Are brake hone grit sizes graded differently to sandpaper ?

[Brian JohnParticipant @brianjohn93961]

220 grit seems quite rough.

[Brian JohnParticipant @brianjohn93961]

Are brake hone grit sizes quite different to sandpaper grit sizes ? 220 grit would be very rough sandpaper and I can't imagine polishing the inside of a brake cylinder with it.

**LINK**

Edited By Brian John on 16/07/2016 11:14:35

Edited By Brian John on 16/07/2016 11:14:49

[roy entwistleParticipant @royentwistle24699]

Brian You don't use sand paper in engineering (usually) the correct tool is either emery paper or cloth

[Brian JohnParticipant @brianjohn93961]

Okay, I usually use wet and dry…the black stuff. Is that emery paper ?

Edited By Brian John on 16/07/2016 11:29:26

[roy entwistleParticipant @royentwistle24699]

Probably

[DustyParticipant @dusty]

Like many things in engineering names persist long after the original material or process has been abandoned. Such is 'Emery' I am not saying it is completely obsolete as I am sure someone knows where to obtain emery cloth/paper. Most modern abrasive sheets are from oxides of various kinds or carbides. For all intents and purposes 'wet and dry is emery.

[JasonBModerator @jasonb]

Posted by Brian John on 16/07/2016 11:13:49:

Are brake hone grit sizes quite different to sandpaper grit sizes ? 220 grit would be very rough sandpaper and I can't imagine polishing the inside of a brake cylinder with it.

It is not meant to polish the bore, as the name implies i is used to HONE the bore where a very fine cross hatch of fine scratches are desirable.

Finer than that would be lapping and then polishing.

The one you link to is ideal for honing model cylinders wher an iron piston ring will be used

[Brian JohnParticipant @brianjohn93961]

But not suitable for Stirling engines, flame eaters or steam engines ?

[Raymond AndersonParticipant @raymondanderson34407]

Brian, You say you use wet & dry That is usually Silicon Carbide. Emery is Aluminium Oxide. With Silicon Carbide the higher the number the finer is the abrasive . Emery has a different grading system [often using letters ] I have a excellent chart from Norton .There will be others available on the net. I will try later to put the chart into me dropbox. and you will get all the info you need there.

[Neil WyattModerator @neilwyatt]

Emery is a natural mineral that is mostly aluminium oxide. Most modern 'emery substitutes' use purer material so effectively the same thing but not actually emery.

Neil

[JasonBModerator @jasonb]

Posted by Brian John on 16/07/2016 13:19:57:

But not suitable for Stirling engines, flame eaters or steam engines ?

OK for steam engines with iron piston rings.

[roy entwistleParticipant @royentwistle24699]

In my books emery is a form of corundum akin to sapphire and ruby

[Michael GilliganParticipant @michaelgilligan61133]

Posted by roy entwistle on 16/07/2016 18:11:08:

In my books emery is a form of corundum akin to sapphire and ruby

.

Then your books are good, Roy

… As Neil said: "that is mostly aluminium oxide"

MichaelG.

[Author]

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