M10 x 25 Square head bolt

Description

This Schletter M10 x 25 Square Head Bolt is a stainless steel fastener used within Schletter's Classic and ProLine mounting rail systems, and with FixZ support profiles, where the square head sits securely inside the rail's screw channel without rotating during tightening.

Manufactured in A2 (304-grade) stainless steel with full thread along its 21mm effective length, it is designed to give a strong, corrosion-resistant clamping connection between rail components and support hardware.

M10 x 25

Thread & Length

17mm

Wrench Size (A/F)

21mm

Thread Length

A2 Stainless

Material Grade

Full Thread

Thread Coverage

Square Head

Head Type

Key Features

Anti-Rotation Square Head

The square head design locates inside the rail's screw channel and resists rotation while the opposite fastener is tightened, speeding up single-person installation.

Full-Length Thread

Threaded along its full 21mm effective length, giving maximum engagement when clamping components together.

Corrosion-Resistant A2 Stainless Steel

Manufactured from A2 (304) stainless steel, suited to long-term outdoor exposure across UK weather conditions.

Compatible With Classic & ProLine Rails

Designed for use with Schletter's Classic and ProLine rail profiles, as well as FixZ support profiles, for consistent fastening across the wider mounting system.

17mm Wrench Size

Tightened with a standard 17mm spanner or socket, keeping tooling requirements simple and consistent with other Schletter M10 hardware.

No Flange, Nut or Washer Included

Supplied as the bolt only; pair with the appropriate flange nut and washer per your specific rail connection detail.

Technical Specification

Bolt Specification

Thread Size

M10

Length (under head)

25 mm

Thread Length

21 mm

Full Thread

Yes

Head Shape

Square

Head Height

6 mm

Wrench Size (Across Flats)

17 mm

Thread Pitch

1.5 mm

Left-Hand Thread

No

Materials

Material

Stainless steel, grade 304 (1.4301) – A2

Surface Protection

Untreated

Includes Flange, Nut or Washer

No

Compatibility

Compatible Systems

Schletter Classic profile, ProLine profile, FixZ support profiles

Frequently Asked Questions

What rail systems is this bolt used with?

It is used within Schletter's Classic and ProLine mounting rail ranges, and can be combined with FixZ support profiles.

Why does this bolt have a square head instead of hexagon?

The square head locates securely inside the rail's internal screw channel and resists rotation while the nut on the opposite side is tightened, making single-handed fitting easier on site.

What size spanner do I need for the nut side?

A 17mm wrench or socket is used on the matching nut; the square head itself sits captive in the rail channel and does not need to be turned.

Is this bolt sold with a nut or washer?

No, this listing is for the bolt only. Pair it with an appropriate M10 nut, such as Schletter's serrated M10 flange nut, depending on the specific connection you are making.

Is A2 stainless steel suitable for permanent outdoor use?

Yes, A2 (304-grade) stainless steel offers good general corrosion resistance and is a standard material choice for outdoor PV mounting hardware in the UK climate.

BTU Calculator

BTU & WATT Calculator

Room Dimensions

Length (in m):

Width (in m):

Height (in m):

Room Type

Living Room

Bedroom

Kitchen

Bathroom

Conservatory

Hallway

Glazing Type

Single Glazed

Double Glazed

Triple Glazed

External Walls

0 Wall

1 Wall

2 Walls

3 Walls

4 Walls

Insulation Level

Poor

Average

Good (New Build)

Calculate

Required Heating

0

Watts

0

BTUs