[Metrology] First scraping project: scrap iron straight edge

[AndySomogyi]

Thanks Richard, Lance does a great job of explaining a lot of stuff, especially the tool grinding. I like Adam, I've watched a lot of his vids, he's got a lot of fun projects, learn a lot of techniques from him.

I did find Dale's video here, and it's fantastic, he managed to answer a bunch of questions that I came up with in my first clueless attempt. Dale's is great because he goes over the full process of starting with a rough blank, getting it flat (he doesn't mention hinging interestingly which I think very important, learned that from Stephan G), but Dale great with how to deal with a bow, and how to approach roughing to shape.

So, metal for Claugh42's scraper is here, genuine Sandvik bit should be here next few days, will make a real scraper, and learn to sharpen it the right way, and will give it another shot.

Basically I started this thread as a sort of 'lab notebook', where I record what I do, record the inevitable mis-steps, when I get further along, hopefully some success.

 

[AndySomogyi]

Stephan G's series on scraping is also extremely good, he's a fantastic presenter, and his videos are very well organized and thought through. You can clearly tell how much effort he puts into being clear, and presenting information in an entertaining and maximally informative way. Well done Stephan.

 

[AndySomogyi]

Got the real scraper blade in the mail today.

Thanks James, your channel rocks.

Sent from my iPhone using Tapatalk Pro

 

[Polktools]

@AndySomogyi How did things end up with that straight edge?

 

[AndySomogyi]

@AndySomogyi How did things end up with that straight edge?

It's on the back burner until I get my lathe working.

 

[AndySomogyi]

This is literally my second ever attempt at scraping, so what can I do to improve. The issue that I seem to be struggling with is oddly enough inking it up so I can see the ink, and not using too much ink so it covers everything. The ink works easily with the parts are rough, be when it gets close to finish, having a hard time seeing the blue.

I’m using the yellow Charbonnel that others have recommended for a contrast, and I’m using Permatex Prussian Blue as the ink.

I think right now it’s about 30 PPI or so, and I’d like to improve it. I think I put the blue ink on too heavy in the top pic.

I needed a straight edge to scrap in the top slide on my lathe project. So I made a mini-scraper to get into the dovetails.

I used the mini scraper to scrape this prism straight edge I made from cast iron. The carbide blade is 0.5 wide, and sharpened with diamond lap to 0° rake angle (per Connelly).

 

[benmychree]

The pictures above show the yellow color being used on a sample part being scraped, actually the yellow is used as a background color, applied very thinly on the part to be scraped to contrast with the prussian blue marking color to make the high spots stand out more visably. I do like the water based colors much better than the old oil based colors previously used, cleanup is much easier, using Windex. For many years I used red lead for marking, still do so sometimes, it was one of the old standards and works well, but messy, not to mention toxic.
I would add that Permatex prussian blue is an oil based product and is quite messy, the Carbonnel product (prussian blue) is water based and easy to clean up, as is the yellow.

 

[JRaut]

@AndySomogyi is documenting his journey, warts and all. He's not claiming to be an expert, or suggesting he's doing it correctly; he's candidly documenting his thought process and trials and tribulations. That's a good thing. We can all afford to learn from that.

 

[middle.road]

I believe it was Tom Lipton's video using Charbonnel that led me to buy it. He seemed to have a decent method for using it.
I purchased Prussian Blue and Yellow.
When I first went to check out my cross slide I used Dykem and my results were mixed. i.e.: I don't have the 'touch'.
When I did it up with Charbonnel it came out better and know I know what I need to focus on in an _attempt_ to repair it.
Just need to find the time... and get the shop organized & cleaned up.

 

[Dabbler]

In order to stop things from getting out of hand here I have edited two posts. Complaints - please PM me. @AndySomogyi - great thread, keep up the good work!