There are different types of screws and bolts, each with a specific purpose (remember: a bolt is a screw + a nut).

Before choosing which fence screw is the best, you must consider the following 5 criteria:

  • Material for inserting the screw;
  • The thickness and strength of the support;
  • The thickness and weight of the load to be supported;
  • The screw material – preferably stainless steel outside;
  • Possible limitations of shock and distortion, mainly in terms of mechanics.

In general, consider that the greater the diameter of the screw, the greater its resistance to tearing and deformation. The same applies to its length: the longer it is, the more resistant it is to the force applied.

A screw is defined by different technical characteristics that determine its type:

  • Head shape: three types of heads are possible;
  • Type of pitch – Thread, mainly for metal and wood;
  • Diameter – in millimetres;
  • Length – in millimetres, with round, flat heads starting under the head and flared heads starting above the head;
  • Probably grafts and materials.

Screw heads: types and names

The screw heads can be:

  • Countersunk mouth, for soft materials, as the head enters during tightening;
  • Round, the head remains on the surface (screws for wood and metal);
  • Flat, the head has no graft for tightening with a screwdriver, but a wrench and always stays on the surface.

To better understand the name of a given screw, let’s take the HM10-60 screw as an example:

  • H: Indicates that the head is hexagonal;
  • M: indicates that the pitch is ISO metric (mechanical);
  • 10: Indicates that the screw diameter is 10 mm;
  • 60: The length of the screw is 60 mm (under the head).

Fencing screws: which one to choose?

If the fence is made of wood, surely this type has the property of screwing without preparing holes. They are pointed and threaded along their entire length to avoid damaging the wood during tightening. They have a flared head with Posidriv or Torx and are bichromate (yellow screw), stainless steel or galvanized (silver).

Threaded for half their length, cross-headed or shear-headed (flat coupling) and galvanized or stainless, wood screws are generally small diameters and small lengths.

If the fence is made of metal, you need an ad hoc screw. This type combines the largest number of shapes, lengths, diameters, head types and different steps. Usually, the properties of metal screws are calculated by the maker or manufacturer based on the equipment or machine in which they are installed. The material of a metal screw is very important in mechanical use as it determines the resistance to deformation, tearing, twisting, temperature and pressure of any kind that the screw can withstand. If you need to replace one or both of the machine screws, choose the same exact type: the value is written on the header.

What are the advantages of a Deter Bolt® Free screw?

DETER BOLT® FREE provides real anti-theft protection of the systems and therefore of the entire investment.

DETER BOLT® FREE guarantees:

  • Impossibility of removing the screw thanks to the spherical surface and the special notches, which cannot be gripped except with the key supplied.
  • Real anti-theft protection of the system and therefore of the entire investment.
  • Easy assembly due to the use of normal clutch and impact screwdrivers.
  • This reduces annual maintenance costs (normally calculated at around 1.5% of the total investment).
  • Significant savings on assembly time compared to normal anti-theft systems on the market, which results in a significant reduction in labor costs.
  • Possibility of carrying out regular maintenance or replacement of the panels without the need to break or tamper with the support structure.
  • Reduced assembly times compared to normal anti-theft systems on the market.
  • Possibility of implementation in all security projects.
  • No need to break or tamper with the support structure.
  • Consequent reduction of extraordinary maintenance costs (normally valued at 10% of the value of the system every 10/15 years).

DETER BOLT® FREE is reserved for all customers with low consumption, ranging between 500 and 5,000 pieces.

The features of the Deter Bolt® Free

The head of the screws maintains the carved and patented sphere that prevents it from being unscrewed in any way except with its specific key. The lower part of the flange has been produced with knurling designed to increase its tightness, thereby avoiding the use of washers and eliminating screw-washer costs and assembly times.

The DETER BOLT® Screw is designed to fit into any type of zeta or omega bracket at the edges of solar or photovoltaic panels, and it will be secured into it perfectly by applying a normal tightening force (15N/m).

The size is standard M8 with different lengths: from 20 to 50 mm fully threaded. It is made of AISI 304 cold-formed stainless steel.

The importance and effectiveness of the DETER BOLT® system is due to the use of special keys for screwing and unscrewing.

Illegal key reproduction involves heavy investments, as if they are not made with high-quality materials with well-defined technical specifications and are not perfectly identical in the shape of the screw head it is not possible to unscrew them.