Belt Life

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Aug 29, 2019
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Hello, working on knives just about every day for about a year and a half, consider myself very much a beginner/novice. I have a question about belt life. You begin a grind with a new ceramic 40 grit belt and you complete the bevel with a progression of belts. So you now have this once used 40 grit belt. I have read many time about not wasting time and materials using used belts. There may be other uses for this belt but would experienced knife makers not use this belt to start a new grind?

Thanks, Joe
 

Cushing H.

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this has been covered a LOT .... but for yucks, I will add my most recent thinking (I am only about 1.5 years into this also). First of all .... most of the knives I make are longer kitchen knives .... 6 inches or more .... so the thought of really effectively getting more than one knife out of a single belt is .... no longer in my thoughts. From what I have been seeing, it is really about performance - and performance goes DOWN the second a belt touches steel. Second, it has become really apparent to me recently that when doing a full flat grind, it is MUCH easier to create that long blade-width flat with a new sharp belt than an older duller belt. third, sharper (newer) belts definitely do not heat up the metal as quickly.

Putting all that together, today what I do is: use an old 60 grit belt (hopefully only used once) to grind in the 45 bevel as I am starting the grind, and to take it down maybe 1/2" or so down the blade. then I shift to a new belt, and hopefully can then complete the grind for the entire blade with that belt (this allows for really establishing that flat, and hopefully keeping heating down to a minimum). That now-used 60 grit belt now becomes the one I use to establish the 45's for the next blade, etc, etc. I have gotten to the point where I am using that 60 grit belt to take the edge down to 0.005- 0.008 .... BUT am making sure my flat grind is FLAT (or as much as I can make it). THEN I shift to a 120 grit .... and from then on it is really surface finish refinement, NOT actually removing much metal. the 120's thus last a while ... several knives (until either they are not easily removing the 60 grit lines, or the steel is heating too quickly to control). Up from t he 120's come the Gator belts at 100 micron then 60(?) micron. To give an idea of lifetime .... two years ago I bought my first 100 micron gator from pops .... and just last week I put it in the trash. You get the picture ... the 60's are the workhorse and get trashed frequently ... the higher grits last longer and longer.

One final thought - making kitchen knives, my stock is usually 0.7 - 0.9 MAX. I would NOT want to use a grit lower than 60 for the initial grind, as it would take way too much to get out those really deep gouges from, say, 36 grit ... and with that thin stock, there is not a lot of metal to play with .... so I always start at 60.

Also, I recently created a thread about "now I get it ... use belts like they are free" ( https://www.bladeforums.com/threads/use-belts-like-they-are-free-ok-now-i-get-it.1755098/ ) take a look. I stand by that. Dont get me wrong ... they are not free (at least for the hobbyist) .... but the difference between a fresh belt and even a moderately used belt is incredible.
 

FredyCro

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40 ceramic grit belt should have much more life in it then just bevels for one knife.

How much, depends if you grind hardened blades and how you grind (pressure, speed) and what kind of knives and steel you are grinding (5 edcs have probably the same surface as a large kitchen knife, some steels are more abrasion resistant).

You can use a used belt for profiling, initial 45s, heavy removal at start of the grind (especially if you grind before hardening, so extra heat won't matter). Dress your belts if you don't grind with enough pressure to break ceramic to fresh grit.

Try it out and see if it works for you, also try different brands in same grit and compare how they fit your techique.
 
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Thank you for the information. I was probably using one belt for at least 2 maybe 3 knives. I've been having some problems lately in my grinding and realized last night that the belts are just not cutting and maybe I should always use a new belt for grinding. I think I needed some reassurance. Well I have ordered a number of new belts and hope to keep myself well stocked.

Thanks again, Joe
 
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Hello FredyCro,

I have just read about dressing ceramic belts. I have also at times felt that an 80 grit belt cuts faster then a 40 grit belt.

Thanks for the info, Joe
 

JTknives

Blade Heat Treating www.jarodtodd.com
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If your only getting one blade per belt then your buying the wrong belts. My go to was 50grit blaze belts and I would get around 6-10 blades ground with it. Key is to use an old belt to break the corner first so you don’t strip a lot of grit On a fresh belt.
 

Hubert S.

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My experience is similar to Cushing's. Like him, I almost exclusively grind kitchen knives after hardening, mostly AEB-L, and use one 60 grit belt per knife.
 

FredyCro

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Hello FredyCro,

I have just read about dressing ceramic belts. I have also at times felt that an 80 grit belt cuts faster then a 40 grit belt.

Thanks for the info, Joe

If you notice problems put a fresh belt and see if that fixes it. Mostly it does. Keep the used belt for rough work. In my (limited) experience a belt life will be better using a push stick or a jig since you will be able to put more pressure while grinding.
 

john april

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My experience is similar to Cushing's. Like him, I almost exclusively grind kitchen knives after hardening, mostly AEB-L, and use one 60 grit belt per knife.
. what brand of belts are you guys using? i grind hardened blanks as well, i get around 4-8 blades depending on size using one 3m cubitron 984f.
 
