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Flex-Hone Specifications & Sizes

Standard Flex-Hone Sizes & Grits

The standard Flex-Hone range is made from Silicon Carbide abrasive and comes in diameters ranging from very small 4mm to very large 475mm (18"). Aluminium Oxide abrasive is also generally available in Flex-Hones in a range of diameters to suit small tube up to 100mm for engine cylinders. The main abrasive grit sizes are 180 grit (medium) and 240 grit (medium fine). Specified grit sizes in Flex-Hones are not at all similar to grit sizes in other grinding media such as grinding wheels or abrasive cloth or paper.  For instance a surface finished with a 180 grit Flex-Hone would produce very much finer surface patterns than a 180 grit sheet of cloth abrasive. Flex-Hone finish can also be varied by using different weights of lubricant during honing. For instance grease smeared in a cylinder bore before Flex-Honing will produce a finer cut than oil. Other grit sizes generally available in Flex-Hones are 120 grit (coarse), 320 grit (fine) and 400 grit (extra fine).

Factory Special Flex-Hones

Flex-Hones can be made to order for special applications. Possibilities include grit sizes from 20 grit to 800 grit and very large diameters up to 900mm (36"). Factory specials are also available in non standard abrasives such as Boron Carbide, Tungsten Carbide, Alumina Zirconia, Levigated Alumina, Diamond and CBN.

Selecting Correct Grit Size for a Flex-Hone

The grit size required for a particular job will be determined by a number of factors. These factors include such things as the type of material being honed, the type of engine rings or hydraulic seals used and the grade of lubricant used in service in the engine or machine. As explained above choice of cutting lubricant used during the honing process also affects finish and grit selection. If finish is critical, the only conclusive way to establish the best grit size for an application is by conducting tests on the actual job. Probably 99% of general applications produce a very satisfactory finish using either 180 grit or 240 grit coupled with variations of cutting lubricant. Coarser and finer grits can increase the cost of the tool substantially so they are generally reserved for special and critical applications.

How to Select the Correct Size Flex-Hone

The Flex-Hone tool is flexible and each size of tool can be used over a range of bore sizes. The nominal diameters shown in the table below give the maximum diameter that each tool will hone. A Flex-Hone will compress by up to 10% to suit a minimum bore size of 90% of its nominal diameter. It should be noted that a new Flex-Hone is approximately 10% larger than the nominal diameters shown to ensure spring tension on the bore and to compensate for wear.


BC Series

200mm overall length


Flex-Hone Size Tables

GB Series - Normal Duty

340mm overall length

GBD Series - Heavy Duty

Overall length to suit size

GBD Large Cored Series

Separate long hex shaft

Rejuvenate Large Engines

Rejuvenate large engines with Flex-Hones anti wear surfaces produced on cylinders without removing engine  from vehicle or ship

Recondition Large Machinery

Recondition large mining and earthmoving equipment with Flex-Hones for longer life
Anti wear finish produce by Flex-Hone increases life of parts customers report hydraulic seals lasting even up to 9 times as long

Finish Hydraulic Cylinders

Hone hydraulic cylinders with Flex-Hones for ultimate results. Customers report even up to 9 times the life of hydraulic seals


Flex-Hone cylinder hone tools increase the service life of many pieces of equipment by very worthwhile amounts. For instance  customers report  such things as double life between heat exchanger cleaning - up to 9 times the life of hydraulic seals and in race car engines  - far less downtime etc., etc.


How does Flex-Hone offer these gains?

Well, let's explain . . . when you finish by using Flex-Hones you produce a more frictionless surface than you could create with any other tool and by doing this you prevent premature wear in any mating parts like piston rings and seals. And in heat exchanger tubes you produce a finish that's actually better than new . That's why you get such radical improvement in the service life and performance of equipment.


Comparison - Rigid Hones or Cutting Tools

The reason you gain these advantages is because Flex-Hones use a totally different method of metal finishing to  any other machining or surface treatment process. We call it "downwards" finishing. Almost all other types of  metal processing use "upwards" cutting. Let's explain . . . rigid hones or cutting  tools of any type must penetrate below the surface and lift material up and off the workpiece. Ordinary abrasives and rigid hones  do exactly the same thing because they're just like thousands of miniature cutting tools. This always leaves a jagged finish even if it's so minute you can't see the sharp peaks (see Diagram #1 and the corresponding roughness readout at right).On the other hand Flex-Hones rub from the top of the work surface and smooth the jagged peaks downwards leaving a "plateaued" or flatter finish without jagged peaks (See Diagram #2 and the corresponding  roughness readout).

