[Newbie] Metal Scraping Terminology Question

[jjtgrinder]

I am considering learning the rudimentary elements of metal scraping. I would like to develop
a basic set of skills.
I downloaded "The Art of Metal Scraping" by Robert R Wade. On page 19 , in the third full paragraph. At the end of the first sentence he states "picking a rough bearing". He then goes on to say the rough bearing should be large spots.

What does he mean by this statement?

 

[Andre]

"bearing surfaces" are surfaces that touch each other. I would assume a "rough bearing" would be a surface less refines than a "fine bearing".

When roughing in a bearing surface, it starts with large spots and progresses to finer spots closer together and more evenly spread.

So a rough bearing would consist of large spots or bearing points.

 

[jjtgrinder]

Thank You,

I assumed he is saying to keep the "cuts" made by the scraper relatively large and over a large general area so as to not
create too much work in a general area that you are trying to affect the geometry in.

 

[sidecar580]

"bearing surfaces" are surfaces that touch each other. I would assume a "rough bearing" would be a surface less refines than a "fine bearing".

When roughing in a bearing surface, it starts with large spots and progresses to finer spots closer together and more evenly spread.

So a rough bearing would consist of large spots or bearing points.

EXACTLY>>>>>>>>>>>

 

[Dresden]

I am considering learning the rudimentary elements of metal scraping. I would like to develop
a basic set of skills.
I downloaded "The Art of Metal Scraping" by Robert R Wade. On page 19 , in the third full paragraph. At the end of the first sentence he states "picking a rough bearing". He then goes on to say the rough bearing should be large spots.

What does he mean by this statement?

I am considering learning the rudimentary elements of metal scraping. I would like to develop
a basic set of skills.
I downloaded "The Art of Metal Scraping" by Robert R Wade. On page 19 , in the third full paragraph. At the end of the first sentence he states "picking a rough bearing". He then goes on to say the rough bearing should be large spots.

What does he mean by this statement?

A rough bearing means large spots, if you have good distribution you " pick" the spots meaning a smaller blade, short stroke more accurately applied to the highest point of the bearing point,, this is usually indicated by a shiny point surrounded by blue of various shades.After marking the part rub it on a clean part of the surface plate, or a cleaned off straight edge, this will shine up the highest part of a point making them more obvious, lightly Scrape that point with a short stroke.
This will create smaller points and better distribution necessary for machine ways and master gages.

 

[Ulma Doctor]

JJT,
Wade's treatise is very good, i may add that he's using the hook scraping method, if you are reading the same work i read.
the hook (pull) scrape is opposite of push scraping.
there could be made arguments for and against both methods.

 

[astjp2]

Here is what I am working on, you can see the size of the spots in the blue...there is a big size difference between bearing on the flats of the dovetails and the mount for the compound rest. Tim