Scraping flat?

[Dudemanrod]

My first adventure into scraping. Want to scrape my compound on my lathe and dovetails on my mill. This is a piece of durabar and dont know what stage this is?

 

[benmychree]

Use less blue so you don't get smears, and use less and less as you go.

 

[Ulma Doctor]

gettin there,
high in the middle

 

[Cooter Brown]

Use less blue so you don't get smears, and use less and less as you go.

He is right... Roll the blue more to thin it and dont apply downward pressure when printing...... Also dont forget to hinge the part and check the low spots with feeler gauges on the surface plate....

 

[Optic Eyes]

Lot of scratching from badly sharpened blades, improper technique

 

[Dudemanrod]

Yea I'm a little farther down the road now but thanks!

 

[GunsOfNavarone]

So I didn't want to start a new thread, so maybe I'll continue here...
I am finding that I am getting scratching more than peeling. Not that the tool I bought is great, but I put a radius on the end and about 5* of relief. It's probably .750" wide and my approach is just enough of an angle so it doesn't skate. Now, being that I can't sharpen HSS tools well enough to use anything but carbide on my lathe probably points to a large part of the problem, I'm really getting a grit off the surface I'm scraping instead of, I don't know, small curls? @Cooter Brown what do you mean by "hinge the part"? Put it down on the ink in a hinged motion over straight down?
How do you use feeler gauge when the space between ink spots (low spots) is so small? I watch plenty of YT videos before jumping in, but I guess I didn't come across any that were for 1st timers.

 

[Uglydog]

I'll intend to make a quick video of hinging tomorrow and post it.
Don't expect any fancy videography!!

Daryl
MN

 

[benmychree]

You will not easily get curled chips off cast iron, although I have seen it done by a professional with very heavy pressure, it will be more like dust you will see, if you are getting scratching, grind a small corner break on the corners of the insert, what are you using to sharpen the insert? scratching can be the result of a poor finish on the insert's cutting edges.by hinging, the meaning is that if you lay the scraped surface on the surface plate and push either end and if it "hinges" on the center and the other end moves, you know that it is high in the center and needs material scraped off the center area, not the ends, on the other hand, if it does not hinge in the center, but on either end, the opposite is true, the part does not have to be inked up to do this.

 

[Uglydog]

In addition to pressure, be attentive to the angle at which you are holding the scraper.
Also, can you feel a sharp edge on the freshly sharpened cutter?
Short hinging video of what benmychree is describing this morning.

Daryl
MN