Help me liven up my ceramic belts - or declare them dead

HSC /// said:
Also I have found a surface grinder or attachment more efficient and faster at grinding. So I can surface grind in the distal taper and start off the bevels with the surface grinder attachment. You can get more grinding out of the belts this way in my experience.

This generates a lot more heat so it has to be water cooled.
Click to expand...
Yeah I had no problem doing a distal taper on them, even using an old belt. Unfortunately my SGA doesn't tilt to do bevels.

You mentioned grinding at lower speeds.. Your regular approach is to grind low-speed with high pressure?
 
matto6 said:
Yeah I had no problem doing a distal taper on them, even using an old belt. Unfortunately my SGA doesn't tilt to do bevels.

You mentioned grinding at lower speeds.. Your regular approach is to grind low-speed with high pressure?
Click to expand...
I grind freehand, no tool rest, so whatever pressure that is by hand/arm strength.
 
I’m a relatively new knife maker 1 year 4 ish months but a few things I’ve noticed.

If the belt isn’t cutting how you expect or you’re heating up your blade hot enough to dip in water in one pass you need a fresh belt.

I don’t refracture I’ve tried it with a diamond dresser and while it improves cutting ability it only last a few min before it’s even worse than it was before refracture.

I’ve done some 10V at 65hrc and it took one belt perside but the belt wasn’t shot it just wasn’t good for 10V anymore it was still okay when grinding AEB-L or pre heat treat grinding.

What I do is this I’ll use fresh ceramic belts whenever grinding becomes an issue. The semi worn belts will go towards less wear resistant steel, profiling, pre heat treat grinding. I’ll also take worn ceramic belts and use then them for handle shaping and contouring before switching to jflex belts. When they no longer cut handle material efficiently they might be used for kydex for a while then they’re declared dead.

Using this method allows me to keep the number of belts and abrasive types at a minimum.
 
I also grind slower then most, 30-40 on the VFD, that and free hand grinding is probaly why I find belts meant for medium to low pressure work best for me.
 
Thescrawnylumberjack said:
If the belt isn’t cutting how you expect or you’re heating up your blade hot enough to dip in water in one pass you need a fresh belt.

What I do is this I’ll use fresh ceramic belts whenever grinding becomes an issue. The semi worn belts will go towards less wear resistant steel, profiling, pre heat treat grinding. I’ll also take worn ceramic belts and use then them for handle shaping and contouring before switching to jflex belts.
Click to expand...
Thanks, makes sense. But don't you end up with a huge stockpile of half worn belts that way? Or do you do enough other types of steel that it's not an issue?

Seedy Lot said:
I also grind slower then most, 30-40 on the VFD, that and free hand grinding is probaly why I find belts meant for medium to low pressure work best for me.
Click to expand...

Thanks. Which low-to-medium ceramics are your goto?
 
matto6 said:
Thanks, makes sense. But don't you end up with a huge stockpile of half worn belts that way? Or do you do enough other types of steel that it's not an issue?



Thanks. Which low-to-medium ceramics are your goto?
Click to expand...

I have a decent pile of belts that are more like 3/4 worn but that just means if the pile is to much I ditch the most worn ones instead of having 3 different grits of zirconium that die in 3-5 handles or some times less. A 36 grit, 60 grit, and 120 grit ceramic belt can last dozens of handles even when worn.

I grind a decent amount of AEB-L and A2 which grinds like butter compared to magnacut and 10V so the AEB-L and A2 do a good job of consuming the half used belts. Half used belts are also very good at pre heat treat grinding. Removes material slower from soft steel so it gives a level of control to not mess up the grind as easily.
 
I saw the pics and wanted to say that you didn't use enough pressure.

But then, those steels do eat belts. The only person who comes away with high resistant steels and worn belts is N Natlek .

His 40 grit belts make 320 grit finish. He uses warp speed, hollow grinds, high pressure, jigs and black magic to achieve this.

Jokes aside, those belts do still have life left in them, but if it doesn't fit your grind style and equipment use them for less wear resistant steels and profiling tasks.
 
Haha thanks Fredy.

Also - I just noticed that Red Label Abrasives blog recommends a grease stick
"If you work mainly with metal, you can do this by applying an abrasive belt grease stick before using the belt, which can reduce both the friction heat and the risk of clogging."

Has anyone seen success with this? Seems to align with Josh's idea that a mister keeping everything cool allows more pressure and longer belt life.
 
Just as a side note on abrasives one grit belt does not break down and become another grit, a 36 grit belt will never become a 120 grit belt. The grit numbers are how many grains of abrasive are in 1 square inch of backing material as they break down they do not multiple they just leave a less aggressive finish and the tops of the grains become more uniform, think of it like a mountain range the taller mountains or grains would come into contact first. This is the initial “bite” that makes a belt feel like it’s really cutting, once the peaks break down and you hit more of the grains it feels less aggressive and leaves a finish that appears smoother but is still a 36 grit finish, as they wear down even more they become less effective and start burnishing the surface as the grains get rounded out making it feel even less aggressive and leaving what seems to be a even smoother finish but it is still just a 36 grit finish that’s been burnished by dull grain. N Natlek is right that higher speed and pressure cuts surprisingly cooler as you get less rounding or glazing of the grain and a ceramic belt lasts surprisingly long that way, usually that means grinding with a jig on a contact wheel and depending on how thin you are grinding and if the belt has any cooling top layer added or not possibly a flood or mist system. For freehand grinding you’ll likely have to accept that you won’t get 100% life from a belt grinding bevels, I prefer bevel grinding with fresher belts as it’s faster for freehand grinding since I’m likely not getting optimal breakdown of the abrasive, at the point the belts start taking longer or less effective I switch them to profiling belts or scrap belts for odd work. I never have to buy belts to profile blanks as I have a steady supply that multiplies faster than I can use. You can often profile 50-100 blades off one “worn” belt. Play with speeds and find what works best for you as everyone has a different grinding style.
 
matto6 said:
Haha thanks Fredy.