Descale Heat Exchangers & Boilers

Descale & clean heat exchangers & boilers with Flex-Hones for far longer periods between routine maintenance cleaning










Diagram #1 Microscopic schematic & roughness readout

WITHOUT Flex-Honing

Rouighness tester readout graph shows sharp peaks without or before Flex-Honing









Diagram #2

Microscopic schematic & roughness readout

AFTER Flex-Honing

Roughness tester graph after Flex-Honing shows smoothed surface for wear prevention yet small troughs retaing for lubricant supply

Flex-Hone Tool - Ball Hone,  Cylinder Hone Tools

Also Deburring, Boiler Cleaning - Heat Exchanger Cleaning Tools



Large Flex-hone (ball hone) sizes up to 480mm or 19" for marine & large diesel or hydraulic cylinders
Flex-Hone (ball hone) bottlebrush hone tools give ultimate life extension of hydraulic & engine cylinders or cleaning descaling heat exchangers

<  ------------------ From 480mm Large to  4mm Miniature ------------------  >

       In Stock

        and up to 900mm special orders

Long spindle Flex-Hones for firearms treat guns to bring them back to almost better than new performance







Gun Cleaning Flex-Hones

Miniature Flex-Hone tools from 4mm diameter let you finish and deburr very small parts

Honing with Flexhone (ball hone) - Australian importer of cylinder hone tools for honing cylinders - deburring - boiler cleaning & heat exchanger cleaning . Used in hydraulics & engines - diesel, petrol & large marine engines down to small 4mm valve guide & tube sizes. Flex-Hones give you increased service life in many types of equipment - hydraulic and engine cylinders show dramatically decreased wear on mating parts and seals after Flex-Hone finishing.  Boiler heat exchanger tubes stay clean & descaled much longer if cleaned with Flex-Hone.  This is because Flex-Hone removes "plateaus" i.e. flattens and smooths the tops of the minute sharp hills which are invariably left by any other machining or ordinary fixed stone honing.  Flex-Hone is a great remedy for oil burning and hydraulic fluid leakage. So whether you need to remove scale in boiler heat exchanger tubes or repair everyday engine and hydraulic cylinders, a Flex-Hone treatment is the superior way to finish your work.

How to Deburr Quicker & Better

Why Flex-Hone?



or your MONEY BACK

on  stock  lines

What RPM Should You Use for Flex-Hones?

Flex-Hones are low RPM tools. The RPM you will use depends mainly on the diameter of the Flex-Hone and also on what your application is. The table [left] is only a guide. You will need to work out what suites your requirements by experiment.


Stroke Rate

The number of times you plunge in and out per second or "stroke rate" is only important if you need to create a cross hatch pattern.  As a guide with Flex-Hones 125mm diameter or less start at 1 stroke per second then speed up or slow down the rate to get your selected cross hatch angle.  The video [link below] demonstrates general use including stroke rates etc.

What Surface Finish Can You Expect from Flex-Hones?

Table of likely surface finishes produced by Flex-Hones of different grits

You will need to assess grit selection by considering the time budgeted to do your job and the degree of surface finish improvement you want.  If your starting surface has a coarse finish you may need to use a range of Flex-Hones with progressively finer grits before you get to the finish you require.  The chart [at right] is only intended to offer a starting point in selecting grits.  Because type of material and original finish can differ widely from job to job,  the only real way to determine what works for you on a particular job is by actual trial and measurement.


Flex Hone (ball hone) Cylinder Hone Tools Range Kits

Hydraulic Kits


3a Small  -  6.4mm; 7mm; 8mm; 9mm; 10mm; 11mm; 12mm; 1/2”; 5/8”; 3/4”; 7/8”; 1”;

3a Small (Extended) -  6.4mm; 7mm; 8mm; 9mm; 10mm; 11mm; 12mm; 1/2”; 5/8”; 3/4”; 7/8”; 1”;  1-1/4";  1-1/2"  &  1-3/4"

3b General Range  -  2”; 2-1/8”; 2-1/4”; 2-1/2”; 2-3/4” & 3”

3c Medium  -  3-1/4”; 3-1/2”; 3-3/4”; 4-1/8”

3d Large  -  4-1/2”;  5”;  5-1/2”;  6”;  6-1/2” & 7”


Engine Kits


4a Small & 2 Stroke  -  2-1/8”; 2-1/4”; 2-1/2”; 2-3/4”; 3”; 3-1/4” & 3-1/2”

4b Domestic Mower -  2-1/8”; 2-1/4”; 2-1/2”; 2-3/4” & 3”

4c Cars & Light Truck  -  3-1/4”; 3-3/4”; 4-1/8” & 4-5/8”

4d Large & Diesel  -  4-1/2”; 5"; 5-1/2”; 6”; 6-1/2”; 7”

4m Motorcycle  -  2-1/8”; 2-1/4”; 2-3/8”; 2-1/2”; 2-5/8”; 2-3/4”; 2-7/8”; 3-1/4” &  3-1/2”


Valve Guide & Small Hole Kits

2V - 6.4mm; 7mm; 8mm; 9mm; 10mm; 11mm; 12mm; 1/2”


Brake Cylinder & Small Engine Kits


2a Small - 18mm; 20mm; 7/8”; 1” & 1-1/8”

2b Extended - 1-1/2”; 1-5/8”; 1-3/4”; 1-7/8” ; 2”; 2-1/8”;  2-1/4”; 2-1/2”; 2-3/4” & 3”

What Variations of Flex-Hone Cylinder Hone Tools Kits are Available?

Flex-Hone (ball hone) cylinder hone tools come in the above kits generally in 2 Silicon Carbide grit sizes 180 grit and 240 grit. These are the most popular grits in the whole Flex-Hone range. In many sizes, you can also get Aluminium Oxide 240 grit abrasive.  You could also custom design a range for yourself and 320grit and 400 grit Silicon Carbide can be made up as special ranges of Flex-Hone (ball hone) cylinder hone tools if required.

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