin with a clove hitch around one spar. Then wrap the free end of the rope around both spars about seven or eight times. Make about three fraps around the lashing, and end up with a clove hitch on the second spar.

Use:  Tying spars or poles together when they must subsequently be swung apart slightly in a scissors motion (shear legs). Shear lashings may also be used in place of round lashings to join spars of unequal thickness in a straight line

A sheer lashing is used either to form 'legs' from two poles (Type 1) or to join two poles together make a longer pole (Type 2).

Type 1:

1. Start with a clove hitch round one of the (not both) and twist the free end round the rope.
2. Make about ten turns round both poles; do not make these too tight otherwise you will have difficulty with the frapping turns.
3. Make two frapping turns between the poles.
4. Finish off with a clove hitch round the other pole.

Type 2:

1. Place the two poles to be lashed together side by side. They should overlap by at least a quarter of their lengths; otherwise the extended length will not be firm.
2. Two lashings will be needed, both of which are made in the same way. Star with a timber hitch round both poles.
3. Wind exactly this way about three times. Pull cord tightly as you workout make it lie neatly beside earlier turns.
4. Now you are ready for "frapping". Wind the cord about three times between the two sticks to tighten. Pull as tight as you can.
5. To finish, make two half hitches around one stick. Or tie the two ends together with a square knot. Trim the ends and tuck them underneath the lashing.

Uses:

To make racks for towels or bathing suits, coat hangers, picture frames.

 

 

 4. FIGURE OF EIGHT 

   So we come to the Figure of Eight Lashing, which is used to lash three poles together in order to form a tripod of "gyn". Lay the three spars together so that the end of the center spar points in the opposite direction to the ends of the outer spars. The lashing starts with a clove hitch around one of the outside spars at a reasonable distance from the end. Six or seven turns are then taken quite loosely round the spars, working under the over alternately, like a Figure of eight. The lashing is finished off with loose frapping turns and clove hitch on the other outside spar. If the lashing is too tight it will not be possible to bring the legs to form an equilateral triangle on the ground.