Triangular scraper - when to use?

[student123]

Last October on advice in a book I bought a triangular scraper , but not used it yet.
The book says it essential , a bit of an art in using but not much more on it.

A web search didnt give me much about using one.

Not sure if/when I should use it

I'm on a novice build of an oscillator & now need to mate the cylinder (both ali) with the upright.
Asking around, advice I've had is use a diamond brand grind stone I have & wet & dry paper, maybe lap with toothpaste after.

Will the scraper give me a better finish - should I be using that at some stage for mating the engine surfaces?

Mike


Edit : I found by search under three cornered scraper:
http://en.wikipedia.org/wiki/Hand_scraper

As a footnote, the guy who wrote the model engineering book states its quite a skill & he himself isnt equipped to advise how to do it.
So.. if the answer is : stick with wet & dry / lapping, I'll understand.

 

[Tin Falcon]

I think they are for deburing holes and edges. . That is what I use mine for. we used them for that in a shop I worked in. Other alternatives are a file or a little whirligig deburing tool. Also a countersink comes in handy if the hole is deep enough. remember lot of ways to skin a cat lot of ways to perform may machinist operations. Probably many other uses I am not thinking of.
Tin

 

[bearcar1]

Mike, I am glad to hear that you purchased a scraper, they are terrific tools but they do take a bit of a 'touch' to use properly but nothing a bit of experimentation on a scrap piece of metal wouldn't cure. They are usually used to 'break' sharp edges and to de-burr holes and what not but I have on occasion used them to scrape a surface flat. I think that a known flat surface and a bit of oil on some 600-900 grit wet/dry paper would yield a better surface for you.

BC1
Jim

 

[don-tucker]

They are mainly used for scraping in bearing halves,the shaft is blued and the high spots on the bearing shells scraped using a triangular scraper,and as Tin says ,deburring holes.
Don