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I say don't be scared of the 36-40 grit belts. I just have a basic 2x42 without speed control, just fast. I grind thin kitchen knives at 0.06 inch, hardened steel from JT. They cut so much cooler and seem to hold up well, they are worth it imo. Even in comparison to 60 grits, the difference is huge. I go 36, then 60 just to knock off the scratch pattern, then to hand sanding. I need to get a tizact next, because 60 grit scratches can run deep.
 

FredyCro

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I say don't be scared of the 36-40 grit belts. I just have a basic 2x42 without speed control, just fast. I grind thin kitchen knives at 0.06 inch, hardened steel from JT. They cut so much cooler and seem to hold up well, they are worth it imo. Even in comparison to 60 grits, the difference is huge. I go 36, then 60 just to knock off the scratch pattern, then to hand sanding. I need to get a tizact next, because 60 grit scratches can run deep.

Yeah, especially on a smaller grinder, you really need those heavy belts. I was running 40 VSM ceramic and then went straight to 120 VSM ceramic (couldn't get 60 ceramic, and 60 AO were dying like instantly) and then gator on my 2x42 (50x1020 actually) .
 
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Hello, working on knives just about every day for about a year and a half, consider myself very much a beginner/novice. I have a question about belt life. You begin a grind with a new ceramic 40 grit belt and you complete the bevel with a progression of belts. So you now have this once used 40 grit belt. I have read many time about not wasting time and materials using used belts. There may be other uses for this belt but would experienced knife makers not use this belt to start a new grind?

Thanks, Joe
Ceramic belts don t like soft steel
Speed is your friend
Pressure is your friend
Ceramic belts last much , much longer then one knife ...............
Ceramic belts don t get dull , they change grit size when fracturing

Knife maker that can only do one knife with one belt ....is doing everything wrong !
 

Hubert S.

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. what brand of belts are you guys using? i grind hardened blanks as well, i get around 4-8 blades depending on size using one 3m cubitron 984f.
That's impressive. I've tried different brands and did not see a huge difference in belt life. I used VSM for the last few knives, but I'll give the Cubitrons another try. I suspect it's not the belt, but the operator, though.
 

Cushing H.

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. what brand of belts are you guys using? i grind hardened blanks as well, i get around 4-8 blades depending on size using one 3m cubitron 984f.
John - I am using Blaze belts. To maybe be clearer - I could (and have) gotten more than one large kitchen knife blade per belt, BUT the fresh belt just works so much better that it’s not really worth it to me right now to struggle with a used belt.

also ... I DO dress the belt periodically, and I DO NOT use a fresh belt to break the angle.
 

Cushing H.

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I say don't be scared of the 36-40 grit belts. I just have a basic 2x42 without speed control, just fast. I grind thin kitchen knives at 0.06 inch, hardened steel from JT. They cut so much cooler and seem to hold up well, they are worth it imo. Even in comparison to 60 grits, the difference is huge. I go 36, then 60 just to knock off the scratch pattern, then to hand sanding. I need to get a tizact next, because 60 grit scratches can run deep.
Perhaps ... but I kind of like my fingers more or less the way they are ... :)
 

Hubert S.

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John - I am using Blaze belts. To maybe be clearer - I could (and have) gotten more than one large kitchen knife blade per belt, BUT the fresh belt just works so much better that it’s not really worth it to me right now to struggle with a used belt.

also ... I DO dress the belt periodically, and I DO NOT use a fresh belt to break the angle.
Same here. I remove a good bit of material with a previously used belt, then switch to a new one because I get a much cleaner grind. I could see maybe getting two knives from a belt, but 4-8 as John says is truly impressive.
 

Rick Marchand

Donkey on the Edge
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Ceramic belts don t like soft steel
Speed is your friend
Pressure is your friend
Ceramic belts last much , much longer then one knife ...............
Ceramic belts don t get dull , they change grit size when fracturing

Knife maker that can only do one knife with one belt ....is doing everything wrong !
Of course, you have the option to use a fresh belt every knife but what Natlek says here is worth quoting. I have been doing this for 17 years and only just realized I had been running my ceramic belts(especially low grit) too slowly @3200 SFPM. I adjusted my machine to its max of 4600 SFPM and belts that were completely glazed over, refractured and are cutting well, once more. The refracture 36gt cuts more like an 80gt but it's like a new belt. I feel stupid for not figuring this out until now... apparently, I never bothered to look into it, because every abrasive manufacturer clearly states it in their literature. I cringe at the belts I prematurely threw out over the years.
 
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John - I am using Blaze belts. To maybe be clearer - I could (and have) gotten more than one large kitchen knife blade per belt, BUT the fresh belt just works so much better that it’s not really worth it to me right now to struggle with a used belt.

also ... I DO dress the belt periodically, and I DO NOT use a fresh belt to break the angle.
Where you learn that you need to dress belt periodically ? That was wrong ,belt is not grinding stone with millions grit glued together .........
If you can take good close picture of one belt /after grinding ONE knife/ I m sure that I can tell you what are you doing wrong .......
Common mistake is not enough pressure ,grits are more rubbing then cutting and that mean higher temp. so grinding chips are to small and they burn/melt and they get stacked to top of ceramic ......If you see on belt small shine/glittering dots .........that was not dull ceramic tip, that is from steel you grind welded to tip of ceramic ...And of course that belt will no more cut and will make lot of heat ......
 
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