Engineers reference flat

[Richie]

You'll have to forgive my metalworking ignorance, as its been 20 years since I've done anything like this!

during metalwork class at school, we were shown how to make a flat edge on a piece of metal. engineers blue was spread on a engineers reference flat, then the edge of our work piece was placed on it and the dye transfers onto the high points on the edge of our work piece, which then needed to be filed down. This is how I was taught how to make an edge flat.

What I'd like to know is, where I can get one of these ' engineers reference flat' plates from?

How much are they?

Also, what are they called? As I've googled every term/phrase I can think of.

Is there a better way of making an edge flat?

Thanks for your help, Richie

 

[Paul.]

I think your looking for a surface plate, look here

 

[Archie]

God. All sounds frightfully technical. I was taught to hold the edge of a metal ruler up to the side in question. If you could see light anywhere then the parts touching the ruler needed filing. Once you had one surface done you used that as the datum. Only things I can think of (other than a datum table) that might match your needs are ground stocks. Come in bars but available in squares here. May have got completely the wrong end of the stick though!

 

[snowcat]

Yep as Archie says ground stock bar is the kidy your looking for, personally I call it witnessing, but I'm not sure if thats just yokel speak.....

 

[zardoz]

i often see them on ebay, from small 200mmx200mm to 18x12x3 inch blocks, to entire solid table tops. Bowlandtrading (factory closedown sell off firm) often has them.

At a pinch, a thick piece of glass will do the job.

 

[English Steve]

The Engineers Blue is available from Frost, and as TIGPaul said is used with a surface plate or surface table.
Spent many hours as an apprentice filing a piece of 1/4 bar down to 6mm, which had to be flat both sides. We had to measure it with a pair of outside callipers and a steel rule, and get the thickness within 10thou The training officer then divided the surface up into squares and measured them with a micrometer - any that were outside of tolerance had to be done again.
Turned mine into a drill drift afterwards

 

[Richie]

Many thanks for your quick replies!

It's a surface plate I was after - now I know what they're called!!

I could use ground stock for my projects, but I wanted to do it by hand to give me some sort of 'skill at hand'!

I've been using a mirror up till now but I'll treat myself to a granite surface plate!!

Once again thank you for the advice, Richie