Technical Support

We often hear from customers that the wire inserts they’ve received from us are shorter than what was ordered. However, it’s a little-known fact that inserts cannot be measured in their free state, as they expand to their true length when installed. This can be a little confusing, so one way to check you have the right size is to count the number of coils on the insert.

Please use our product selector tool to find out how many coils your particular size of insert should have, found under the ‘NC’ column in the results table:

Wire Insert Product Selector

Throughout the fastener and engineering industries, the term ‘Helicoil’ has become synonymous with wire thread inserts, in the same way that ‘hoover’ has become the common name for vacuum cleaners and 'photoshop' is now a general term for image editing. There are many brands that offer wire thread inserts manufactured to equivalent technical specifications, including our own inserts, which we manufacture in accordance with national and international industry standards. However, if you do need a particular alternative brand of wire insert, we are also able to quote on Helicoil® and Recoil®, though minimums may apply for their products.

Speak to our sales team today for a quotation

Sometimes customers require inserts to be dyed red, green, or blue. The dye does not affect the inserts’ performance or installation process, and is simply used as a means of identifying between different types of inserts – typically free running inserts are green dyed and screw locking inserts are red dyed.

However, we know many people don’t need their wire inserts dyed, and that’s why we stock our inserts in natural finish and have the capacity to colour coat inserts on-site as per your order requirements. Minimums may apply for this service.

Get in touch to discuss your requirements

We don’t supply certification with our wire inserts unless it is requested by customers, as for most industries it is not required. However, for the ones that do need that extra level of security and traceability, we can provide Certificates of Conformity, Material Certificates, FAIRs, ISIRs, and PPAP reports in accordance with our aerospace registration. Charges apply for these and they must be requested at the time of order, as we cannot issue this documentation retrospectively.

In its raw condition, stainless steel is not magnetic, but the insert manufacturing process induces a slight magnetic trace. This degree of induced magnetism is of a minimal level and in most general applications will not affect performance. If, however, non-magnetic inserts are a critical requirement for your application, we would recommend using phosphor bronze or Inconel inserts as an alternative to stainless steel.

Find out more about available alternative materials

All manufactured engineering components have tolerances, and threads themselves have measurable tolerances called fit classification. British Standard threads are simply called close, medium, and open, whereas Unified threads are termed as 3B (close fit), 2B (medium fit), and 1B (open fit), and Metric threads are termed as 4H (close fit), 5H (medium fit), and 6H (open fit). UNJ and MJ threads only have close fit tolerances (3B and 4H, respectively).

J thread (MJ, UNJ) is only specified for use in aerospace applications. It has an increased root radius that is designed to be stronger at the root of the thread (the weakest point) when compared to standard UN and metric threads.

Our wire inserts are manufactured from fully certified aerospace material and are suitable for use with both conventional and controlled root radius threads, so they can be used with both standard UN/metric bolts and screws, as well as UNJ/MJ ones e.g. our metric threads meet both MJ threads to BS6293 and standard M form threads to BS3643.

A common misunderstanding is that a tap sized larger than the insert diameter is required to tap the correct size hole (e.g. an M16 tap needed for M14 inserts). In order to clear up this confusion and make things as straightforward as possible, our wire insert taps are specially manufactured to be slightly oversize to accommodate the wire insert – so for M14 inserts, you will simply need an M14 wire insert tap.

Our wire inserts are manufactured from fully certified aerospace grade materials. We only purchase raw materials from fully approved manufacturers that hold, as a minimum requirement, ISO 9001:2015 approval. We also reassess our suppliers annually to ensure their approvals are maintained.

All iron and steel products as listed in Annex XVII of Council Regulation (EU) 2022/2474 amending Regulation (EU) No 833/2014 and Schedule 3B of Russia (Sanctions) (EU Exit) (Amendment) Regulations 2023 that are sold or otherwise supplied by WTI Fasteners Ltd do not originate from and have not been exported from Russia. Likewise, such products do not incorporate any iron and steel products (as defined in Annex XVII and Schedule 3B) that originate in Russia when having been processed in a third country.

There are six basic stages for installing wire thread inserts:

1. Depending upon your application, either drill a new hole, or drill out the damaged thread.
2. Tap thread in the hole using a wire insert tap. A standard tap will not provide the correct thread.
3. Check the tapped hole using a wire insert gauge.
4. Use your tool of choice to install the insert into the hole. Wind the insert until it is positioned approximately 1/4 to 1/2 a pitch below the surface.
5. Use a tang break tool or a plain pin punch to break off the tang. Remove the loose tang from the hole.
6. Check the installed insert using a thread plug gauge.

Please refer to the product pages for further instructions on how to use the different types of tooling.