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Customer requirements for male inserts have
proved to be so varied it is difficult to stock a ‘standard'
range of inserts. Tappex have therefore decided to treat every
application as in effect, a special male fastener, to meet
the designer's specific needs.
Where possible we will offer the closest existing
insert as an alternative, to eliminate the need for special
manufacture and hence reduce costs and lead-time.
The head profile of a Tappex male insert would
normally take the form of the Trisert, Multisert, or Hi-mould.
The male thread required defines the head end size, that is
the same as the female version of the same thread. Details
of the head end dimensions may be taken from the equivalent
female product pages on this web site.
The coding for a Tappex male insert always commences
with the number 5 and is followed by the part number for the
equivalent profile found in the range of female inserts. (The
number 5 replaces the first digit of the female part number).
Product Features
Each of the male inserts retains the basic design
and installation features of the female version. Headed, Unheaded,
Short, Regular and Long can all be produced.
Definitions
- Head End - The profile of the fastening end of the male
insert that is fixed into the parent material.
- Head Length - Normally the overall length of the equivalent
female fastener.
- Overall Male Thread Length - The overall length of the
male insert less the head length. This may incorporate special
ends to the thread to assist in location of the nut or other
customer design requirements.
- Plain Portion - There is a run out between the commencement
of the thread and the shoulder of the head profile, which
is generally restricted in length.
- Nut End Length (NEL) - This defines the maximum distance
from the commencement of the chamfer at the end of the thread
to the head profile and incorporates the plain portion.
Design
Aids
Providing the application is suitable, for a
post installation, male versions of the Multisert design,
used as push in inserts, are the quickest to install and most
economic. If higher pull out performance were required then
a male based on the Trisert design would be preferable.
For the optimum performance a male insert based
on the HiMould design, moulded into the parent material, should
be used.
Having decided on the most suitable method of
installation and therefore head end design, the overall male
thread length and nut end length (if different) should be
defined.
Generally the length of the plain portion is
2.5 times the thread pitch for nut end lengths of four times
the thread diameter or less, or four times the thread pitch
for nut end lengths greater than four times the thread diameter.
In practise these are gauged with 6g thread ring gauges and
generally a minimum of half a thread pitch can be deducted
from the plain portion length when using standard nuts.
The diameter of the plain portion will never
be greater than the thread diameter plus 0.2mm and never less
than the maximum effective diameter.
Where customers require the fixing of a relatively
thick mating component, there is no need for the thread to
extend the whole length of the insert. An excessively long
thread length can weaken the fixing due to the thread stretching
under the tightened nut.
Hole Designs
The hole designs for the equivalent female will
apply.
Heat installation of male Multiserts should
generally be avoided due to the extra time required to heat
them up and movement afterward, as they then take longer to
cool down acting as a heat sink.
Certain materials or thin walls may still necessitate
their use in this way. If the insert is to be installed into
a blind hole, air may be trapped beneath the insert becoming
compressed and reacting against the downward pressure pushing
the insert back out of the hole. In this situation a 1mm key
way should be introduced 0.8 times the head end length.
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profile
sample/quotation