Free Delivery on all orders over £99*

A4 Arbor with 6.3mm HSS Pilot Drill Bit - 9.5mm Hex Shank

£299
The RRP is the manufacturer's recommended retail price of the item.
Limited Stock
We are an Independent UK Company
Price match. Found it cheaper? Contact us
Trade Discount Available
Description

The Knightsbridge A4 arbor is a holesaw mandrel with an integrated 6.3mm high-speed steel pilot drill bit and a 9.5mm hex shank for drill chuck mounting. The arbor allows Knightsbridge holesaws in the 20-25mm diameter range to be driven by standard cordless or corded drills, with the pilot bit centring the holesaw before the teeth engage the material.

Designed for electricians and tradespeople cutting knockout holes for cables, switches and downlights in plasterboard, softwood and MDF, the arbor suits repetitive installation work where multiple holes need centring accurately. The hex shank prevents slippage in keyless drill chucks under torque, and the 91mm overall length gives clearance to cut through standard 12.5mm plasterboard with 50mm ceiling battens behind.

The arbor body is machined steel with a black oxide finish to reduce corrosion from on-site moisture and sweat contact. The 6.3mm pilot bit is high-speed steel rather than carbide, meaning it drills cleanly through softwood and plasterboard but should not be used on masonry, tile or hardened steel. The arbor fits Knightsbridge holesaws HS20MM, HS22MM and HS25MM via a threaded collar that locks the holesaw to the arbor shank.

Specification
Diameter 19 mm
Length 91.3 mm
Construction Steel
Finish Black
Warranty 0
Downloads

Product Specification Sheet

Frequently Asked

Which Knightsbridge holesaws does this arbor fit?

The A4 arbor is compatible with Knightsbridge holesaws HS20MM, HS22MM and HS25MM. The holesaw threads onto the arbor shank via a locking collar. It does not fit larger diameter holesaws in the Knightsbridge range.

What materials can the pilot bit drill through?

The 6.3mm high-speed steel pilot bit drills cleanly through plasterboard, softwood, MDF and PVC. It is not suitable for masonry, tile, hardened steel or metal conduit, where a carbide-tipped pilot bit would be required.

Will the hex shank fit all drill chucks?

The 9.5mm hex shank fits standard keyless drill chucks on cordless and corded drills. The hex profile prevents the arbor spinning under torque when the holesaw engages thicker material. Older keyed chucks may also accept the hex shank depending on jaw design.

Can the pilot bit be replaced if it dulls?

The pilot bit is integrated into the arbor body and cannot be replaced separately. Once the bit dulls from extended use, the entire arbor would need replacing. Regularly clearing swarf from the bit flutes extends working life.

Shipping & Returns

Delivery UK delivery is £14.99, and delivery is free on all orders of £99 or more, in the UK and internationally.

Returns If you change your mind, you have 14 days from delivery to tell us, and a further 14 days to send the goods back. Return postage for a change-of-mind return is paid by you. Change-of-mind returns are subject to an inspection and handling deduction. See our full returns policy.

To arrange a return, call us on 020 8149 5199 or use our contact page.

See it lit, in person

Lighting looks different in a real room. Come and see our range at our showrooms in Birmingham, Hong Kong and Dubai, or talk to our design team wherever you are.

Niori lighting showroom trailer video with closeups of alabaster lighting

Why Niori

Over 20 years lighting homes worldwide

We are a specialist lighting and mirror retailer with showrooms in Birmingham, Hong Kong and Dubai, shipping to customers around the world. Our own design team is here to help, from first idea to final fitting.

Genuine products

An authorised stockist

Every product arrives brand new with the full manufacturer warranty. Found it cheaper elsewhere? Ask us about a price match.

Ordering with us

Free delivery over £99

Free delivery on orders over £99, in the UK and worldwide. Easy returns within 14 days, subject to our returns policy. Full manufacturer warranty included.

Design help

Not sure what you need?

Our design team can help you plan your lighting, share photos and videos of stock, and send samples worldwide. Book a showroom visit in Birmingham, Hong Kong or Dubai, or ask about our lighting design service.

You Might Also Like

Recommended For You

    Our Reviews

    From first click to final installation, our customers share how Niori lights up their spaces. Read their words and envision what’s possible for yours.

    Featured Projects

    Step into our portfolio and see how we transform homes, restaurants, and commercial spaces and more, worldwide. Click here for a closer look at our latest projects.

    Description

    The Knightsbridge A4 arbor is a holesaw mandrel with an integrated 6.3mm high-speed steel pilot drill bit and a 9.5mm hex shank for drill chuck mounting. The arbor allows Knightsbridge holesaws in the 20-25mm diameter range to be driven by standard cordless or corded drills, with the pilot bit centring the holesaw before the teeth engage the material.

    Designed for electricians and tradespeople cutting knockout holes for cables, switches and downlights in plasterboard, softwood and MDF, the arbor suits repetitive installation work where multiple holes need centring accurately. The hex shank prevents slippage in keyless drill chucks under torque, and the 91mm overall length gives clearance to cut through standard 12.5mm plasterboard with 50mm ceiling battens behind.

    The arbor body is machined steel with a black oxide finish to reduce corrosion from on-site moisture and sweat contact. The 6.3mm pilot bit is high-speed steel rather than carbide, meaning it drills cleanly through softwood and plasterboard but should not be used on masonry, tile or hardened steel. The arbor fits Knightsbridge holesaws HS20MM, HS22MM and HS25MM via a threaded collar that locks the holesaw to the arbor shank.

    Specification
    Diameter 19 mm
    Length 91.3 mm
    Construction Steel
    Finish Black
    Warranty 0
    Downloads

    Product Specification Sheet

    Frequently Asked

    Which Knightsbridge holesaws does this arbor fit?

    The A4 arbor is compatible with Knightsbridge holesaws HS20MM, HS22MM and HS25MM. The holesaw threads onto the arbor shank via a locking collar. It does not fit larger diameter holesaws in the Knightsbridge range.

    What materials can the pilot bit drill through?

    The 6.3mm high-speed steel pilot bit drills cleanly through plasterboard, softwood, MDF and PVC. It is not suitable for masonry, tile, hardened steel or metal conduit, where a carbide-tipped pilot bit would be required.

    Will the hex shank fit all drill chucks?

    The 9.5mm hex shank fits standard keyless drill chucks on cordless and corded drills. The hex profile prevents the arbor spinning under torque when the holesaw engages thicker material. Older keyed chucks may also accept the hex shank depending on jaw design.

    Can the pilot bit be replaced if it dulls?

    The pilot bit is integrated into the arbor body and cannot be replaced separately. Once the bit dulls from extended use, the entire arbor would need replacing. Regularly clearing swarf from the bit flutes extends working life.

    Shipping & Returns

    Delivery UK delivery is £14.99, and delivery is free on all orders of £99 or more, in the UK and internationally.

    Returns If you change your mind, you have 14 days from delivery to tell us, and a further 14 days to send the goods back. Return postage for a change-of-mind return is paid by you. Change-of-mind returns are subject to an inspection and handling deduction. See our full returns policy.

    To arrange a return, call us on 020 8149 5199 or use our contact page.