Diamond drill bit Proxxon 28846 — diameter 3.8 cm, 1 piece

Proxxon 28846 is a single diamond drill bit with a 3.8 cm (38 mm) cutting wheel and a 3/32" (2.35 mm) shank, intended for precision drilling, cutting and shaping of very hard and brittle materials. The diamond-coated cutting surface delivers wear resistance and consistent performance when working with glass, porcelain, ceramics, composites and many hard plastics and non-ferrous metals. Cooling holes in the wheel reduce heat buildup during use to help avoid burn marks and extend tool life.

Advantages

The diamond grit on the wheel provides high abrasive strength and longer life compared with conventional bits on hard materials. Integrated cooling holes reduce temperature rise and minimize the risk of heat-related damage to the workpiece. The standard 3/32" (2.35 mm) shank fits common rotary tools and drills, making replacement and installation straightforward. Supplied as a single piece, it is suitable for targeted repairs, specialty jobs or for keeping a spare bit on hand.

Suitable for

• Drilling and cutting glass and porcelain
• Shaping and grooving ceramics and tiles
• Working on fiberglass and composites
• Light cutting and deburring of non-ferrous metals and hard plastics
• Precision rotary tool tasks and specialty repair work

Key specifications

• Cutting wheel diameter: 38 mm
• Shank diameter: 3/32" (2.35 mm)
• Coating: diamond abrasive on cutting surface
• Intended materials: glass, porcelain, ceramics, fiberglass, non-ferrous metals, hard plastics
• Design features: cooling holes to reduce heating
• Quantity: 1 piece

How to use

Secure the diamond drill bit in a compatible rotary tool or drill with a 3/32" (2.35 mm) collet or chuck. For drilling glass, ceramics and similar brittle materials, use a steady low-to-medium speed and apply light, consistent pressure. Where possible, supply water or other coolant to the area or take advantage of the bit's cooling holes to reduce heat and prevent burn marks. Withdraw periodically to clear debris and check progress. For cutting or grinding operations, keep the tool moving to avoid localized overheating and achieve an even finish.

Usage recommendations

Use personal protective equipment such as safety glasses and a dust mask when working with brittle or dusty materials. Start on a scrap piece to set correct speed and pressure, and maintain a coolant flow or intermittent operation to extend bit life and preserve workpiece quality.