Handscraping basics - Video

[stefang]

- Warning, not for people who dislike long, talky videos -

I normaly dont plug my own videos, but by the ammount of comments and mails I got over time regarding scraping, I thought I could link them in here

This is a first two part Video, showing the barebone basics of handscraping to create a flat surface, what tools you need, how to sharpen the scraper, how to read the blueing of a workpiece.


Part 1:
https://youtu.be/QJXqHpSh3SE

Part 2:
https://youtu.be/S9N3Q8Qww2A


An angleplate I finished recently, square within 5/100mm over 130mm:

[quasi]

thanks will check it out.

[wierdscience]

Good job!It's not the length of the video that matters,but how much ground gets covered.You manged to cover plenty,thanks for posting!

One question,the radius grinding gauge,is that a bought item or something you did up yourself?

[stefang]

Thanks!

Mueller Nick once had a bunch of these gages lasercut, but Biax sells a radius gage too - Looks suprisingly similar

[BCRider]

...at the end of the day you look like a Smurf.....

What's wrong with that ! ? ! ? ! ?

Watched the first one and I gotta say.... long? Certainly. But you packed more than a half hour of information into it. You, sir, pack in a high IPM value.... That's Information Per Minute So while I had to sit here for a half hour I did not find that it was a "long" video.

Looking forward to watching the second half this evening.

[J Tiers]

In your first picture, the angleplate shows many "bullseye" spots. Those are spots where thr center is lighter color than the periphery. They have a definite dark ring around them.

Those spots are considerably higher than the rest of the surface. And they are higher than the lighter spots which have no dark ring around them.

It is good to "split" those spots only, to bring them down to match the lighter (and lower) spots. Maybe you finished them later than the picture, I cannot see from the other pictures.

[Ohio Mike]

Excellent videos. Looking forward to the next installment(s).

[wierdscience]

Thanks!

Mueller Nick once had a bunch of these gages lasercut, but Biax sells a radius gage too - Looks suprisingly similar

Whatever happened to him?His Youtube page hasn't been updated in awhile.

[JoeLee]

I could never understand all this scraping back and forth, taking down corners that show high, creating other high spots that were not high prior to, and scraping more of the surface away.
Why not just grind it flat on a surface grinder and then scrape "X" amount of low spots or scrape marks per square inch to obtain the proper contact area your looking for. This way all your high spots would still be flat from grinding.

JL............

[J Tiers]

I suppose that is one way to look at it.

You can get the surface as flat as your reference surface by scraping. And with only basic tools plus a reference flat. The reference flat can also be made using the same basic tools, from scratch, by making three.

All your reference tools (flat, straightedge, squares, etc, etc) can be made from scratch, with only basic tools, with the possible exception of a cylinder square. And the finished tools can be as good as you care to make them.

Your grinder can be made flat and accurate by scraping, starting from nothing if necessary.

You make it seem very haphazard, but it is very organized and methodical if done right, progressing steadily from worse to better until done.

[Mcgyver]

I could never understand all this scraping back and forth, taking down corners that show high, creating other high spots that were not high prior to, and scraping more of the surface away.
Why not just grind it flat on a surface grinder and then scrape "X" amount of low spots or scrape marks per square inch to obtain the proper contact area your looking for. This way all your high spots would still be flat from grinding.

JL............

When you start, you are roughing in zones so to speak so until you get coverage all over, you're not really to concerned about individual spots. You are creating new high spots, but the DOC is limited. This is its great strength, because of the limited depth of cut, the whole surface comes perfectly into the flatness of the master...with variance essentially just being the DOC (which you reduce as you finish)

if you had a grinder and the work fit, I too would use it. One might pick scraping over grinding because...

1) there are lots of jobs that won't fit the surface grinder - like the lathe bed or even a big plate - anything bigger than 6 x12 for the home shope
2) lots of jobs would very difficult to impossible without a slideway grinder
3) lots jobs involve mating geometries, close to impossible to the same tolerance on a surface grinder
4) lots of guys don't have a grinder
5) lots of times you are scraping to something other than parallel - ie square

and finally

6) it can be a lot quicker and more accurate for certain shapes......if the nature of the work is such the mag chuck, even turned down will distort it more than a tenth or so. I'll sometimes scrape one side quickly (few bearing points per inch), then grind the other. Its just a faster path to flat and parallel for certain shapes.

DOC on scraping is about a 1/10,000 when finishing. Because its iterative, the differences between the high and low when finished shouldn't be much more than that and the film of oil is supposed to support things such that there is no metal to metal contact. Is that what you were getting at?

[Highpower]

Thanks!

Mueller Nick once had a bunch of these gages lasercut, but Biax sells a radius gage too - Looks suprisingly similar

And they are NOT cheap! But I bought one anyway....

Turns out it was unnecessary though because my "getto" home made grinding/lapping jigs make a radius that matches the gage perfectly every time.

Great job on the videos Stefan.

[Black Forest]

Whatever happened to him?His Youtube page hasn't been updated in awhile.

He told me quite a long time ago that he would need to join Google something or other in order to post more videos and he wasn't going to do that. He got banned from here for pissing on Evan and not stopping. George gave him a choice, leave it alone with evan or be banned. Nick chose to be banned. I don't blame him.

[wierdscience]

He told me quite a long time ago that he would need to join Google something or other in order to post more videos and he wasn't going to do that. He got banned from here for pissing on Evan and not stopping. George gave him a choice, leave it alone with evan or be banned. Nick chose to be banned. I don't blame him.

Shame,I liked his posts.

[Paul Alciatore]

I just finished watching both videos and they are very good. I don't like videos that take too long to show every chip being cut and then long discussions between the action. Your videos seem to have the right ratio of detail and brevity and I think I have learned a lot from them. I specially like your shop made grinder for the carbide scraper blades.

Thanks for taking the time to make them and sharing.