Scraping compound slide resources

I recently learned about scraping and was immediately interested however resources seem sparse. I’ve read about making a scraper from a file and how to scrape flat but I can’t find information on how to scrape dovetails? Could you guys let me know what tools are necessary and guidelines for the technique. I would really appreciate any help
Thanks!

YouTube is your friend.

Abom79, Keith Rucker, Stephan Gotteswinter, Robrenz, many others.

I’ve yet to see a video in which it is shown how to apply blue to the underside of the dovetail. Can you recommend a specific video?

You should probably think through the whole step by step process for a compound slide and some of the answers will pop up.

Sooo. The upper of the compound will generally have a flat surface. So it can be checked against a surface plate and scraped to be sure it's a flat plane with good bearing. The bottom of the compound will also have a flat that bears on the top of the crosslide. IF it has a boss that fits into the crosslide it still needs to be planar, just that you need a small surface plate with a recess in the middle. Think of this as a secondary plate that can be verified from the primary surface plate and can then be used to verify the bottom of the compound.

So, fix the bottom of the upper, make sure that the bottom of the lower is good and then you can work the flats of the lower section using the now-flat upper as a reference. When you know the flats on the top of the lower section are flat, then also make sure they're parallel to the underside, using 1-2-3 blocks or parallels and your surface plate. Adjust as necessary for both flatness and parallelism.

This is all just preparatory to working on the dovetails. So now you can use your small straightedge to check and fix the first dovetail surface, the one on the lower section that's closest to the headstock. You'll put bluing on the straightedge and see how it transfers to the dovetail. You don't need to fret about precise angle, just be sure it's a good flat surface. When that's a good surface you can work next on the opposite side. It needs to be flat and also parallel with the first side. Adjust as needed.

When all that is accomplished, you can turn next to the female dovetails in the upper half of the compound. Now we get to "how you blue up the dovetail". Some people make up a small stick with an angle on the end that might be fabric or leather covered to use as a spreader. At the other end of the process scale you can use your fingers to smear on bluing and rub back and forth to get an even coating. There are foam paint rollers designed for inside corners that might work. In any case, you can now use the blued up (and now accurate) compound lower section to work on the dovetails of the upper. And then there's the gib to deal with.

That's a long-winded way of talking about how to blue up a dovetail, but the final product is built from all the procedures before it.

IMO, for every bit of effort you put into scraping, you need to put twice was much into inspecting your machine/parts and knowing where and how much material you need to remove.

I believe Keith Rucker did a series on tuning up the carriage, slide, and compound on his Monarch.

And search this site for anything written by Richard King.

I've had success with a piece of scrap cast or ductile iron milled and scraped flat with a 45 degree on one side for bluing up dovetails. A proper camelback straightedge is of course preferred, and a member recently posted links to extremely affordable straightedges from Martin Model & Pattern - your online source for fine quality patterns and castings.

+1 to TGTools' description but I'll observe that while maintaining/restoring the original geometry is critical...a lot of benefit can be accomplished by simply scraping out the hourglass wear that occurs on many compounds. It's not right or sufficient but it's expedient.

I taught Keith Rucker to scrape. I am in several of his you tube show. On You Tube search "Richard King Scraping and you will see several of my students: Abom79, NYC CNC, Keith Rucker, Stefan G and a for more. show how to used inks and scrape. I sell a DVD on scraping and the application of the inks. Also f your n The bay area of CA/ I will be teaching a scraping class there in April