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High-quality honing and finishing tools
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Over 60 years of experience
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3100 tools in stock
Honing tools for cylinders · Ø 4-457 mm · in stock

Flex-Hone® cylinder hone in your bore size

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After reboring or before fitting new rings: chucked in a drill or spindle, the Flex-Hone tool produces the defined cross-hatch pattern that ring bed-in requires – no honing machine, no fixture, in 10-45 seconds per cylinder.

  • Cross-hatch with an included angle of ~45° – the established convention for oil retention and ring bed-in
  • Self-centring in the drill chuck or cordless drill – no set-up, no honing machine
  • Engine sizes 60-105 mm in stock – availability and dispatch date shown on each item

Enter the nominal bore size of your cylinder in mm – we will show the matching size.

mm
Unsure about material, coating or tolerance? Request a tool recommendation
Already know your size? Straight to the size selection →
60+ years of experience
ISO 9001 certified production
3,000+ tools in stock
30 days payment terms on invoice

Flex-Hone® for engine cylinders – most-ordered sizes in stock

Grit 180 SC is the standard for ring bed-in and plateau finishing on grey cast iron and steel; 240 for a finer target roughness. Uncoated aluminium: select aluminium oxide (AO) via the finder.

Ring bed-in finish without investing in a honing machine: engine sizes from 36.70 € net.

Sizing: order the nominal bore size of your cylinder – the oversize is built into the tool. In-between size (e.g. 86 mm)? Choose the next larger standard size (89 mm).

All prices net plus VAT. · Shipping within Germany from 5.90 €.

Flex-Hone oil (1 l)
Goes well with it: Flex-Hone oil (1 l) – 8.95 € net
View all sizes and grits in the shop →
Selection criteria

Which grit for which task?

Task Grit Price example (net)
Levelling a glazed or scored bore surface 120-180 SC from 35.40 € (60 mm/180 SC)
Ring bed-in and plateau finish (standard) 180-240 SC 47.00 € (76 mm/180 SC) · 57.60 € (89 mm/180 SC)
Finer target roughness, sealing surfaces 240-320 Select your size in the finder →
Nikasil / hard chrome (coated) Diamond Go to the Nikasil page →

All prices net plus VAT and shipping. Uncoated aluminium: choose aluminium oxide (AO) instead of SC.

Tool finder

Enter your cylinder Ø – find the right Flex-Hone in 30 seconds

If diameter and material are settled, the finder leads straight to the matching Flex-Hone®. For coated bores, series production or drawing parts, the technical enquiry is the safe route.

  1. Enter the bore diameter
  2. Select the material
  3. Specify the target finish – get a directly orderable recommendation
Macro shot of a honed cylinder wall with a uniform cross-hatch pattern

Cross-hatch the way rings need it.

Plateau finish with oil retention volume – the goal of every ring bed-in.

When Flex-Hone® is the right choice – and when the honing machine is

The Flex-Hone tool is a finishing tool: it produces cross-hatch, plateau finish and deglazed running surfaces, but it corrects neither size nor geometry. After reboring, before fitting new piston rings, or to break the glaze of a run-in bore, it is the fastest route to a defined finish.

Oval, tapered or worn cylinders need rigid machining first – Flex-Hone then takes over the final step. Precisely this division of labour makes the tool attractive for reconditioning work: no machine investment, no re-clamping, reproducible results.

Flex-Hone tool in a cordless drill honing a bore directly on the engine block
Right at the block: Flex-Hone in the drill chuck – no need to move the block to a honing machine.

The right size: order the nominal bore size

The tool is manufactured larger than its nominal size – this oversize creates the contact pressure of the abrasive globules. So you simply order the nominal size: 76 mm cylinder → 76 mm Flex-Hone. If your bore lies between two standard sizes (e.g. 86 mm), take the next larger one (89 mm). Rules of thumb such as “add 10-20% oversize” lead to wrong purchases.

Diagram: the order size is the nominal bore size – in-between sizes are rounded up to the next standard size
  1. Tool manufactured slightly oversize (dashed) – the contact preload is built in. So: order the nominal size, bore Ø 50 mm → 50 mm tool.
  2. Measured an in-between size (e.g. 86 mm)?
  3. Order the next larger standard size (89 mm) – never round down: an undersized tool builds no contact pressure.

How the cross-hatch is created: rotational speed and stroke speed

The cross-hatch angle results from the ratio of rotational speed to stroke speed – the target is the established convention of roughly 45° included angle. Guide values by cylinder Ø: 64-76 mm at 600-900 rpm, from 100 mm at 350-600 – never above 1,200 rpm.

Always work with oil or emulsion and stroke the rotating tool evenly: in practice, 10-45 seconds or 5-12 complete strokes per cylinder are enough. Honing for longer improves nothing – it only shortens tool life.

Flex-Hone honing tools in various diameters
One design from 4 to 457 mm: engine sizes 60-105 mm are in stock.

Coated cylinders? Nikasil and hard chrome require diamond

Everything above applies to grey cast iron, steel and uncoated aluminium. Nikasil, hard chrome and other coatings above 50 HRC cannot be cut by silicon carbide or aluminium oxide – here the diamond version is the only correct choice. Our dedicated page on honing Nikasil shows how to do this safely.

Honing Nikasil cylinders: the diamond solution →
Related topics

Matching applications and guides

FAQ

Technical

Questions about tool, material and process

Can I hone cylinders with a power drill or cordless drill?
Yes – that is what the tool is built for. It centres itself in the bore. Guide values: 64-76 mm at 600-900 rpm, 89-95 mm in the lower part of that range, from 100 mm at 350-600 – never above 1,200 rpm. Enter and exit the bore with the tool rotating, and stroke evenly.
How long should I hone – and how do I recognise the result?
In practice, 10-45 seconds or 5-12 complete strokes per cylinder. The result is a uniform cross-hatch pattern with an included angle of roughly 45° across the entire running surface. Honing for longer does not improve the pattern.
Does the tool remove stock from the bore?
Not to a dimensionally relevant degree: material removal concentrates on roughness peaks and the glaze. Size and form correction (oval, tapered) is the job of rigid machining beforehand – the Flex-Hone tool then delivers the finish.
What lubricant should I use?
Always work with oil – a low-viscosity honing oil keeps the removed material in suspension; engine oil also works. Running dry drastically shortens tool life. Not suitable: WD-40 and solvents such as brake cleaner. You will find a suitable honing oil in the product block under “Goes well with”.
Buying & advice

Terms, delivery and B2B handling

What does honing a cylinder with Flex-Hone cost?
The tool for common engine sizes costs 35.40-69.95 € net (60-105 mm, grit 180-240) and, with correct lubrication, lasts through many cylinders. For comparison: a single outsourced job often costs more.
Do you deliver from stock?
Yes – over 3,000 tools are held in stock in Germany; the exact dispatch date is shown in the stock-status line on each item. Invoice with 30-day payment terms for business customers.
My bore is between two sizes – which one should I order?
Always the next larger standard size: measured 86 mm → order 89 mm. Never round down – an undersized tool builds no contact pressure. The selection assistant does this automatically.
Question not covered? Send us your part, bore size and a photo – you will usually get an answer within 24 h.
Request a tool recommendation Find your tool by size