Grinding Belt Question

A

Arkham Drifter

Joined
Sep 29, 1999
Messages
195
I am buying some belts for the first time and would like to know how aluminum oxide compares to zirconia or ceramic? Many thanks!
 
Just use your aluminum oxides until you run out, then try a couple ceramics. You'd probably get the best overall value with ceramic if you were grinding metal, but aluminum oxides still work well, just need to be replaced much more often. They are inexpensive too, and work well for wood. Ceramic or zirconia is often overkill for shaping wood. A good ceramic belt to try is the 977 Regalloy from 3M. They cost about 5-7 dollars per belt though.
 
You guys must grind different than I do. I've used carbo schroeder a/o belts for goin on 8 years and love em. Tried ceramic and they wouldn't grind worth a crap. Gave a couple ceramics to my neighbor and he tried em, same results. I did just get some 36 grit alumina zirconia belts that perfomed well and I might try some more of them in other grits.
 
And you think the 977 are good, try the 967's! The 3-M ceramic belts are the best all around belts bar none.
 
Hey Rob, I hear the 967s work really well at slower speeds and more applied pressure, and the 977s at full throttle. Thoughts?


Patrick R. Nihiser
Knifemaker
 
ok, i was lucky to get a blade and a half with the 50 grit regal. i get three and a half with norton 50 hoggers! are you one that can stay with the belt till every bit of ceramic is gone? i am all ears on how to get more out of my belts, the A/O hermes stiff and super flex work get on handle scualping for me.
 
Thanks to all for the info regarding abrasives.
One more question: How does silica carbide at the 400-600 grit range fair compared to the other abrasives of the same grit count?
 
This thread is interesting to me. Lots of different results on the belts! I used to use Norton Hoggers, tried the 3-m 977's and got almost twice the life out of them. I do not yet have variable speed, I gring wide open on 2 Wilton Square wheels, but a Frink grinder is at the top of my list. Woner why all the different results? Ideas?
 
Rob and others,

My story is similar to yours. I used to use Norton hoggers, but got almost twice the life from the 977's. Since I grind slowly (usually between 1500 and 3600 SFM) I have found the 967's to last longer/cut better.
I suspect the variation is due to differences in grinding, such as flat vs. hollow, tapered vs. flat vs. stick tang, steel type, and finish of the steel (PG, HR, etc.). Any thoughts?
The majority of my knives are flat ground with tapered tangs, using D2 and ATS primarily.

Brett
 
Interesting question Rob...

My thoughts are belt speed and applied preasure of the work to belt. The harder abrasive probably needing lots of both to keep grains of abrasive fractured so they stay sharp and keep cutting?

If belts could only talk!
 
I just started using the 967's at low speed with the S30V and they are the ONLY belt that worked. The steel ate my 977's (5 tapered tangs with one belt). I hollow ground those same 5 blades at low speed with the 967 and had plenty of belt left when I was done. I just bought some more.

The key in my mind is to use 36 grit. It takes off steel fast, is MUCH easier on the arms, is easier to control, and they will do a whole lot of blades compared to finer grits. After the 36, I go to a 60 or 80 depending on the steel to even everything out and get ready for sanding. The only thing I use finer grits on, are narrow swedges with a smaller wheel (2-3"). In that case I'll use a 60 or even a 120 when it's VERY narrow. Otherwise 36 grit rules! Well, IMHO it does anyway. :)
 
This is interesting. I sure would like to know why me and my neighbor Russ had such bad results with the ceramic belts.
 
Michael, there may be a perception issue. I initially had the same experience. There seem to be two wear levels on ceramic belts. They will pretty quickly wear down to a cutting efficiency that's about half of what they started with. That may be where you think they are used up. After that however, they will grind and grind and grind until there is no grit left on the cloth. I think Geno Denning told me he gets way over 20 blades out of a 977. You might be tossing out useable belts. That's another good reason to start with 36 grit. After that initial wear period, it will continue cutting about like a fresh 50 or 60.
 
L-6 and others that have bad experiance with the ceramics.

By there very nature, the ceramic belts were formulated to fracture to continually make new shapr abrasive particles to keep them cutting. The one thing I am very carefull about is break in on the belts. I never dive right into a flat grind with a new belt. It will wipe off the abrasive from the sharp edge of the blade peeling the abrasive off. I always edge mark my blades, then chisel gring to the scribed lines with an old belt. I go easy on the belts while they are cutting good, and increase pressure as the belt wears.
 
jerry's conment about percived life and stages is true. with me the 3m cuts sharper at first but doesnt last as long as norton beteew the 50 grit ceramics. i will have to try these new 36 ers in 3m, overhead on grinding belts sure grinds away the profit :D
 
I spent some time last night wondering why Rob's and my observations, while similar, were not the same. Part of that is due to the fact that Rob is much more studied and scientific in his approach to things, while I'm completely a seat of the pants type.

It then struck me that I do hollow grinds exclusively, while Rob does mostly flat grinds. The platen and the contact wheel are very different kinds of surfaces, and Rob made some very good points that I will be using from now on when I taper tangs. I have never flat ground a blade - well not successfully anyway, so the problems there are a mystery to me. My schtick is hollow grinding and I do a whole lot of that. A batch of blades I may send to Paul Bos is as much as 200-300 blade inches (not including tangs), so I'm doing it as efficiently as I know how.

My mentioning this is to caution you to listen most closely to Rob if you're flat grinding or working tangs. My remarks may only apply to hollow grinds.
 
There are so many different factors that go into how long a belt will last that a "one size fits all" approach falls under the "That dog won't hunt" catagory.
I personally have tried just about every belt out there over the past 15+ years, and can tell you that Steel type, grind type, grinder type, belt speed, forged or stock removal, and individual skill will all play a part in how long a belt lasts, or doesn't last.
I personally use a 50 grit blue zirconia for my heavy belts, and can get 2-3 times the life from them on forged blades (forge scale and the likes) versus ceramics or Hoggers. Knowing what will work in your shop will only come through trial and error. All the mid grade belts I use (120-400 grit) are standard LS309 AO (j-flex, aluminum oxide). The only place I get picky is on belts finer than 400 grit. I personally don't care for micron belts, the expense versus the life are just not economical (for me). Lately I have tried, and am impressed by, the Norton, Norax 600 grit belts. Everything after a 600 is usually hand work in my shop, but past the 600 grit mark the variety of products is limited anyway. I suppose one could say that this is like most other aspects of knifemaking, use whatever works best for you. Many times the compainies I order belts from will send me samples of new belts to try, and usually after 2-3 belts of a specific type you will know whether or not they are working for you.
 
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