FLEX-HONE BC27812 Brake Cylinder Hone, 2-7/8 Inch Bore, 120 Grit, Silicon Carbide

FLEX-HONE BC27812 Brake Cylinder Hone, 2-7/8 Inch Bore, 120 Grit, Silicon Carbide

• The Brush Research BC27812 Flex-Hone is a precision-engineered brake cylinder honing tool designed for 2-7/8" (78 mm) bores. Featuring 120 grit silicon carbide abrasive, it delivers a plateau-style, non-directional cross-hatch finish that enhances lubrication retention, sealing performance, and surface condition in mild steel, stainless steel, and cast iron brake components.
• Features:
  • Self-centering and self-aligning filament assembly for consistent contact and efficient deburring of cross-drilled ports :contentReference.
  • 120 grit silicon carbide abrasive balances peak removal and oil valley retention (~35–50 µin Ra).
  • Produces a high-percentage plateau finish free of torn or folded metal.
  • Versatile for brake cylinders, wheel cylinders, hydraulics, pneumatics, valve guides, and similar components .
  • Durably constructed and made in the USA by Brush Research Manufacturing.
• Specifications:
  • Bore Size: 2-'7/8" (78 mm)
  • Abrasive: Silicon Carbide
  • Grit: 120 (Medium)
  • Hone Length: ~3" (abrasive section); Overall Length: ~8".
  • Stem Diameter: ~0.245".
  • Recommended RPM: up to ~900 RPM in drills or lathes.
  • Typical Surface Finish: ~35–50 µin Ra plateau finish.
  • Tool Weight: ~0.38 lb shipping weight.
  • Application: Brake and wheel cylinders, hydraulic/pneumatic bores, valve guides.
  • Country of Origin: USA.
• The FLEX-HONE BC27812 can also be referred to as 2-7/8" brake cylinder hone, BC27812 hone, silicon carbide flex-hone, plateau honing brush, and brake bore hone.

Brush Research Manufacturing has over 60 years of experience developing innovative surface finishing tools. Their patented Flex-Hone® series is widely used in automotive, industrial, and hydraulic applications for delivering high-quality, plateau-style finishes and reliable performance.

Q: What materials is the BC27812 designed for?
A: It is intended for mild steel, stainless steel, and cast iron brake cylinder applications.

Q: Can this tool be used with a handheld drill?
A: Yes, it performs well in drills or brake lathes up to around 900 RPM, provided proper lubrication is used.

Q: What surface finish does 120 grit produce?
A: It creates a medium plateau finish (~35–50 µin Ra), balancing peak removal with oil retention—ideal for brake sealing surfaces.

Q: How long is the tool usable?
A: With correct lubrication and RPM control, the hone can service multiple cylinders before requiring replacement—inspect regularly for abrasive wear.

Q: What lubricant is recommended?
A: Use oil-based honing lubricants; avoid solvents which can degrade the abrasive bond.