TRS-35?
The aim is to achieve the best possible pull-out resistance. This is achieved by the fact that the embedment depth of the main screw embeds as much as possible. The problem with the supplied standard screws is that they are usually too short. There can be many reasons for this, but in particular the strength of the ATW, foot straps and also deck pads differ, so that the screw is more or less deeply integrated depending on the make selected. The pull-out resistance can be reduced by up to 25% if the screws are too short!
What is different about the TRS-35?
The TRS-35 are 35mm long and come with 3 pieces of 1.6mm thick polyamide washers. The length of the screw can be adjusted between 30-35mm. The following picture shows a perfectly adjusted screw length (without washers).
Important:
Screws that are too short: increased risk of overtightening / tearing out the inserts
Screws too long: The screw tip is touching the bottom. If you continue to turn the insert or the screw, you can overtighten!
Therefore, always choose the perfect screw length!
How do I set the correct screw length?
1. Measure the hole depth of the inserts
The holes must be free of sand, dirt or other impurities! Impurities in the insert hole reduce the possible depth of the screw and can result in the screw being over-tightened!
Standard inserts are approx. 20mm deep. Measure independently!
2. Test screw connection
Use your standard screws, these should be around 28-32mm long or use the TRS-35 with all 3-polyamide washers and install one side of the foot strap. Then measure the protrusion between the pin (ATW) and the upper edge (CAP) as shown in the following picture.
3. Determine the embedment depth
Take another ATW with a cover cap and the same screw and set the protrusion measured before. Now measure the protrusion from the screw tip to the lower edge of the ATW.
Formula: measured overhang + compressed deck pad – safety distance = Embedment depth
Example: 15mm (measured) + 2 mm (cover pad) – 2mm (security) = 15 mm (embedment depth)
4. Determine the maximum screw length
Formula: insert depth – embedment depth + screw length = max. Screw length
e.g.: 20 mm (insert) – 15 mm (embedment depth) + 30mm (screw length) = 35 mm (max. screw length)
Note
If there are foreign bodies in the insert hole, this reduces the insert depth. This can lead to over-tightening the screws or inserts! The same applies to screws that are set too long. If the screws are too short, there is again the risk that the insert hole will be overtightened or the screw will tear out!