Pink Granite Block

Some years ago I worked in a very large shop. I was just a bridgeport hand at the time. Anyway the shop closed down and I was one of the last people
to be let go. I got to leave with many things I thought may be useful to me.
Material, tooling, some machinery, odds and ends of stuff.

One of the things I got is this hunk of Pink Granite. It is about 12" square and 8" thick. It is finished smooth on 4 sides and what I would call rough sawn on 2 sides. The 2 rough sides are the 8" dimension.

I took it because I found it "neat". You know, the same stuff that some of our very large surface plates were made from. I had no real use for it, so I gave it to the wife to put in her garden.

I am still in the trade and since the time I got it, I have come to hear of "Granite Squares", tho I have never seen one, but now I wonder if this is what I have. If so , is it still any good after sitting thru 4 or 5 years of Michigan weather? Presuming it was any good to start with. There are some small dinks in it.

Anyone care to speculate ?

Thanks,
Kerry

pink granite

I have never seen a granite square that shape...BUT...

If after a good cleaning 2 sides are parallel within tenths you have an excellent granite parallel.

That being said if you place it so the 2 parallel sides are vertical, and you place a surface gage against a side and set an indicator at zero touching near the top....then without changing the indicator you approach the other side, touch and the reading is still zero, you have a granite square probably within tenths of thousands.

It's been outside for 6000 yrs on the concervative side eh?


-------------

Think Snow Eh!
Ox

Thanks for the info.
I guess I will pull it in come Springtime and check it out.
Wife will most likely give me hell if I take back tho.

So get it sawn into 4-2" slabs and give her 3 of them.

I know for HUGE surface plates, Starrett made legs out of granite.
I wish I could remember where in Michigan I saw them years ago... Focus: Hope maybe?
Anyhow, that piece you have might be a part of a surface plate base.

This is a reference block.

The faces are finished square and parallel to a very tight tolerance.

It's used to set square references, like spindle to table and such.

For example, set one finished face on a mill table. Mount a dial test indicator in a collet with the needle against another finished face, then move the dti up and down with the quill handle. This enables you to adjust the spindle perpendicular to the table.

- Leigh