Diamond Core Drill Bit 1 3/8 in (35mm) 2pcs - Fast Smooth Holes

In this review we test the BRSCHNITT 1 3/8 in (35mm) diamond core drill bit two-pack to see who will get the most value from it. The bottom line: this set is for DIYers and tradespeople who need a compact core bit that cuts fast through granite, marble and masonry, with the single biggest reason to buy being the clean, stable cutting produced by the laser welded diamond segments and 10mm diamond height. It offers a straightforward replacement option for angle grinder-mounted core work where small, precise holes are required.

Key Features

• Size and fit: Each pack includes two 1 3/8 in (35mm) core bits with a 5/8-11 thread, making them compatible with common angle grinder arbors and many core drilling adapters.
• Segment design: The 10mm diamond height and #25/35 grit provide a balance of material removal and edge control for cutting through hard stone and concrete without excessive chipping.
• Build quality: Laser welded segments with a vacuum brazing protective layer help prevent segment loss and keep the steel core protected for cleaner cuts over time.
• Dry or wet use: The bits work well for dry drilling, but using water for cooling can significantly extend segment life when cutting thick granite or prolonged runs.
• Working length: An 80mm working length and 100mm total length give enough depth for common countertop and block applications while remaining compact for handheld use.

Who It's For

This diamond core drill bit set is best for homeowners doing countertop cutouts, tile installers, and builders who need a small-diameter core for plumbing or fixture holes in granite, marble, or masonry. The 35mm size matches many common fixture and anchor needs and the 5/8-11 thread fits standard angle grinder adapters.

It is less suitable for heavy daily production work where long runs and constant deep cuts are required; contractors who need high throughputs or larger diameters should opt for industrial core systems and wet drilling rigs designed for continuous use.

Pros & Cons

Pros

• Laser welded segments and vacuum brazing produce clean cuts and reduce the chance of segment separation during typical jobs.
• Suitable for dry drilling in many materials, with water as an option to prolong lifetime on thick stone.
• Compact 35mm size and 5/8-11 thread make it easy to fit to common angle grinder setups for precise holes.

Cons

• Mixed user reports on durability suggest performance can vary with application and technique, so longevity may be inconsistent for heavy or improper use.

Specifications

Pack	2 pieces
Diameter	1 3/8 in (35mm)
Diamond height	10mm
Total length	100mm
Working length	80mm
Grit	#25/35
Thread	5/8-11

Our Verdict

The 1 3/8 in diamond core bit two-pack is a practical, value-focused choice for DIYers and tradespeople needing precise, small-diameter holes in granite, marble and masonry. Its laser welded segments and protective brazing deliver stable, clean drilling, and performance improves noticeably when water cooling is used. Those doing heavy production work should consider heavier duty cores, but for occasional to moderate jobs this set represents sensible value.

Frequently Asked Questions

Can these bits be used wet?
Yes, they can be used wet and adding water during thick granite drilling will help cool the bits and extend their life.

What machines are compatible?
They are intended for use with an angle grinder fitted with a 5/8-11 arbor or compatible core drill adapter.

Are they suitable for reinforced concrete?
They can cut reinforced concrete and block, but progress depends on reinforcement density and correct use; cooling and light pressure improve results.