Sic vs AlOx belts

bodog

bodog

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On the Tru grit site they say AlOx belts are better for ferrous materials and sic is better for non-ferrous. For grinding hardened steel (sometimes high wear resistance, sometimes not) and shaping wood with the same belts, is one better than the other?
 
bodog said:
... is one better than the other?
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It's not as simple as that. I, for example, use the 3M tricact "Gator" belts which are a/o but made in a way that gives them good life and very even cutting. They are vastly different than the Hermes J-flex belts I also use which are a/o as well. I will say that I personally do not know anyone that uses s/c belts in knifemaking but, there are certainly makers using s/c sheets. Everything I use is either ceramic or a/o.

Bob
 
Why wouldn't they use sic? Any real reason?

I bought a handful of klingspor AlOx belts. Did I waste my money?
 
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No, usually you get your money's worth one way or the other if the belts are used for what they were meant for.
Bob, silicon carbide belts are really the only ones to use if working on mammoth tooth.
Frank
 
Frank Niro said:
Bob, silicon carbide belts are really the only ones to use if working on mammoth tooth.
Frank
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Frank, I've not worked with mammoth tooth yet, though I have a decent stash of it. What makes the s/c belts superior for tooth? It would be nice to not screw it up when I decide to use some.

Bob
 
I guess the size of the silicon carbide has a lot to do with how it cuts. Mammoth teeth often seem more like glass than anything else. Silicon carbide belts have a huge usage in the glass business. I recommend grits in 60, 120, 220, 400, 16 and then hand sanding to suit. If you buff be very careful you don't destroy the look you liked but thought might come through more. The often "rough ?"looking finish does seem to work with the material to make it look good. This is for me by far the most difficult material to work. When i start some work on mammoth tooth I known in advance it will be a challenge and actually look forward to it.
If you have any tips on drilling holes other than trying to pick a soft place in the scales please pass along. I still haven't found a way to do this that will every time provide clean holes. Epoxy and CA glue can often be used to help. The hollow diamond coated bits seem for me so far to be the best way to go although not near as good as I would often like.
Frank
 
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Silicon carbide is more friable, meaning it breaks down easier, exposing fresh cutting edges but wearing out quickly. It's very hard and sharp but doesn't hold up in steel very well. It's good in things like wood which won't fracture and refresh other types of grit and in things like mammoth tooth and glass that need a sharp cool grind.
 
Nathan the Machinist said:
Silicon carbide is more friable, meaning it breaks down easier, exposing fresh cutting edges but wearing out quickly. It's very hard and sharp but doesn't hold up in steel very well. It's good in things like wood which won't fracture and refresh other types of grit and in things like mammoth tooth and glass that need a sharp cool grind.
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So it sounds like aluminum oxide belts are probably the way to go for general use including hardened steel, wood, carbon fiber, and micarta. Do SiC belts have a lower likelihood of burning wood?

Are diamond belts worth the extra cost?

I see most people advocating for trizact belts rather than 3M or klingspor. Is there any reason, ie, grit stays on the belt longer, leaves more consistent finishes, etc?
 
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Well, a bit more then as I use. No, I definitely would not use silicon carbide belts for wood. Aluminum oxide will do a good job. For most steel either annealed or hardened I prefer ceramic and the engineered belts. So yes, my grinding may not be all that good but I do have some of each kind on hand and often in more than one belt stiffness.
Frank
 
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If you are grinding hardened steel you will probably want ceramic. They will last a lot longer and cut cooler. A medium step between the two would be somewhere around the Blue zircs from Norton. On hardened steel AO belts will wear quite quickly. I purchase ceramics and some zircs for steel and still buy the odd AO for handle materials and such. I also run the trizacts and find that they have excellent life if used properly, and they give a very nice even scratch pattern when grinding. For higher grit belts i find the trizacts pretty hard to beat dollar for dollar.
 
Guys
Performance aside, the main reason to shy away from siC belts is that the shattered grit if inhaled for long enough will cause Silicosis. So if you don't want to inhale the dust, not only do you need to wear a respirator while grinding, but you need to vacuum up all the grit in the shop.
Jim Arbuckle ABS JS
 
All the dust and particle crap is always a huge problem. I have had to put together another shop in a very confined area. This is my 5th and will be my last for sure. I have put together ideas for dust control and removal from the other 4 and am going with them at least to begin with.I hope to deal with what is necessary to be done for my particular situation.
 
bodog said:
Are diamond belts worth the extra cost?

?
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Yeah, in applications that dictate diamond. But otherwise no, it's expensive and diamond (carbon) literally dissolves into steel at grinding temperatures. Iron loves carbon like hot water loves sugar.

I remember reading an article about using diamond in steel. They addressed the problem by using an atmosphere rich in hydrocarbon. Acetylene perhaps? I remember it was something nutso. It was a pretty serious fire hazard (no oxygen could be present). So I guess you couldn't say never, but mostly never.

I've tried using diamond tooling here in the shop on steel in very hard steel applications. It wears away miserably. Steel is an application for CBN and other ceramics.
 
i should really start to place abroad my belt orders!!! Up today i had to buy the belts at my local vendor...the only 2 types are the blue belts and the brown ones but i have no idea what theose are made of ;) (the blue seems to cut better and last longer)
 
Just an opinion...

SC belts are rarely used in knife making. They just don't last. SC 9"x11" sheets for hand sanding are often used as they are available at any car body supplies place. They don't hold up well to hardened steel but they do make for a nice finish.

The belt that works best for you will depend on what speed you use it at, what metal (hardened or annealed), flat platen of contact wheel and the pressure you apply. One guy might have fantastic use and performance from one type of belt and the next guy can't get anything out of it like he's heard about.

In order for belts to stay sharp through their entire useful life, you have to break down the grit (friability like Nathan references) in use. Some grits are more friable than others. AO works great for wood, plastic, non-ferrous metals. They are cheap and generally don't load up like more expensive closed bonded abrasives. AO's are used all the time for metal work but they wear out quickly and turn out to be more expensive than say a zirc belt for metal grinding.

Ceramics work great at high speed, moderate to heavy pressure on hardened steel. It's the first thing I grab when I profile or to hog a blade out in a hurry. Hard and fast.
Zircs are in between AO and ceramic and you should try one to see if those fit your style.
Structured AO like Norax or 3M gator belts have some tech that make them great for finishing on metal. They aren't great for hogging but I'm sure some guys have great luck with that too. Both Norax and Gator belts like moderately high pressure/speed so they break down and stay sharp. Norax more than the gators. To "sharpen" a dull belt, turn it on high and press some scrap steel (evenly so you don't gouge it) into the belt and "crumble off" the top layer of dull grit to expose new fresh grit.

It pays to experiment with different belts to save money in the long run.
t
 
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