How many belts does it take?

J

Jkite

Joined
Jan 29, 2013
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I understand that it depends on several factors but, in general, how's many belts do you go through on a typical fixed blade.

On about a 4" blade I think I used like (2-3) 36 grit (3-4) 120 (36 & 120 were norton blaze), (3-4) 220, (2) 400. And then I used some old belts I had laying around.

That seems like a lot of cash just in belts alone for one knife. Or is this just the norm.

Thanks
 
I havent been going at it for that long, but that seems excessive. I have profiled multiple knives out of a single belt, and have profiled 3 Knives on my first 36 grit and its still cutting fine, and bevelled 4 already on a 60 grit zirc, and these were all about 6 inch blades. I see no reason why a ceramic belt, such as a blaze should not be able to last through multiple knives.
 
I start with a Norton Blaze belt in my 2x42 at 60 grit then go to 120. After that I switch to Trizacts in A300, A100 and A45. Sometimes I may be to an A30 even. I get quite a few blades from these belts, so the price per blade is really quite low.

I also grind most of my blades hard.

If you're using 2 to 3 belts for each grit, I'd say something is wrong somewhere! What size stock are you using?
 
Seems a little overkill. I am getting about 4-6 knives out of (1) 36-80-120 norton blaze and several more out of the engineered abrasives (norax,etc.) for finish work. Maybe stretching the useage but i do keep them clean (gum rubber). Any kind of "loading" decreases the life of the belt so i try to minimize thru cleaning and keeping the metal cool. Honestly, i have some 36 grit blaze that i have relegated to hogging that are still in use after 15-20 blades.
 
What size belts? I do a lot of stainless steel grinding on a 6"X48" belt sander, and use 3m cubitron II 36 grit belts for heavy stock removal. I would guess one of these belts would probably grind the equivalent of AT LEAST 50 blades. By far the best, most aggressive, longest lasting belts on the market. The blades I have ground so far, I follow up with a 3m 777f 120 grit belt, which will probably take the 36 grit down to 120 grit on 20-30 blades. So I guess what I am saying is either you must be using a much smaller belt, or need to get much better quality belts. The coated abrasive belts are best. Make sure you are not using belts designed for woodworking.
 
What belt size..? If you're using 2 x 72" belts, you should be able to
get at least one blade per belt per grit....(small-to-medium size blade)..

If not, question your belt speed,and/or technique.
 
Yeah that seems like far too many belts per blade, especially considering you said they are Blaze belts, which are a high end ceramic and should last a whole lot longer than half a knife. It could be possible that you are running them too slow, or not using enough pressure, this can cause the belts to glaze over and seem like they are dull. I would try increasing the belt speed or pressure against the belt when hogging and see if that helps to keep them from glazing. Some ceramics to take a significant amount of pressure to fracture the grain and expose new sharp cutting grit.
 
Great to try and see what works best for what but two things here to concider and those are is the grinding pre or post heat treatement, and Norton ceramic belts do work better as do 3M ceramics under different conditions for each. Nortons require more pressure and or more belt speed. 3M are quite the opposite. Frank
 
Even hardened steel isn't that harsh on ceramics. What's the condition of the belts when you're done? Are they stripped of abrasive or do they still have abrasive left but are dull?

Using one each of the 3m 984 cubitron IIs in 36 and 60 grit and one each of the trizact CFs in and A300, A160, and A45 I can grind 10+ 4" blades before heat treat. The trizact CFs will have enough life to still do the post heat treat finishing.

People grind differently and under different conditions (steel type/hardness/different machines, etc), but A single 36 grit blaze aught to eat up quite a few knives before it's completely worn out.
 
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I forge to near net so I get maybe 20-30 blades per belt before the blazes are whipped.

-Page
 
With my lil 2x42, There would be no knife left before I wore out a single blaze belt. Are you using enough pressure to expose new grit?
I had a norton blaze 80 that I used so long it eventually started to polish lol, but was still cutting decently! Just the grit became progressively finer. It only got scrapped because it wasn't cutting fast enough to be a low grit, but didn't leave a consistently fine enough finish to be a high grit so I laid her to rest.
 
If I read you right, you say you're using about a dozen belts (quality ceramics no less) per 4" blade?

Even on a 1x30, I think this would be excessive. I use a 2x72 that I built, and I'd say I get at least 3 or 4 knives per belt (if not 8 or 10, depending on what I'm using the belt for), as opposed to 3 or 4 belts per knife.

I cut the rough profile on a band saw, and clean up on a 60 or 80 grit. From there I can rough grind with the same, then clean up with a 120 before HT. After that, it's finish grinding with 120 to 220, then maybe a 400.

At any rate, per knife, I might use 3 or 4 different belts (maybe more depending on final finish), but each of those belts can be used for several blades before they are completely worn.
 
Maybe I missed something here, but what type of steel you are working with can make a lot of difference on the number of belts per blade but the quoted amount is way too many even on 3v, D2 or M4, until M4 is tempered and then it is a bear.
 
Two things I know of can greatly reduce the life of even a high quality ceramic roughing belt. One, grinding bevels without first grinding your starter bevel with an old belt. The abrasive can strip right off the belt quite early if you don't do this. Also, save your new belts for bevels and flats. Use old belts for profiling, tang hollowing, etc.
Two, if you are a blade forger, don't grind the scale off your knives with a new belt. Use an old belt, like one of your profiling belts, and a contact wheel to quickly scrub most of the forge scale off of the surface. That scale is really hard and can dull belts quickly.
 
I have not seen belt speed mentioned and have to ask.

Jkite; What belt speed were you using when you ploughed through all those belts on one blade?

And how long were you grinding for?

First thought, from one who admittedly knows very little about grinding but needs to learn, would be that the speed could be way off. I understand (and I could be wrong) that there are optimum speed ranges for different belts and that the ceramics in particular usually need to run fast in order to knock off the tips as they dull and expose fresh cutting edges. Run too slow and they'll just fill the low spots with metal and stop cutting.

I don't know what happens with too fast. I doubt I'll ever have the nerve or the equipment to find out.
 
That sounds like something is really wrong. I use 2X72 belts, ..... and use them like they were free. My friend takes the belts I toss in the "used" bin and says they are still good. I get anywhere from a few to dozens of blades per belt. At the finer grits, it is less, but still not more than one belt for a large blade. I budget $10 total in belts per knife, but it actually is probably less than $3-4.
 
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