Expectations of a granite surface plate ...

[DaveH]

(03-06-2012, 03:48 PM)ETC57 Wrote: Ok so why when I take a crew out to install a rather large (4'x8') surface plate in R&D type shops the customer always make me get out the machinist level?

Jerry.

The customer wants it level. Like arvidj has indicated it can be useful to know that it is level.

For inspection purposes the surface plate is nearly always set level and checked often.


DaveH

[ETC57]

(03-06-2012, 03:56 PM)DaveH Wrote:

(03-06-2012, 03:48 PM)ETC57 Wrote: Ok so why when I take a crew out to install a rather large (4'x8') surface plate in R&D type shops the customer always make me get out the machinist level?

Jerry.

The customer wants it level. Like arvidj has indicated it can be useful to know that it is level.

For inspection purposes the surface plate is nearly always set level and checked often.


DaveH

So it's have your cake and eat it to!

Jerry.

[arvidj]

(03-06-2012, 03:51 PM)DaveH Wrote:

(03-06-2012, 03:44 PM)arvidj Wrote: I understand the difference between level and flat.

No apology necessary.

I think you may have taken the tone of the message incorrectly … i.e. is was not intended to sound like your wife telling you what she knows when you try to explain something to her… just me stating a fact and then an example of what I was wanting to do ... but obviously will not be able to accomplish.

[doubleboost]

Hi
I have had a large piece of marbel in my shop for months now
I had to move it and it broke
I now have a piece 24 inch by 16 inch
Checking it for flatness i found it to be well within 1 thou (plenty good enough for what i do)
I have a 8/10 ground iron plate but this is a bit small for the stuff i make
John

[DaveH]

(03-06-2012, 04:50 PM)doubleboost Wrote: Hi
I had to move it and it broke
John

John
You mean you dropped it

DaveH

[doubleboost]

Funny that is what the wife said
It was 6 feet long 18 inches wide 1 1/2 inches thick stupidly heavy and millions of years old
I was going to blame the plumer but did not have the heart to
John

[DaveH]

(03-06-2012, 04:56 PM)doubleboost Wrote: It was 6 feet long 18 inches wide 1 1/2 inches thick stupidly heavy and millions of years old
John

John,
Good job it was an old one then,

DaveH

[stevec]

Arvid, I hope your questions have been answered, Sometimes the jocularity obscures the legitimacy.
You've had one reply that "One side will be ground flat and the other is usually kind of rough."
Is your plate like so? (I doubt you would have asked the question if it were blatantly obvious).
The other point of parallelism you've answered yourself and I agree.
So, to reiterate, because I'm curious, are some surface plates ground to the same flatness and surface precision on both sides?

[ETC57]

Steve,
to answer your question from my experience some of the plates I have installed have been finished on both sides

Jerry.

[doubleboost]

Hi
I think it would be a good idea to have both surfaces ground
If one surface gets damaged it could be turned over and the other side used.
John