Unite thread-forming type C
Thread-Forming Type C Screws for Roof Safety, Solar Panels and Light Section Steel
What our thread-forming type C range is built for
Our thread-forming type C screws are designed for fastening in light section steel and profiles where clean, dependable joining matters. This family is especially relevant for roof safety, solar panel mounting and similar steel-to-steel installations where the right drill-hole size and screw diameter matter from the start.
The range is intentionally focused rather than broad. It includes our stainless Marutex FC49M and FC61M standard options, plus the FC91 repair screw, so installers can stay within one clear product family when choosing for new fastening work or repair situations.
Choose within our thread-forming type C range
FC49M — 4.8 mm Type C screw
Choose our FC49M when you need the 4.8 mm option in this family for light section steel and profile connections. It suits the thinner part of the stated Type C application range and is also part of the family used for roof safety and solar panel mounting.
See dimensions and drill-hole guidance for FC49M on page 37 in the catalogue.
FC61M — 6.3 mm Type C screw
Choose our FC61M when the job calls for the 6.3 mm option within the same thread-forming Type C family. It is intended for pre-drilled light section steel and profiles across the stated substrate thickness range and keeps the specification aligned with the rest of the Type C system.
See dimensions and drill-hole guidance for FC61M on page 37 in the catalogue.
FC91 — repair screw
Choose our FC91 repair screw when the work calls for the repair-screw option in this family rather than the standard FC49M or FC61M screws. It keeps repair or correction work inside the same Type C page scope instead of forcing the project into a different screw family.
Detailed thread-forming type C data in our catalogue
Below, you can compare the core thread-forming Type C range in one place. The catalogue page brings together the standard screws, the repair screw and the practical drill-hole guidance that matters when you are joining light section steel correctly.
For this family, the most useful details to compare are diameter, stated steel thickness, bit/socket size and the recommended drill-hole diameter for the substrate range you are working with.
Need help choosing the right Type C screw?
We help contractors, installers and technical buyers choose the right thread-forming Type C solution for the actual job. If you are working with roof safety, solar panel mounting or other light section steel connections, we can help you narrow the choice before ordering.
That means quicker specification, fewer installation mistakes and better alignment between screw diameter, substrate thickness and whether the job needs a standard Type C screw or the repair screw.
How do I choose between FC49M and FC61M?
Choose based on the screw diameter and the substrate thickness range you are working with. In this family, FC49M is the 4.8 mm option and FC61M is the 6.3 mm option, so the correct choice depends on which part of the stated Type C thickness range your light section steel connection falls into.
When can thread-forming Type C screws be used without pre-drilling?
Within this family, the stated non-pre-drilled use is for 0.7 mm steel. For thicker light section steel and profile connections, the normal route is pre-drilled holes, so the installation should follow the stated drill-hole guidance instead of treating every substrate thickness the same way.
What drill-hole diameter should I use for thread-forming Type C screws?
It depends on both screw diameter and substrate thickness. The key point is that the drill-hole size changes across the Type C range, so the hole should be selected from the catalogue guidance for the exact screw and steel thickness you are using, rather than guessed on site.
When is the FC91 repair screw the right choice?
Use FC91 when the job specifically calls for the repair screw in the Type C family rather than the standard FC49M or FC61M options. That helps keep remedial fastening work within the same family logic instead of switching to a neighbouring screw page that is intended for another application.
Can Unite help us choose the right Type C screw for roof safety or solar panel mounting?
Yes. That is one of the clearest use cases for this family. We can help you match the Type C screw to the light section steel build-up, the need for pre-drilling and whether the project is better served by FC49M, FC61M or the FC91 repair screw.