Lapping

[Parksy]

Gday all

I would like to expand my knowledge on internal and external lapping. I watched a video on YouTube of a bloke lapping a rod with a specific tool and achieved a chrome like finish on the rod. But the tool he used was only for that specific sized rod. He could adjust it slightly to cater for wear, but reading a lot of posts here and everyone is lapping this and that of all various sizes. Do you make the lapping tool? How do you make a tool to lap say a cylinder bore?

Thank you all for reading

Andy

 

[Blogwitch]

There is a slight difference between lapping and honing.

Honing is usually done on i/c engine bores, where minute scratches are imparted onto the running surface. This allows oil to stay in the bore wihile the engine (usually with a metal piston ring) is run in. After a while, the combination of scraping by the piston ring and surface friction between the piston and bore actually wears the internal surface (and so the scratches) to a perfect matching fit.

A set of hones can be bought fairly cheaply to do this job. They will also slightly straighten a bore if it is say tapered, if used correctly.

http://www.amazon.co.uk/dp/B000RO7THQ/?tag=skimlinks_replacement-20

Lapping a bore is slightly different.
This is where a bore is brought to an exact size with a very finely finished bore. You would normally use this system on say a steam or air driven engine, where eventually both the piston and bore are lapped together to form a perfect running fit, and it normally doesn't need to be run in.
In the US, copper laps are readily available at very cheap prices, but where I live, that is not the case and we have to make our own and use different methods. I don't know what it is like in Oz.
I normally use Delrin to make my laps and embed a cutting agent in the surface by rolling the two together on a hard surface.

Members from the US will be able to show you using copper laps more than I can as I have never had any experience with them.

Then you can go into the realms of industry using the Delapena system, someone on here might be able to show you that if they are lucky enough to have one in their shop. But you should be able to search those out on the net and get the info you require.

I know this doesn't show exactly what you require, but with a little searching, with what I have told you, you should be able to get a good insight.

John