Self Tapping Thread Repair Kits
Pear Tree Engineering

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Thin Wall Self-tapping Inserts Tappex

Installation Procedure

Ensat Emerging
  1. Drill hole to correct diameter, countersink if necessary.
  2. Screw the Ensat onto the driving tool with the cutting slot or cutting hole pointing downwards.
  3. Ensure that driving stud engagement into the Ensat does not exceed half the height of the cutting slot or hole
  4. Ensure that the insertion tool and Ensat are perpendicular to the hole.
  5. When using a production driver, the rotating shell must rest against the externally visible stop pins in such a way that it is driven round clockwise by the pins.
  6. Set depth control, where applicable, to 0.1/0.2mm below the surface of the receiving material.
  7. Apply reasonable downward pressure whilst driving the Ensat into the material to 0.1/0.2mm below the surface.
  8. Finally back the driving tool out of the Ensat. In the case of a production driver the friction lock will be released automatically, the hand tool will require the hexagon nut to be held as the drive is reversed.

Avoid "bottoming" the insert or using excessive torque as this may strip the insert out or reduce pull-out loading.

Most insertion problems arise from incorrect hole size, poor tool maintenance or bad insertion techniques. Adequate trials should always be carried out before moving to production.

Samples and low volume applications

A hand tool is available for use with a tap wrench.

For field repair or initial tests, a nut and bolt can be used. Ensure best possible alignment of the insert in relation to the hole.

Hole size calculation

Whilst 30% thread engagement will normally give almost maximum performance, the most appropriate hole size will vary according to the type of receiving material and the type of insert to be used.

Example: Hole size for light alloy with tensile strength of 280 N/mm2 for M8 insert type 302 is 10.8 - 11.0mm, for M8 insert type 307 is 11.1 - 11.2mm.
If difficulty is experienced in installation, it is possible to take the next hole size up without a detrimental effect. However, this should always be established by tests prior to production.

External Thread Interference

For a work-piece made of a light alloy, this diagram illustrates clearly that whilst correct hole sizes are important for product reliability, the Ensat 302 achieves almost maximum pull-out with only 30% external thread interference.

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