---
product_id: 5823001
title: "Brush Research GB31224 FLEX-HONE®, 3-1/2\" (89mm) Diameter, 240 Grit, Silicon Carbide, For Mild Steel, Stainless Steel, Cast Iron and Softer Ferrous Materials"
brand: "flex-hone"
price: "₨2034"
currency: SCR
in_stock: true
url: https://www.desertcart.sc/products/5823001-brush-research-gb31224-flex-hone-3-1-2-89mm-diameter
store_origin: SC
region: Seychelles
---

# Self-centering & self-aligning design 240 grit silicon carbide for ultra-smooth finishes 3.5" diameter for precise bore sizing Brush Research GB31224 FLEX-HONE®, 3-1/2" (89mm) Diameter, 240 Grit, Silicon Carbide, For Mild Steel, Stainless Steel, Cast Iron and Softer Ferrous Materials

**Brand:** flex-hone
**Price:** ₨2034
**Availability:** ✅ In Stock

## Summary

> 🔧 Elevate your metalwork with precision and polish that speaks volumes!

## Quick Answers

- **What is this?** Brush Research GB31224 FLEX-HONE®, 3-1/2" (89mm) Diameter, 240 Grit, Silicon Carbide, For Mild Steel, Stainless Steel, Cast Iron and Softer Ferrous Materials by flex-hone
- **How much does it cost?** ₨2034 with free shipping
- **Is it available?** Yes, in stock and ready to ship
- **Where can I buy it?** [www.desertcart.sc](https://www.desertcart.sc/products/5823001-brush-research-gb31224-flex-hone-3-1-2-89mm-diameter)

## Best For

- flex-hone enthusiasts

## Why This Product

- Trusted flex-hone brand quality
- Free international shipping included
- Worldwide delivery with tracking
- 15-day hassle-free returns

## Key Features

- • **Proudly Made in the USA:** Crafted by the original inventors ensuring unmatched quality and reliability.
- • **Versatile Compatibility:** Works seamlessly with hand drills, drill presses, and CNC machines for professional-grade performance.
- • **240 Grit Silicon Carbide Abrasive:** Delivers a superior 24-32 microinch finish on mild steel, stainless steel, cast iron, and softer ferrous metals.
- • **Dual-Action Finishing & Deburring:** Simultaneously smooths and deburrs in one setup, saving time and boosting efficiency.
- • **Engineered Oversize for Perfect Fit:** Self-centering and self-compensating for consistent pressure and flawless results every time.

## Overview

The Brush Research GB31224 FLEX-HONE® is a 3.5-inch diameter, 240 grit silicon carbide honing tool designed for mild steel, stainless steel, cast iron, and softer ferrous materials. Its engineered oversize design ensures self-centering and consistent pressure for optimal finishing, achieving a smooth 24-32 microinch surface finish. Ideal for rebuilding cylinders and deburring, it fits bore diameters from 3.251" to 3.5" and is compatible with various rotating spindles. Proudly made in the USA by the tool's original inventors, it guarantees quality and durability.

## Description

Brush Research GB31224 FLEX-HONE®, 3-1/2" (89mm) Diameter, 240 Grit, Silicon Carbide, For Mild Steel, Stainless Steel, Cast Iron and Softer Ferrous Materials

## Features

- [QUALITY]-Proudly Made in the USA. Quality and consistency you can count on made from the inventors and makers of the tool.
- [DESIGN]-The FLEX-HONE is intentionally manufactured oversized. This engineered oversize creates the optimal amount of pressure inside the cylinder wall allowing the tool to be self-centering, self-aligning and self-compensating for wear and easy use.
- [FINISHING BENEFITS]-Offered in a wide variety of grits to achieve specific finishing tolerances as well as a beautiful crosshatch finish. Ideal for rebuilding hydraulic and pneumatic cylinders, engine and brake cylinders, valve guides, pumps, compressors and more.
- [CROSSHOLE DEBURRING]-Accomplish finishing and deburring simultaneously in a single setup. Can be used in virtually any rotating spindle from a hand drill, drill press or CNC equipment.
- [240 GRIT SILICON CARBIDE ABRASIVE]-Excellent on mild steel, stainless steel, cast iron and other softer ferrous materials. Typically achieves a finish of 24 - 32 Microinch (.6 - .8 Micrometer).
- [WHAT'S INCLUDED]-1 Each of a GB Standard Duty FLEX-HONE: 3.500" (89mm) Bore Diameter, 3.50" Abrasive Part Length, 0.310" Shank Diameter, 13.5" Overall Length. For Use on Bore Diameters Between 3.251"-3.500". PLEASE NOTE: ORDER BY BORE SIZE.

## Product Details

- **Material:** Silicon Carbide
- **Brand:** Flex-Hone
- **Grit Material:** Silicon Carbide
- **Bristle Type:** Abrasive Globule Bonded To Flexible Nylon Filament
- **Product Dimensions:** 8"L x 3.5"W

## Images

![Brush Research GB31224 FLEX-HONE®, 3-1/2" (89mm) Diameter, 240 Grit, Silicon Carbide, For Mild Steel, Stainless Steel, Cast Iron and Softer Ferrous Materials - Image 1](https://m.media-amazon.com/images/I/61f9Ueb7-8L.jpg)

## Available Options

This product comes in different **Size, Style** options.

## Questions & Answers

**Q: Wish one is best for a cylinder wall that is 75mm (2.95 inch) ?**
A: For the cylinder wall bore size of 2.95", the 3" Flex-Hone is the correct choice., Enter this ASIN # B002N3AA2A  in the Amazon search bar for the correct hone.

**Q: Hello, my cylinder bore is 3 1/8" what size tool do i need to purchase thank you.**
A: For a 3.125" bore,  your application will require the 3-1/4" (3.250") diameter Flex-hone. The 3-1/4" will work perfectly in the 3-1/8" bore as the 3-1/4" Flex-hones working range is down to 3.000". Thank you for the inquiry.

**Q: Can i use this to hone out an old cast iron pipe?  it's about 3 3/4" now and i want it at 4" id. thanks**
A: This hone is not coarse enough to remove that much material. It would take forever and the hone would wear out first. You would need a lathe to remove that amount of thickness.

**Q: I see that it says tool is oversized. For a cylinder bore of 3.66, should I be getting the 3.75 or the 3.50 model?**
A: 1I bought a 4.50 and used it on a 3.55 bore with no problem I  didn't hone as much as instruction said for large bore, hatch marks were beautiful  so go bigger and you can use it over a broad area of bores.

## Frequently Bought Together

- Brush Research GB31224 FLEX-HONE®, 3-1/2" (89mm) Diameter, 240 Grit, Silicon Carbide, For Mild Steel, Stainless Steel, Cast Iron and Softer Ferrous Materials
- Brush Research FHQ FLEX-HONE® Oil, Specially Formulated Honing Oil, 1 Quart Bottle (32 fl oz)
- Permatex 81950 Ultra Slick Engine Assembly Lube, 4 oz. , Red

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*Product available on Desertcart Seychelles*
*Store origin: SC*
*Last updated: 2026-02-08*