# Surface plate question



## Markinfargo (Apr 26, 2018)

I'm planning to add a surface plate to my shop.  I'm curious about temperature effect on the plate.  I'm in North Dakota,  my shop is my unheated garage.  Maybe I'm missing something, but what I've been reading understand as the temperature extremes that are in my shop will basically destroy the surface plate.  Am I missing something? The shop I used to work in wasn't very well temperature controlled, and the surface plate there seemed to be fine,  but then again, I didn't need to use it very often. Ideas? Recommendations?


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## benmychree (Apr 26, 2018)

The temperature will not hurt them, but possibly it may not be as accurate in terms of flatness or overall tolerences; in a hobby shop, it does not matter, I don't think you could tell any difference in ordinary work.  You do not state whether or not you are talking granite or cast iron, if iron, you'd want to keep it oiled to prevent rust, I use a very oily rag under a wood cover on mine.


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## Markinfargo (Apr 26, 2018)

I intentionally left out the granite and cast iron comparison as both are viable options at this point.


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## benmychree (Apr 26, 2018)

Personally, I prefer cast iron plates, they are much lighter than granite, and I think that tools slide on them easier.


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## projectnut (Apr 27, 2018)

benmychree said:


> Personally, I prefer cast iron plates, they are much lighter than granite, and I think that tools slide on them easier.



My experiences are a bit different.  Last year I was in the market for a 24"x36" surface plate.  I looked at both cast iron and granite models.  In most cases the cast iron models were heavier.  I ended up purchasing a 24"x36" Challenge brand plate.  It weighs in at 475 lbs.  The same size granite ones were between 410 lbs. and 440 lbs.


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## benmychree (Apr 27, 2018)

I have a 24 X 24 cast iron plate that I can easily pick up and carry, try that with a granite plate ---


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## projectnut (Apr 27, 2018)

benmychree said:


> I have a 24 X 24 cast iron plate that I can easily pick up and carry, try that with a granite plate ---


I'd be interested in knowing what brand surface plate you have.  I'm guessing it's not a Challenge brand.  The 24"x24" Challenge cast iron plate weighs 325 lbs.

http://www.challengeprecision.com/products/plates/threepoint.htm.

Their Granite plate of the same size weighs 275 lbs.

The same size Granite plate from the CNC specialty store only weighs 216 lbs.

https://cnc-specialty-store.com/mea...MIuOq4he3b2gIV1xKBCh2dDwoxEAAYASAAEgJrKfD_BwE

One from Grizzly weighs 234 lbs.

Even one from Starrett only weighs 220 lbs.


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## benmychree (Apr 27, 2018)

projectnut said:


> I'd be interested in knowing what brand surface plate you have.  I'm guessing it's not a Challenge brand.  The 24"x24" Challenge cast iron plate weighs 325 lbs.
> 
> http://www.challengeprecision.com/products/plates/threepoint.htm.
> 
> ...


I looked and did not see an obvious brand name on it, but will perhaps look again tomorrow and take a picture; the top is 1" thick, and the height including the top is 5 3/8".


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