Cast Iron is just as subject to internal stress as any other material. Especially freshly cast iron. However like a lot of castings iron will age and stress relieve over time. Locally some of the old tool manufactures would literally throw the castings outside for the winter to allow the extreme temperature changes to accelerate release of stress.
So don't assume that stress isn't there in cast iron. It amy behave differently than cold rolled for example but it can cause you grief. The older the casting the less residual stress and thus why some people make straight edges out of old ways. It is also why buying an old machine that is in good condition is often a good idea.
Dave
On Jan 1, 2011, at 11:10 AM000, Ron Thompson wrote:
> On 1/1/2011 10:27 AM, Rick Sparber wrote:
>>
>> Now that I think about it, maybe it is HRS. I had forgotten about CRS's
>> warping problem but wonder how bad it would be if I am only removing a few
>> thou of material. If the stuff doesn't behave, it will still be useful for
>> other projects. Clearly I must first see if I can make a straight edge
>> before spending time making a pair of squares.
>>
>> Rick
>>
> I'd try a chunk of cast iron. You can buy it in pieces.
> How about this:
> http://www.speedymetals.com/pc-4254-8387-1-14-x-2-14-gray-cast-iron-class-40.aspx
>
> Or you could try weights from Walmart.
>
> --
>
>
> Ron Thompson
> On the Beautiful Florida Space Coast, right beside the Kennedy Space Center, USA
>
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>
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>
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> http://www.plansandprojects.com/My%20Machines/
>
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> http://castinghobbyfaq.bareboogerhost.com/
>
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> [Non-text portions of this message have been removed]
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