Measuring wear on a surface grinder

I've been practicing with my 540 now I have it running. I'm posting this here rather than a new thread as I think the outcome shows I don't have any significant wear on the machine.

I also don't have a master square, so I thought I could make one using 3 import squares - matching each one to another in round robin.
To do that all I needed was a flat flat. Seems like a grinder would be a way to make one of those...

I have assorted scrap waiting to be turned into new things.
In the pile is an old clutch pressure plate - a reasonable lump of old cast iron.
I hacked it into 3 pieces:

Then used my mill to make them 'mostly' straight:

(anvil for scale )

I also made them roughly the same height, and cut a small flat on the curved edge.

Then bunged them onto the grinder:

Taking care not to add heat I proceeded at around 3 thou DOC / 150 thou stepover. 46 K SG wheel.

Turned out nice:

And blackout flat:

All 3 match with no light, and blue against each other really evenly.
Think that shows my grinder doesn't have significant wear.

Next I need to learn how to grind square and arbitrary angles. (tips gratefully received)

Dave

Certainly look in a lot better nick than my little Herbert Junior when it arrived.

i don't know if you have a Facebook account , but there's an ongoing album here, which should be set to public viewing, each photo has a basic description of what I'm up to.
Eventually I'll duplicate the album to Flickr, and add some of the content on this forum, but obviously not on your thread.
The column itself was slightly bowed, as well as the main dovetails showing wear in the middles, so the knee rocked in two different dimensions.
The table showed the same banana tendencies, as do the cross slideways.
I could maybe have used it to grind a lens, thou it may not have been optically very good.