Tappex Multisert
Tappex Multisert
Tappex Multisert

Threaded inserts for Engineering plastics

The Tappex Multisert® range of brass thread inserts for plastics has been developed to be a multi-purpose insert for a wide variety of industry applications; range includes four primary designs: Unheaded, Single Thickness Headed (at standard & reduced diameters) & Double Thickness Head.  Lengths normally stated in mm.

Multisert® – Unheaded – Product Features

The most significant feature of the Mulitisert is its barb form that makes the insert suitable for different installation methods. The designer can therefore increase pull-out performance using the same insert by changing from press-fitting cold to heat or even ultrasonic insertion.

External barb form gives good flow characteristics and high pull-out performance.

Plain top ring gives a good bearing surface for mating components and traps any molten plastic forced upwards during insertion providing a clean flush fit (correct hole size must be used).

Free running internal thread – the insert is set in the plastic independently from the expansion action of the mating screw. This prevents rotation or screw breakage during assembly.

Plain location spigot and pilot barb ensures that the insert locates squarely in the drilled or moulded hole prior to assembly.

Multisert® – Unheaded – Design Aids

  • It should be specified for press-in applications in flexible thermoplastics, installation can be adjacent to the moulding machine for operation efficiency
  • It can be installed into most thermoplastics by heat or ultrasonics to give higher resistance to pull out loads
  • It should be specified for small or medium volume usage where there are a limited number of inserts per moulding
  • It should be specified for high volume, single insert applications, in small mouldings
  • It is available in two standard lengths to maximise choice, the barb form design makes it possible to manufacture non-standard lengths if customer applications cannot accommodate standard lengths
  • To obtain maximum performance from the insert, the hole diameter in the mating part should be clearance for the screw thread-only. The mating part will then support the top face of the insert which , in turn, reduces the possibility of rotation or ‘jack-out’ during final assembly
  • It can be used as a pull-through insert where access to the rear of the plastic component is possible;  recommended only where a stepped hole design is used as illustrated

Multisert® – Single Thickness Head – Product Features

The Single Thickness Headed version of the Multisert incorporates all the standard features of the unheaded version but provides the designer and production engineer with three standard options to match product availability to common assembly situations not suitable to an unheaded insert. Large Diameter Head prevents jack out in applications where elongated slots or larger than standard clearance holes are necessary in the mating component. It has a larger bearing surface that is required in high torque applications. Two standard head diameters are available to provide for both performance and cost priorities.

Multisert® – Single Thickness Head – Design Aids

  • It should be specified in applications where increased resistance to rotation is required. The insert can be installed by press-in or heat insertion; it is not recommended for ultrasonic insertion without consultation
  • It also provides an excellent conductive surface for electrical contacts, ring connectors or eyelets
  • All ‘Pull-through’ installations should be considered carefully and if in doubt please contact Tappex for more technical advice (this includes 071  & 072 variants)

Multisert® – Double Thickness Head – Product Features

The Double Thickness Headed version of the Multisert incorporates all the standard features of the unheaded insert but provides the designer and production engineer with a higher performance press-in insert for applications with through holes where access to the back of the component is possible.

Double Thickness Head can be used as a stand off or heat sink; it is possible to increase the head thickness still further, subject to quantities required.

Large Diameter Head for use in very soft materials where a smaller head diameter would pull through due to the flexing of the plastic.

Double Thickness Head – Design Aids

  • The reduced head diameter short length versions (part nos: 072 & 073) should normally be specified in compact plastic materials as they have the lowest unit cost but in most rigid materials give very high performance. Use of a stepped hole similar to that when using un-headed inserts in pull-through applications will, where space allows, increase performance
  • The regular length insert body (part nos: 005) should only be specified where there is a high push-out force prior to engagement of the screw
  • Normally press-fit insertion is acceptable except when the assembly is subject to heat, vibration, drop tests or the plastic is stress prone and unfilled – if in doubt call Tappex
  • All ‘Pull-through’ installations should be considered carefully and if in doubt please contact Tappex for more technical advice (this includes all 003 & 004 variants)
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Product Length


Material: Brass - to BS EN 12164 CW 614N
REACH/RoHS compliant as per the candidate list of substances of very high concern.

Finish: Self-Colour. Special finishes to customer requirements, at extra cost.

Description: The Multisert Unheaded is a barbed insert, and is available in two standard lengths - regular and short.

Application: Used in thermoplastic materials where mating component fits flush, or in controlled pull through applications providing correct stepped hole design is used, at lower unit cost than headed inserts. Also can be used in light load applications in timber.

Hole Size: Moulded and drilled hole diameters vary dependent upon the nature of the final assembly, component geometry and plastic material. Please consult our technical department for a precise recommendation, to ensure optimum production conditions.Sizes given are for reference purposes only.

Hole Design: The hole design information is intended to indicate the approximate dimensional requirements for satisfactory installation of the insert. They should not be specified for production tooling without prior consultation with our Application Engineering Department - we accept no responsibility should the use of this information without consultation result in product failure. Please call our application engineers for assistance +44 (0) 1789 206600

Installation: This insert can be press fitted cold, hot or with ultrasonics depending on the plastic material .

Insert Design

Multisert unheaded insert design
Part No.: 002M2
Thread Size: M2
Pitch (internal): 0.40
Length L: 3.10

Hole Design

Tappex Mutlisert hole design
Hole Diameter C: 3.0-3.3
Hole Depth Y: 3.20
Boss Diameter X: 6.00
Wall Thickness W: 1.35

The following are downloads relating to the Multisert®  range, although a download may also be applicable to other product ranges. General information can be found on our downloads page.

If you can’t find what you are looking for our helpful team are ready to assist you, simply give us a ring on +44 (0) 1789 206600.

Tappex Downloads - PDF

Tappex Performance data of Inserts for Plastics in generic applications.

Tappex Downloads - PDF

Tappex Performance data of Inserts for Plastics in generic applications.

Installing Multisert Brass Threaded Inserts Into Nylon Using The Tappex Heat Inserter Tool

In this video we demonstrate the ease at which Tappex’s Heat installer can be used to insert Tappex Multisert, Microbarb and Dedsert brass thread inserts into plastic.

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