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LINKS FIXED: FIXED nailing

SHEET LESSON 1

nailing nailing is a process that allows you to combine elements in a stable and definitively by the use of nails.
The operation is to drill holes on the elements to connect, which will be tucked inside the nails; the connection is made by riveting stem protruding.
The riveting can be done either hot or cold. The process of riveting, hard-working technology is so expensive, is made in cases where welding create structural problems (lack of heat treatments on weldment).
The nails can be of three types.
The nails strength and sealing are carried out on containers (high-pressure tanks, boilers, autoclave-vi, penstocks), whose mission is to support and considerable efforts to ensure a tight seal. The rivets holding
are required to ensure that the seal in the presence of small efforts (low-pressure tanks, gas holder, fireplaces).
The riveting force run when you need to fix problems without considerable effort required (metal construction carpentry, trellises, sheds, decks).

The nail is a mechanical device consisting of two basic parts: the head and stem .
The head is available in the forms provided by the unification-ment and the truncated conical shank is protruding with respect to the elements to merge, a part intended to be riba-fingers (hot or cold) to form the other head.

Fig.1.1 nail before and after the riveting

The nails are divided into:
nails (proper) and when the stem has the diameter greater than 8 mm; Ormala are hot riveted.
rivets (or rivets), when the stem has a diameter less than 8 mm are repeated cold.

Head size and head shapes characterize the different types of nails in Table F3.1 with its fo-ri preparation, to be achieved on the elements that combine in the head and hand riveting.
Stem The stem is a truncated cone (taper 1:50) to facilitate its introduction into the holes. The riveting hot nail generates compression between the two heads of the elements to be joined, and this effect is then enhanced by the contraction of the stem during cooling. Therefore, the nails are not only encouraged to cut, but also traction along their axis and the joint efforts between the two transmit elements by friction. The
UNI tables provide for the nails the following tri-diameter, expressed in mm:
8 - 10 - 13 to 16 - 19 - 22 to 25 - 28 - 31 - 34 - 37 to 40
Material Nails are made of steel extra sweet, with ele-vated capacity of plastic deformation (elongation at fracture of 25%).
is important, however, that the material is fragile or hardenable. For this reason we also use copper nails, brass or light alloy.
Forum The hole diameter is slightly larger (from 0.5 to 1 mm) of the shank of the nail. The hole on the elements that unite can be achieved by punching or drilling. Punching is cheaper because it faster, but it can damage the material deforming the contour of the hole. The drilling, coupled with the bevel of the edges, it is essential for holding nails.
Forms nailing The union of two elements can be made by nailing in the following ways, each of which has its own practical formulas for sizing:
nailing
simple overlap - with a row of nails (fig. F 1.2)
- with two rows of nails facing (F 1.3)
- with two rows of nails staggered nailing a simple joint cover (slightly used)
- with a row of nails
- with two rows of nails staggered.

Fig. 1.2 nailing with a single row of nails

Fig. 1.3 nailing single with two rows of nails

Designation of nails
The designation of the nails include:
- the word nail (not compulsory)
-
of the diameter - the length of the stem before
- the material.

example of designation of the nails
Chiodo 13 x 45 UNI 2514 - C10
nail countersunk head cap
reduced shank diameter d = 13 mm
stem length l = 45 mm
steel material C10.

Nails Special
In applications that require serial quick installation and require no great stretch of the ra-closing mechanics, special nails are used (see Table F3.1), such as nail slots Round head (UNI 7591) and slotted (UNI 7592) or nails High resistance button head and neck tightening, as projected by recent chart UNI 8646 (Fig. 1.4)

Fig . 1.4 Nail Special with adjustable collar

The implementation stages of the nail with clamping hub are:
1) is part of the nail holes of the elements to join
2) pulls on his collar sticking out part Stem
3) you put tension on the nail, holding it by the tail with a special tool
4) it presses and deforms the collar up to engage the grooves heating sal-tightening
5) tears of the tail wheel, causing the breaking-ra in correspondence with the groove

Rivets Rivets are nails shank diameter normally less than 8 mm, still riveted cold. The riveting
cold generates compression between the two heads of the elements to merge. Compared with nails missing, in this case, the contribution to the compression due to contraction of the stem. UNI
tables provide the following for rivets diameter, in millimeters:
0,8-1-1,2-1,4-1,7-2-2,3 - 2.6 - 3 - 3, 5 - 4 - 5 to 8
The material they are made rivets can be mild steel, aluminum, copper, brass, alloys leg-gere. Some rivets lead in a head-ment contracted specification of the material (Fig. 1.5),
The description of the rivets is performed with the same information already described for the nails.
widely used, even if not unified, are ribat-tini expansion. They have the prerogative to be able to be realized between the closure elements that do not allow access to the stem from stress, but that is retracted using different techniques (Fig. 1.6)