Hand Scraping a Surface Plate to Sub 5 Micron / A - Grade Flatness

Hello and welcome,

in this video I'm showing you how I handscraped my steel surface plate to a flatness of less than 5 microns (0,2 thou).
It ended up beeing somewhere inbetween 3 and 4 microns of flatness.
That's 0,003-0,004mm. So not that much.

All scraping was done by hand.
Roughing with a 30mm/25mm carbide blade with 140mm radius.
Finer scraping was done with a 25mm carbide blade and 90mm radius, final scraping was done with 60mm radius.

For scraping basics check out ‪@StefanGotteswinter‬ 's channel, he has awesome basic videos about scraping. My ghetto carbide grinder is also inspired by him.
   • Scraping basics - Scraping flat - Part 1  

MUSIC:
The Gentlemen - DivKid
Snowy Peaks pt I - Chris Haugen
Snowy Peaks pt II - Chris Haugen
Pink Horizon - Chris Haugen
Soft Feeling - Cheel
Sunday Rain - Cheel
Sunset Dream - Cheel
Blue Dream - Cheel
Lazy Walk - Cheel
Smokey Eye - Cheel
Campfire Song - Chris Haugen
Blue Creek Trail - Dan Lebowitz

00:00-02:55 Intro
02:56-20:50 Rough scraping
20:51-22:37 Carbide grinding
22:38-30:12 Fine scraping
30:13-34:45 Measurement method
34:46-40:55 Metrology theory
40:56-44:45 Measurements and results
44:46-47:02 Bonus