Grinding of NON fer

One thing I have seen that is very disturbing from some of the gun builders web sites from this forum is, the use of dremmel tools or simular tools , being use to grind
NONFERROUS MATALS. :nono: :shake:

Ferrous metals contain iron, which is ok to grind. :thumbsup:

Nonferrous metals are brass, copper,lead,aluminum, ect.

NON FERROUS METALS SHOULD NEVER BE GROUND WITH ANY TYPE GRINDING STONE!!!!!!!!!!!!!!!!!!!!!!!! :nono: :shake:
IF it doesn't spark when you gring it, DO NOT grind it.!

The reason being is the grinding stone gets full or pluged with the metal ,(such as brass ) and this will cause the stone to heat up and BLOW APART!!!
The dremmels are high speed tools and the more RPM's the more heat it will create in the tool.

While I was in the military I seen first hand what happens
when one of these wheels or grinding stones flys apart.
Trust me it is not a pretty picture.

Please be carefull and never grind these metals, even if you have done so in the past and nothing happened. Consider yourself LUCKY!

Be Safe
Woody

 

[TexasMLer]

Well, I'll be darned! That explains it! I have first-hand experience with what you are describing.

I had two grinding wheels (the two that come with the dremel)explode right in my face when I was grinding a brass wedge plate. I assumed that I was using too much pressure when the first wheel exploded so I used much less pressure when using the second wheel. It exploded as well. I have not had a grinding wheel break since. Makes sense, because I haven't grinded any brass since.

The good news is that the wheels COMPLETELY exploded leaving just grinding wheel dust behind. There were no pieces large enough to do any damage, thankfully.

Thanks for the information! :thumbsup:

 

[Zonie]

If you feel you must grind non-ferrous materials with a grinder, one method which won't cause the wheel to break is to use a sanding drum.
These are available for hand held high speed grinders. The drum size is 1/2 dia and the sand paper replacements come in course, medium and fine. A certain company that starts with D wants an arm and a leg for the replacement sandpaper. Places like Ace sell replacement sandpaper for a much more reasonable price.

I have never had a problem with these. Of course you have to replace the sanding material often because, as the original post mentioned, they fill (load) with the soft metal and quit working.

Don't get lazy when grinding ANYTHING. Put on your safety glasses. You only get one set of eyes so take care of them.

 

I saw this happen to a guy who was using a bench grinder. It was a long time ago when I worked for US Steel in the Pittburgh area. The foreman had just told him to file the part, don't grind it because it was a brass fixture and the wheel would explode. That was a hard lesson for that young man and for us other young men who were in the "blast area".

 

[Ashby]

Now Woodhick this is certainly good advice and a carbide burr or similar cutting tool would be a better choice for working with non ferrous metals however for the stubborn out there there are some techniques that can make this operation safer (I am not saying safe just safer).

The important issue is to not let your grinding wheel build up. Soft materials such as brass or aluminum will fill the areas between the bonded grit (that is the grinding wheel) this is what causes the heat to build, the cutting to stop and the pressure to build. If you can take a light chip and dress the wheel often this operation can be done safely. I have ground large plates of aluminum with success by simply keeping a light touch and a well dressed wheel.

The best advice has already been offered, use another technique but if it a small edge you are trying to soften or some other light duty work an open grit, soft, sharp wheel can be carefully used. :results: :m2c:

Feel free to disagree :shake:

 

[uncrichie]

Is it the heat alone or a combination of that and excess metal loaded onto the wheel causing it to be unbalanced? Uncrichie...

 

[Metalshaper]

Woodhick,

Your warning is a good one and certainly appreciated!

I wondered about something.. and maybe you can tell me different. Since my shop has very few machine tools, I do most of my work by hand.. and because of this I look for and read any old shop manuals and articles that I can find.

With that said,, I read in an old Popular Mechanics "Shop notes" < think the vintage is 1950's> to grind non-ferrous metals..load the wheel first with a bar of soap! The soap is supposed to lube the grains of the wheel and prevent the build up of the softer metals..

So, what do you think,Yea or nay?? or would anyone want to try it??

Just wondering :hmm:

Respect Always
Metalshaper

 

[scott k]

With that said,, I read in an old Popular Mechanics "Shop notes" < think the vintage is 1950's> to grind non-ferrous metals..load the wheel first with a bar of soap! The soap is supposed to lube the grains of the wheel and prevent the build up of the softer metals..

So, what do you think,Yea or nay?? or would anyone want to try it??

I would say do this at your own risk. especally with a bench grinder. :imo: Deremels have a lot of good uses but when working with soft metals nothing beats a good set of files. When I went to school to learn the machinist trade the first thing you did was work with files. I think it's a lost art of sorts in this instant gradifcation age. It only looks slow. you can remove metal real fast with the right kind of sharp file. Faster with and with more control than a deremel :m2c:
Lehigh

 

[L.B. Myers]

Hi All,

Woodhick and others here have offered some very sound advice.

 

[bob1961]

had one do that too....but i did something that everyone might like....i made a sanding table for my dremel with a router attachment for the adjustment up and down and a sanding drum they make for it...........bob

 

Zonnie your correct when you say you can use a grinder by useing the sanding drum but remember these are not grinding stones. Much different.

Ashbey I stand by my first post....NEVER GRIND NONFERROUS METALS!
The grinding stones that these type grinders use is far to small to dress as you are suggesting. Even if a grinding stone is large enough to dress up , like a bench grinder type,,who is to say when to stop and dress.
If you choose to do so do so at your own risk.
IMHO it is exactly that a very dangerous risk.

Unrichie the heat could be part of it.as well as the build up of the noferrous meatl. Also i small piece may have be seperated from the stone already and you didn't notice it and this could also cause the unbalance in the tool.

I am not one to preach on what to or not to do.. But I have seen what an explodeing stone will do to a person and just warning you for you own safety and the safety of the people that may be near you if you choose to do such unsafe act.



Like zonnie said...always use safely glasses. Only takes a split sec to lose an eye.

Be Safe and keep that eye so you can sight that gun in when you get it finished. :winking:

Woody

 

[Ashby]

Well I was a bit hesitant to offer advice in this area as I do agree it can be dangerous. For many years I made my living as a tool maker and feel reasonably comfortable judging the need to dress a tool or the amount of pressure to apply. I also had a Carburendum stone or shop diamond available to dress with.

When I first learned the trade all the shops had tubes of wax to load the wheel similar to the soap Metalshaper describes. Never found it to be all that effective however.

The scothbrite or open drum sanding wheels work better than a 'mounted point' grinding wheel primarially because of the openness of the grit. Simply takes longer to load up. A fine file will load up quicker than a coarse one. Same principle.

Once again I am not disputing the validity of Woodhicks advice which is sound. Whaterever you choose be careful. Tough to get a proper aim with only 1/2 the eye sight. Let time take care of that!

Ashby :m2c:

 

[Terry Zboril]

Read Woodhick's post carefully.
HE IS ABSOLUTELY RIGHT.
A Grinding(stone type) wheel, is an ABSOLUTE NO NO for brass or aluminum!!!!!(unless you wear a Kelvar Jacket and eye protection, and can roll a seven every time!

Sanding wheels/Drums (sandpaper types), are a completely different animal. Sand brass to your hearts content.(still wear eye stuff, tho.)
Regards,
Terry