Hot Rolled vs. Cold Rolled

[RegionalChaos]

Howdy,

I recently stumbled across some plans for building a 2x72 inch belt grinder. Basically a KMG clone. The material list for the machine specifies cold roll material. It is decidedly easier for me to find scrap hot roll. Will using hot roll instead of cold roll really make a difference? I did some initial research, and it kind of seems like I should be fine with hot roll, but I thought I would ask. I know cold roll should be a little harder, or more rigid, but will it make that much of difference? I thought another reason they say cold roll might just be the appearance..

Thanks!

[skunkriv]

Hot rolled can vary in actual size. Cold rolled is held to much closer tolerances.

[HWooldridge]

Originally Posted by skunkriv

Hot rolled can vary in actual size. Cold rolled is held to much closer tolerances.

Correct - for example, 1/2" HR will be somewhat larger than .500 and very likely not round but a bit egg-shaped in cross section.

[Dodge]

I too, agree that cold rolled will give better tolerances. However, if the tolerances are something you are able to fudge a little, or perhaps provide a bit of shimming, (sliding parts etc.) hot rolled should work for most purposes that call for mild steel. A lot depends on a persons individual skills and knowledge of mechanics. If you are comfortable with making minor modifications to a design, go for it! "Improvise, adapt, and overcome!!"

[RegionalChaos]

I wouldn't think the tolerances would make that big of a deal in the application I am thinking about. Dodge, didn't you just build a belt grinder? Did you use hot rolled or cold?

[Dodge]

Most of my grinder was tubing. The pivot that allows the belt to be used at different angles is a tube within a tube. There really weren't any tolerances to hold as there is in a sliding design like the KMG

[Ten Hammers]

OK my nickels worth. I never buy cold rolled unless I need a shaft to fit a bearing or a really tight nice fit to precision tubing ( or when something is not available in hot rolled ). Hot rolled is cheaper and has always met my needs. I will also say that hot rolled sheet lacks sometimes in quality ( new steel today ) and I do buy cold rolled in that regard.