Solid Drill Bits

Solid Diamond Drill Bits – Flat End Cylindrical Diamond Burs for Stone, Glass & Gemstone Drilling & Carving

Professional flat end cylindrical solid diamond drill bits for drilling, carving, and channel cutting in stone, glass, ceramic, and gemstone materials. Available in three shank sizes — 2.35mm (100pcs bulk packs for Dremel and hobby rotary tools), 3mm (10pcs for Foredom flex shaft), and 6mm (10pcs for die grinders and professional rotary tools) — across 0.4mm to 40mm head diameters in 45, 60, 80, 120, and 240 grit. The flat end cylindrical profile produces clean flat-bottom holes, channels, and carved recesses ideal for inlay work, bead drilling, pendant holes, and precision stone carving.

🔥 Shop Solid Diamond Drill Bits – From $8.00

2.35mm Shank – 100pcs Bulk Packs (Dremel / Hobby Rotary Tools)

Head Diameter Grit Pack Price
0.4mm – 1.0mm 80 100pcs $12.00
1.2mm – 1.5mm 80 100pcs $12.00
2.0mm – 2.5mm 80 100pcs $12.00
3.0mm 80 100pcs $12.50
4.0mm 80 100pcs $18.00
5.0mm 80 100pcs $28.00
6.0mm 80 100pcs $42.00
8.0mm 80 100pcs $28.00

3mm Shank – 10pcs Packs (Foredom Flex Shaft / Professional Rotary Tools)

Head Diameter Grit Pack Price
1.5mm – 8.0mm 80 10pcs $14.00
4mm – 5mm 45 10pcs $8.00 – $9.00
6mm 45 10pcs $10.00
8mm 45 10pcs $11.00
10mm 45 10pcs $11.00

6mm Shank – 10pcs Packs (Die Grinders / Professional Rotary Tools)

Head Diameter Grit Pack Price
5mm – 12mm 60 10pcs $12.00 – $14.00
14mm – 16mm 60 10pcs $19.00 – $28.00
18mm – 20mm 60 10pcs $32.00 – $40.00
25mm – 30mm 60 10pcs $48.00 – $56.00
10mm – 18mm 80 10pcs $8.00 – $9.50
20mm – 30mm 80 10pcs $10.50 – $11.00
35mm – 40mm 80 10pcs $12.00 – $12.50
6mm – 10mm 45 10pcs $15.00 – $17.00
10mm – 12mm 45 10pcs $17.00 – $18.00
6mm – 10mm 120 10pcs $14.00
12mm – 16mm 120 10pcs $20.00 – $30.00
18mm – 20mm 120 10pcs $45.00 – $50.00
25mm 120 10pcs $58.00
10mm – 18mm 240 10pcs $8.00 – $9.50
20mm – 30mm 240 10pcs $10.50 – $11.00
35mm – 40mm 240 10pcs $12.00 – $12.50

Grit Selection Guide

Grit Application
45 (coarse) Fast material removal, rough hole opening, aggressive carving
60 (medium-coarse) General drilling and carving on hard stone and glass
80 (medium) Balanced speed and finish — most common general-purpose grit
120 (fine) Cleaner hole walls, detail carving, finishing passes
240 (very fine) Fine detail carving, smooth channel walls, delicate materials

Shank Size Guide

Shank Compatible Tools Best For
2.35mm Dremel, hobby rotary tools Fine detail work, small diameter drilling (0.4–8mm), economical 100pcs bulk packs
3mm Foredom flex shaft, professional rotary tools Jewelry carving, bead drilling, small to medium diameter work (1.5–10mm)
6mm Die grinders, professional rotary tools Larger diameter drilling and carving (5–40mm), production stone carving

Compatible Applications

  • Flat-bottom hole drilling in stone — agate, jasper, quartz, turquoise, jade, obsidian
  • Inlay channel cutting and recess preparation for stone and metal inlay work
  • Gemstone bead drilling and pendant hole drilling
  • Glass surface carving and channel cutting
  • Ceramic and porcelain drilling and carving
  • Stone setting seat preparation and bezel recess carving
  • Production carving with 100pcs bulk packs (2.35mm shank)

Related Tools

Frequently Asked Questions

  • Q: What is the difference between solid drill bits and core drill bits?
    A: Solid flat end cylindrical bits grind through the full diameter of material, removing all material within the hole as slurry — producing flat-bottom holes, channels, and carved recesses. Core drill bits remove a cylindrical plug through the center, leaving a core — faster for larger through-holes and generating less heat. For flat-bottom holes, inlay channels, carving applications, or holes under 6mm, solid bits are the standard choice.
  • Q: Which shank size do I need for my rotary tool?
    A: 2.35mm shank fits Dremel and most hobby rotary tools — available in 100pcs bulk packs for economical production use. 3mm shank fits Foredom flex shaft machines and most professional rotary tools — the standard for jewelry carving and lapidary work. 6mm shank fits die grinders and larger professional rotary tools for larger diameter drilling and carving (5–40mm head diameters).
  • Q: Should I use water cooling with solid diamond drill bits?
    A: Yes — always use water cooling when drilling or carving with diamond bits. Water prevents heat buildup that can damage both the bit and the workpiece, extends bit life significantly, and produces cleaner hole walls and carving surfaces. Use a water drip system, work in a shallow water bath, or use a clay dam reservoir around the drilling area.
  • Q: What grit should I choose for drilling gemstones?
    A: For most gemstone drilling, 80 grit provides the best balance of drilling speed and hole quality. Use 45 or 60 grit for faster material removal on harder stones (Mohs 7+). Use 120 or 240 grit for cleaner hole walls on delicate materials, fine detail carving, or when a smooth finish inside the hole or channel is required.
  • Q: Why are some packs 10pcs and others 100pcs?
    A: 2.35mm shank bits are sold in 100pcs bulk packs because they are used in Dremel-type tools for high-volume production carving and drilling — the smaller shank size and lower per-bit cost make bulk packs practical. 3mm and 6mm shank bits are sold in 10pcs packs as they are used in professional rotary tools for more controlled, lower-volume work where individual bit life is longer.