View Full Version : The perfect 90

05-19-2008, 06:23 PM
This is all just theory and related to making a surface plate (er 3) flat. Could a similar process be used to create a reference set of 90 degree angles?

1. Weld up 3 roughly 90 angles (L-shaped welding of flat bar with 45 degree braces)
2. Grind/sand/file/mill off the corners
3. Blue and scrape in A->B->C->A fashion bluing from one vertical surface to another while the horizontal surfaces rest on a surface plate.

Would that process work, and would it be the most efficient way to go about creating 90 degree references?

05-19-2008, 06:39 PM
I wouldnt weld it. Anything you can weld is not something you would want to make it out of.

You want cast iron for this.

I would just start with a cheap ground cast iron angle plate from somplace like Shars. The ones I have bought have been very accurate.

J. R. Williams
05-19-2008, 08:10 PM
Start with a large engine piston pin and make it into a 'cylinder square' for use with your surface plate.