grinding magnetic parallels

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skipd1

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I finally got my 6x12 Walker magnetic chuck ground and I have some used 1"x2"x8" magnetic parallels I would like to clean up. I have checked them and they are all fairly the same size (within .004") in height and width. I would like to clean them up an make sure they are the same thickness and height by grinding them on my Harig 6x12 grinder. I am currently using a Norton 46J grit 6"X1" wheel. Because they are steel plugs in an aluminum block I have some concerns grinding the aluminum. Is this possible and if so what concerns should I take?
Thanks

Skipd1
 
You can grind aluminum but if you don't know what you're doing, you can run into trouble. Aluminum clogs the wheel, expands, and can cause the wheel to shatter: safety issue.

Normally, aluminum is ground with an "open" silicon-carbide wheel. Unfortunately, Silicon Carbide isn't the best for grinding steel where aluminum oxide wheels are the norm.

I've seen guys grind aluminum using a ceramic aluminum oxide wheel (Norton 5SG type - also very pricy!) if they first lube the wheel up with a wax-like substance called Boelube. Whether it's a good idea or not I can't say, but it did work!

John
 
Nobody should be giving advice on this subject because it does carry a slight risk of danger. I didn’t say this, but your Norton 46J wheel should do just fine. Coarse dress it with a sharp diamond. When grinding, take light passes. Use coolant. Check the wheel every thou or so. Since you are only taking a few thou off, not doing this all day for a big job and it’s not all alluminum, you should be OK with said wheel…Good Luck & Be Safe.
 
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chips&more said:
Nobody should be giving advice on this subject because it does carry a slight risk of danger. I didn’t say this, but your Norton 46J wheel should do just fine. Coarse dress it with a sharp diamond. When grinding, take light passes. Use coolant. Check the wheel every thou or so. Since you are only taking a few thou off, not doing this all day for a big job and it’s not all alluminum, you should be OK with said wheel…Good Luck & Be Safe.
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Well said Chips! Maybe that's the trick...

If the wheel doesn't clog with aluminum, then it won't break - hopefully. So, maybe frequent checking and redressing is the way to go.

That said, I agree the technique is not without risk. Be careful!

John
 
chips&more said:
Nobody should be giving advice on this subject because it does carry a slight risk of danger. I didn’t say this, but your Norton 46J wheel should do just fine. Coarse dress it with a sharp diamond. When grinding, take light passes. Use coolant. Check the wheel every thou or so. Since you are only taking a few thou off, not doing this all day for a big job and it’s not all alluminum, you should be OK with said wheel…Good Luck & Be Safe.
Click to expand...

Nobody should be giving advice? Seriously? Just because something is technical we should refrain from helping? Does that mean we can't give the advice that this carries danger?


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nmasi said:
Nobody should be giving advice? Seriously? Just because something is technical we should refrain from helping? Does that mean we can't give the advice that this carries danger?


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Click to expand...


This is The Friendly Machinist Forum. The edit button allows you to edit for 24 hours after you post.
 
Enough of the safety nonsense.

If you are smart in the shop, you expect everything to wrong at every possible time. Including surface grinder wheels breaking. ALWAYS expect them to break, no matter what your doing. So when one does break, your prepared for it. Meaning head, and hands are away from the line of fire and you won't get hurt.

With that said, grind away. Check the wheel for clogging and dress often. Make sure the aluminum doesn't get hot either since it gets gummy when hot.
 
Enough of the safety nonsense.

If you are smart in the shop, you expect everything to wrong at every possible time. Including surface grinder wheels exploding. ALWAYS expect them to break, no matter what your doing. So when one does break, your prepared for it. Meaning head, and hands are away from the line of fire and you won't get hurt. A surface grinder wheel exploding can be dangerous, but it's not if your prepared for it and wheel guards are on. I'm not a fan of guards on machines, but unguarded wheels scare me in case the wheel goes.
 
As long as a Caveat about the safety implications are clearly included in the advice I see no problem with giving said advice. However, that being said we do have a large number of beginner machinists who need to be aware of the possibilities of and to be prepared for the worst possible event, like Andre' said. Any machine with a rotating wheel should be treated with absolute respect and deference to avoid getting a serious injury. Or even worse losing an eye or finger. Let's all try to remember that the "Friendly" part is very important and there are many different ways to pass on info without sounding like you are talking down to or belittling another. Let's all just keep that in mind going forward please.

Bob
 
We always used a 46H with lots of paraffin wax forced into the wheel as it keeps it from loading up.

When you start getting gouges into the aluminum when grinding, you've waited too long to redress and reload the wheel with paraffin. It takes a bit of experience to know what to listen and feel for, but you'll get it soon enough.

We used to get the paraffin in block form used for making candles or canning foods.

Just another trick to try out as it works very well, but it is messy!

Dave
 
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