Some tips in approaching farm fencing

Press, Volume CXI, Issue 32666, 23 July 1971, Page 17

Some tips in approaching farm fencing

Fencing is a costly business. Each year farmers buy more than seven million fence posts, which cost more than s2om. But recent developments in fencing, can help keep these costs to a minimum.

No matter which way you look at it, fences are vital for efficient fanning. They must have lasting qualities, as well as containing stock or keeping out unwanted stock. They must also be as cheap as possible without losing any effectiveness. and should have a low maintenance input. This article aims to look at the various materials available for fencing, as well as the current types of fence that are being erected. Fencing is usually a matter of personal preference. Experience and knowledge of the land will often overide any other factor in determining the most suitable fence. By discussing each of the basic fencing items separately I will be able to point out' their advantages, as well as their disadvantages. Wooden posts are by far more commonly used than their concrete equivalents. They are usually of soft wooded timbers, e.g. Pinus radiata logs, pressure treated with chemicals. The addition of the chemicals allows the posts to be used below ground level. Tight control is enforced by the Timber Preservation Authority to maintain a very high standard of treated posts. Care should be taken when buying posts that they carry a symbol showing that they have been treated for ground retention. Wooden posts are cheaper, lighter and just as durable as concrete posts. While the days of concrete posts are not over, their use on steep hill country is certainly limited. A plain concrete post has an average breaking load that is less than a 3in Radiata post.

Reinforced concrete posts are stronger. Battens add considerably to the cost of a fence, if used in excess. The stockholding ability of a fence depends on a combination of tension, spacing of wires, and spacing of battens. This allows for numerous combinations ofposts, wires and battens. Provided a 10 wire. 121 gauge fence is maintained at a tension of 3001 b per wire, i.e., 30001 b per fence, four treated battens per chain should be sufficient. The holding power of a staple is very important, especially with the large numbers of wooden posts and battens that are being used. Where the timber is soft, long barbed staples should be used. All staples must

be fully galvanised otherwise rusting will occur where they come in contact with the wire. The staggering of staples when battening assists in keeping the battens in place. There are two main types of wire currently used today. They are 12} gauge high tensile and No. 8 gauge. Although No. 8 wire is thicker and has been in use for a good number of years, 12J gauge is fast becoming the most popular type of wire. In its early days, there were many queries and comments. One of the most common complaints was

“12} gauge isn’t as good as No. 8.” To check this statement the N.Z.A.E.I. at Lincoln College were asked to test them. They reported that the 12} gauge performs as well as No. 8 under conditions of fire and freezing, provides an adequate strain, overstrained. They stated that around 3001 b tension provides adequate strain. This tension can be easily checked if permanent strainers incorporating tension meters are used. These are only slightly dearer than the normal type of permanent strainer. Other advantages of 12} gauge are: It costs less than half the price per chain of No. 8. It has a per coil length that is 2.8 times longer than a coil of No. 8. However, care should be taken when working with 12} gauge wire. Although it is nearly as strong as No. 8, because of its thinness there is not as much galvanising. Hammering can easily damage the wire, or remove some of the galvanised coating. Tests on the wire also show that temperature has a greater effect (i.e. contracting or expanding) on the thicker No. 8 than on* the 12} gauge. A 10 degree! C. drop in temperature! over a 10-chain length of! fence can cause up to Jinl contraction in No. 8, and Jin! movement in 12} gauge.! This means that if 10 chains! of fence is erected one sum-1 mer, it will contract over! the winter and shift the! strainers. Next summer, the! rise in temperature will ex-1 pand the wire, causing a| loss in tension. This will be| up to 201 b for a No. 8 gauge! fence, and 31b for a 12}| gauge. Comparisons have shownl that unless a tension meter! is used, fencers can only! guess at the tension. If they! have been used to working! with No. 8 wire, the tend-1 ency will be to overstrain | 12} gauge. This must not| occur.

Barbed wire is very costly, and often unnecessary. In some cases there is a place for it, especially where stock pressures on a fence are severe. However, the alternative of running a plain, electrified, mainsoperated 12} gauge wire should be investigated. It is often cheaper, and just as effective.

Materials vary in price between one district and another —so does cartage. The costs estimated below are for hill country development within 50 miles of the nearest railhead. The fences chosen are typical of those currently being constructed, and provide a reasonable basis for comparison. “Standard Fence”— 7 No. 8 gauge wires plus one 3in by 12} gauge barb, 3 posts per chain, 2 Waratahs between posts. Materials only cost SIOOO per mile. Labour $450 to SSOO per mile. “8 Wire fence”—B. 12} gauge wires, 3 posts per chain, 4 battens between posts. Materials only SBOO per mile. Labour S4OO to $450 per mile. “8 Line 36in high, 12in stay High Tensile Netting” —4 posts per chain, 4 Waratahs per chain. Materials

only, SBOO per mile. Labour $375 to $425 per mile. “Soil Con”—10 wire, 12J gauge, 4 posts per chain, 4 battens per chain. Materials only, S6OO per mile. Labour, S4OO to $450 per mile. The labour charge for fences is often difficult to assess. The majority of fences are erected with farm labour at no extra cost.

Most contractors drive posts—either by hand or with the aid of a machine. Most merchants provide pointed posts for driving. These should not be sharpened to a fine point but should have a semi-blunt end. Otherwise the posts will be difficult to drive in straight.

There are many laboursaving devices on the market at present that can take some of the hard, strenuous work out of fencing. Often the legal aspect of fencing is questioned. This can be summed up by the statement that legally, as long as both parties agree, any fence can be erected to serve as a boundary. However, you must always remember that you not only want to keep your stock in, but that the neighbour’s must be kept out.

The accompanying item on fencing has been prepared by D. M. Cross, farm advisory officer tagricultural engineering), Department of Agriculture, Blenheim.