Old rebuilt jaw crusher from Boulder Col. help and use thereof.

[Mad Machinist]

Hello
Got most of a all aluminum trailer that is 2 x 4 feet in size built to put the crusher on. Also turned the shafts for the rolls say 3 - 6 thousands over size.

Industry standard is .0005 to .001 thousandths per inch of shaft size. So if your main shaft is 2 inches in diameter you should have .001 to .002 thousandths oversize on the shaft.

EDIT AS FOLLOWS:

I had to jump on my laptop as it is easier to type this out. The thermal expansion coefficient for steel is .00000645 per inch per degree F. So if you have a 2 inch shaft for the rolls with .006 interference fit, you would have to heat the roll to 500+ degrees in order to get it together.

2 x .00000645 = .0000129 x 500 degrees = .00645" expansion

The problem with this is most steels start changing properties at around 400 degrees. Most likely heating the rolls to 500 degrees would anneal the steel and make it softer.

So if you follow the industry standard of .0005 to .001 thousandth per inch of shaft size you would end up with:

2 x .00000645 = .0000129 x 200 degrees = .00258" of expansion.

If you stay to the smaller side of the industry standard (.001 to .0015), this would fall right together and WILL NOT come apart without specialized tools and a rosebud to reheat the roll.

By the way, an old gas stove oven works great for heating smaller parts to fit them together. Change the natural gas orifice to a propane orifice, buy a gas grill regulator at your local hardware store, and you can use barbeque grill tanks to run the oven so your significant other doesn't murder you. Put the part in, set the temp, and let it slowly soak up the heat for a couple of hours.

Isn't being a mine millwright fun?

 

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[Assembler]

Industry standard is .0005 to .001 thousandths per inch of shaft size. So if your main shaft is 2 inches in diameter you should have .001 to .002 thousandths oversize on the shaft.

EDIT AS FOLLOWS:

I had to jump on my laptop as it is easier to type this out. The thermal expansion coefficient for steel is .00000645 per inch per degree F. So if you have a 2 inch shaft for the rolls with .006 interference fit, you would have to heat the roll to 500+ degrees in order to get it together.

2 x .00000645 = .0000129 x 500 degrees = .00645" expansion

The problem with this is most steels start changing properties at around 400 degrees. Most likely heating the rolls to 500 degrees would anneal the steel and make it softer.

So if you follow the industry standard of .0005 to .001 thousandth per inch of shaft size you would end up with:

2 x .00000645 = .0000129 x 200 degrees = .00258" of expansion.

If you stay to the smaller side of the industry standard (.001 to .0015), this would fall right together and WILL NOT come apart without specialized tools and a rosebud to reheat the roll.

By the way, an old gas stove oven works great for heating smaller parts to fit them together. Change the natural gas orifice to a propane orifice, buy a gas grill regulator at your local hardware store, and you can use barbeque grill tanks to run the oven so your significant other doesn't murder you. Put the part in, set the temp, and let it slowly soak up the heat for a couple of hours.

Isn't being a mine millwright fun?

Kinda figured some thing like this. Will have to get the pillow block bearings and measure then turn the shafts some more. Thanks for the tips Mad Machinist.
Sure is a long process just to go out and crush some rocks.

 

[Assembler]

Hello
No wonder there is less people going out on a small scale to crush some rocks as it seams that one need to know how to weld, machine and hand build at the very least. However one can get a China impact mill and get started that way. There is a lot less time spent as well buying from China.

 

[hvacker]

Like Mad said about babbit they have an advantage of being self healing. They are still commonly used today.
While not completely keeping the shaft from wear (Think early Chevy six cylinder ) they are soft and that's the intent.
If memory serves the clearance on those Chevy rod and main bearings was .002. In any case the clearance could be
looked up.
You might know but in case there is a product called Plastigage. It's placed between the bearing and shaft.
Torqued down and the compression thickness is read with a micrometer. Some use soft solder to
do the same thing.

 

[Assembler]

Like Mad said about babbit they have an advantage of being self healing. They are still commonly used today.
While not completely keeping the shaft from wear (Think early Chevy six cylinder ) they are soft and that's the intent.
If memory serves the clearance on those Chevy rod and main bearings was .002. In any case the clearance could be
looked up.
You might know but in case there is a product called Plastigage. It's placed between the bearing and shaft.
Torqued down and the compression thickness is read with a micrometer. Some use soft solder to
do the same thing.

Thanks for the ideas.
If this one was to do it over mite have considered replacing the babbit bearings. The babbit wear a lot faster then brass and tin.

 

[Assembler]

Just for fun.

Hello
Just for fun will have to put some stickers on the back of the trailer for the crusher........LOL :