# i have a question



## Ulma Doctor (Mar 9, 2013)

most of my work is done on site in primitive conditions for machine health. 
i'm called on to make set ups on site and perform operations that would best be left to a better equipped facility.
i have to do a lot of stuff on the fly as it were...
my question is this, how can i make or get a light weight surface plate accurate to .015+or- to take with me... the kicker is i need to be able to set up and accommodate 12X12 +- pieces for versatility..
any suggestions? 
i'm thinking of a three point footing to start with....:thinking:


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## Richard King (Mar 9, 2013)

How about a 12 x 12 granite surface plate.   I have a 18" x 18" that I carry with me when I travel to a shop to scrape ways on a worn machine.  The plates come from the manufacture in 3 points.  I bet you knew that already?    + or - .015"  ??  You must have had a typo.  Did you mean .0015 or .00015".  As this grade B is .0001".  Weights approx. 80 pounds.   

http://www1.mscdirect.com/cgi/NNSRI...re=ItemDetail-_-ResultListing-_-SearchResults



Item Number63324107BrandValueLength (Inch)12Width (Inch)12Thickness (Inch)3Number of Ledges0GradeB (Shop or Toolroom)TypeInspection Surface PlateOverall Unilateral Flatness Tol. (Decimal Inch)0.000100MaterialGraniteColorBlackBig Book Page #1830Metalworking Catalog


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*Price: $81.85 ea*


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## Ulma Doctor (Mar 9, 2013)

thanks for the info, i was looking for something in the 40 lb range is my issue
i carry a lot of tools in weight is a major concern, accuracy is not the greatest concern .015' was a typo...ooops
i usually have a little slop,  .005"in 12 inches is acceptable for my stuff in most cases.


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## n3480h (Mar 9, 2013)

Here ya go, Mike:  I think this is a 9 x 12 x2" plate  http://www.woodcraft.com/PRODUCT/20...ode=10INGOPB&gclid=CPjoxqGK8bUCFcZFMgodUBsAdg

I bought their 12 x 18 x 3" surface plate through Amazon and I am very happy with it.  Not sure what method they are using to grade their plates, but mine is VERY flat.  Good prices and rediculously low shipping cost ($10 for mine). It arrived pretty quickly and the plate was in a fitted plywood box, inside a fitted heavy corrugated box.  No damage.

Tom


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## Lignin (Mar 12, 2013)

Hi,

My background is more in woodwork, which is where my suggestion comes from.

How about a granite torsion box? Think of this as two slim granite tiles, both surfaced each side and parallel, spaced apart by 1" tall, slim granite 'ribs' in a 'noughts & crosses' (tic-tack-toe?) grid arrangement.

If you are aiming at three legs, then perhaps make the plate triangular(ish) to prevent topple; since it will be relatively light.

Knock up a thin, rugged, plywood case and line with polyurathane foam for protection in transit.

I've almost inspired myself to make one!

Good luck


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