Where are the very fine AlO2 wheels hiding?

[aphexafx]

I've been looking everywhere online, and off, for a super/extra/very fine grit aluminum oxide 6" x 3/4" (or 1") grinding wheel, which should be around 120 grit. The best I can find is a fine wheel at 100 grit. It seems that when the grit goes smaller than 100, the wheels become silicon carbide, or whatever, and I was told to not use that type of wheel once, very strictly.

Does anyone know where to get a 120 grit (extra fine) AlO2 wheel?

And on this topic, for those of you who use bench grinders to prepare your tungstens, what do you all use? Does anyone prepare using only AlO2 wheels, if so what grits do you use? Or does everyone use diamond wheels?

(I searched for this but couldn't come up with anything conclusive...so if you're sick of this question I apologize in advance. )

[Johnp]

Grizzly has some 1 1/2" wide wheels. I just ordered one to try. Part number G7416 is a 6" 120 grit aluminum oxide. Hope this helps.

John

[Leons2003]

I'm using an Alo2 60 grit @ 2000 rpm that was provided w/the new 6" b.g. I recently aquired.
Good luck
L*S

[Mike W]

Enco or MSC should have them. Also McMaster Carr.

[aphexafx]

Thanks for the suggestions, guys! Things are looking better.

leons, I can get a pretty good finish on the taper with a 6" A60 wheel, but I can't get clean flats. I figure that with a 60/120 combination I can get much smoother tapers and cleaner flats.

Has anyone tried the pink aluminum oxide wheels? They apparently are similar to the white bond wheels but are less friable and don't groove as quickly. Anyhow, they are readily available at 120 grit.

[HAWK]

aphexafx,

Aside from faster degradation what is the problem w/ silicon carbide wheels?

[aphexafx]

Well, frankly, I don't know from first hand experience, but I was told by someone I went to with questions (before I found this forum) that you shouldn't use them (silicon carbide) because they will contaminate the tungsten. I've wondered about this ever since, and I even saw someone else mention the same thing here, but I've always just thought to stay away from them.

Is this not true? I just spent about a half hour looking for the post that mentions not to use a silicon wheel to no avail. Perhaps I didn't see it here.

Hmm... So, silicon carbide is OK?

P.S.> I must have missed some of the grinding posts in my earlier search because there are a lot of them and some of them talk about this same this in some way. So, once again I apologize for making yet another post...but I did and it's too late. Thanks for all the help anyway.

[aphexafx]

I think I'm going to order a pink AlO2 and see how well it works out. It sounds like the perfect wheel for tungsten prep. based on available grit sizes and bond characteristics. It's a little pricy, so I'll see how long it lasts...

[paulrbrown]

aphexafx, hey, I use zirconium belts and disks to grind tungsten, I save the silicone carbide for carbide tools, but have used it at times with no problem. The big concern is cost,silicon carbide is more for hard materials because it fractures easier and is always exposing new sharp grains. Tungstens are hard!!!! so other than cost, why not???? They use Diamond on the high dollar jobs don't they, and they are the hardest...Hope this helps, Paul

[Blown S-10]

what do you mean by "clean flats" ?

[aphexafx]

I just mean that when I need to put a flat on the tips of my tungstens, it's really hard to do with an A60 wheel - it's like it's knocking the tip off as opposed to grinding it away, and they are never very smooth or even. Since this is where the arc is going to plant itself I want them uniform and smooth (= "clean" )

Now usually I can avoid this by pre-grinding a large flat and then tapering down to the flat diameter that I want...but not always.

This is all arising because I ordered some preground and WOW they're smooth and beautiful. I just want to up my grinding capability and skills...so I want a finer wheel. Oh and I want to try to do it without buying a diamond wheel.

paulrbrown, I'll be the first to admit that I'm not a great grinder and I probably don't know much about what I'm talking about, but I've never liked the really friable wheels that wear down so fast (even though I understand that this keeps them sharp). I have a harder time getting a clean grind with them - but perhaps I need to work on that?

[HAWK]

aphexafx,

The preground tips are slick! The ones from Diamond Ground are ground with the aid of CNC machines. I am working on reproducing the high polish finish of these CNC ground tungstens during the after welding touch up process. I think it is working, but have had no real success with a bench grinder-even with my diamond wheel. Don't get me wrong the grinds are really good with the bench grinder. They are just not comparable to the high polish of the original product. That is what I am striving towards.

[aphexafx]

Don't get me wrong the grinds are really good with the bench grinder. They are just not comparable to the high polish of the original product. That is what I am striving towards.

Oh yeah, you'd have to be pretty [email protected]&# good with a bench grinder to get that kind of finish! Just curious, how close do you get to the CNC pre-grounds with your Piranha?

[Blown S-10]

I just mean that when I need to put a flat on the tips of my tungstens, it's really hard to do with an A60 wheel - it's like it's knocking the tip off as opposed to grinding it away, and they are never very smooth or even. Since this is where the arc is going to plant itself I want them uniform and smooth (= "clean" )

Now usually I can avoid this by pre-grinding a large flat and then tapering down to the flat diameter that I want...but not always.

This is all arising because I ordered some preground and WOW they're smooth and beautiful. I just want to up my grinding capability and skills...so I want a finer wheel. Oh and I want to try to do it without buying a diamond wheel.

paulrbrown, I'll be the first to admit that I'm not a great grinder and I probably don't know much about what I'm talking about, but I've never liked the really friable wheels that wear down so fast (even though I understand that this keeps them sharp). I have a harder time getting a clean grind with them - but perhaps I need to work on that?

:disclaimer: my idea of a good grind "maybe" be different than yours.

my grinds turn out pretty well, i think. i use a fine wheel, $7.00, H/D. the face is used for ROUGH grinding, get the junk off. the right side is for shaping, get the basic shape, tungston pointed "away" from rotation, lower side of grinder shaft. the left side is for final shaping, dressing it to its point, the tungston is pointed "INTO" rotation, upper side of grinder shaft..
the flat is done on the right side, after most of its rough shaping, while turning it. ""THEN"" final shaping is done. this removes the burrs.

if this description doesn't make sense, ask for pics.

[aphexafx]

Wow, thanks Blown S-10 I'll give it a try, sounds good. You're talking about doing all of this on one wheel, right? When you're dragging the tungsten for rough shaping below the shaft (right side) and grinding the tungsten for final shaping above the shaft (left side), what area of the side of the wheel do you...eh...employ, I guess?

So [and this is stemming from High School shop class saftey films] as long as I watch the groves on the wheel sides and be smart about it...it won't suddenly stress fail and explode voilently at high velocity, maming me and those near? In the early days of shop they had us believeing that if you even glanced at the side of the wheel it would kill you instantly.