Also - I just noticed that Red Label Abrasives blog recommends a grease stick
"If you work mainly with metal, you can do this by applying an abrasive belt grease stick before using the belt, which can reduce both the friction heat and the risk of clogging."

Has anyone seen success with this? Seems to align with Josh's idea that a mister keeping everything cool allows more pressure and longer belt life.
Click to expand...
I’ve tried grease sticks and not found they helped much other than making a mess but some people like them. A mister while it does make a mess is the most effective way to cool the work while grinding, outside of how you use the abrasive.
 
I just picked up some 50 grit VSM 885 from Trugrit for $7 ea.

I do 90% of the grind with a 50 grit belt, I get several small blades from one belt, but even if I just got one blade $7 one of the less expensive things that go into a knife.

Once I think while grinding "This is not cutting as well as it should" experience has taught me to stop with that belt and grab a new one. This not only improves your grind but decreases time wasted using a dull belt.
 
Josh is partly correct. Normally, belts get coarser as they wear down like mountain tops. But the wider tops on the grains have rounded edges so it doesn't cut as fast or leave as deep a scratch.
Cubic structure belts, like Cubitron, have square grains in a cubic crystal form. The cleavage plains are parallel to the flat surfaces. As they wear, they shear off along the cleavage planes and leave new sharp edges on the top of the square. They don't change appreciably in grit size. The new grains don't wear down as much as they glaze over. When you refresh it you get newly sheared grains. This can be done as many as five or six times. I use a 3" coarse bar type diamond wheel dress from HF.
I have not used the slower speed belts, but the regular ones need FAST speed and lots of pressure. You press HARD as you draw the blade fairly quickly across the belt. Moving the steel too slow causes the metal swarf to fuse on the grains and glazes them. It is not uncommon for the blade to glow red when hogging. A mist system helps with lubrication and heat control.
 
Joshua Fisher said:
Just as a side note on abrasives one grit belt does not break down and become another grit, a 36 grit belt will never become a 120 grit belt. The grit numbers are how many grains of abrasive are in 1 square inch of backing material as they break down they do not multiple they just leave a less aggressive finish and the tops of the grains become more uniform, think of it like a mountain range the taller mountains or grains would come into contact first. This is the initial “bite” that makes a belt feel like it’s really cutting, once the peaks break down and you hit more of the grains it feels less aggressive and leaves a finish that appears smoother but is still a 36 grit finish, as they wear down even more they become less effective and start burnishing the surface as the grains get rounded out making it feel even less aggressive and leaving what seems to be a even smoother finish but it is still just a 36 grit finish that’s been burnished by dull grain. N Natlek is right that higher speed and pressure cuts surprisingly cooler as you get less rounding or glazing of the grain and a ceramic belt lasts surprisingly long that way, usually that means grinding with a jig on a contact wheel and depending on how thin you are grinding and if the belt has any cooling top layer added or not possibly a flood or mist system. For freehand grinding you’ll likely have to accept that you won’t get 100% life from a belt grinding bevels, I prefer bevel grinding with fresher belts as it’s faster for freehand grinding since I’m likely not getting optimal breakdown of the abrasive, at the point the belts start taking longer or less effective I switch them to profiling belts or scrap belts for odd work. I never have to buy belts to profile blanks as I have a steady supply that multiplies faster than I can use. You can often profile 50-100 blades off one “worn” belt. Play with speeds and find what works best for you as everyone has a different grinding style.
Click to expand...
Yes but it will grind steel with finish like 120 grit belt .I never said that they multiple .I said they leave finish like it was 100-200-300 grit . ........Reason that they cut so well for me on high speed is exactly that ...number of particle on square inch . Once I said on this forum that I which they make belt with 80 grit size grains but in number of 36 belt on square inch . .Look Joshua I know lot for this belts, I even started several topic about them here .I agree with most of what you say . Maybe it is my English factor that I don t elaborate to deep in this ..........
Lot of factor determine how and how long belt will last . I use Klingspor CS910Y belts
* Y-Weight is a heavy duty backing with the most strength to withstand the pressure of heavy sanding and product removal *
Speed and pressure are most important . I have no idea how fast or often grain fracture .I never do that or tried on purpose to fracture grains .But they fracture obviously and I get 240 grit finish with what was once 40 grit belt :) What change is that instead of three-four heavy pass I make two or three pass /depend on steel / and need to cool blade . I only watch out NOT to glaze belt ..... Of course that they not cut fast steel as like new 40 grit belt .But on speed and pressure I grind they remove lot of steel.
And they last long long time to me , regardless which steel I grind or how thin it is .

One more thing ..... for a good even finish regardless of the grit in question, it is very important to pull steel evenly .Think on surface grinding attachment ...............
 
Last edited:
Stacy E. Apelt - Bladesmith said:
Josh is partly correct. Normally, belts get coarser as they wear down like mountain tops. But the wider tops on the grains have rounded edges so it doesn't cut as fast or leave as deep a scratch.
Cubic structure belts, like Cubitron, have square grains in a cubic crystal form. The cleavage plains are parallel to the flat surfaces. As they wear, they shear off along the cleavage planes and leave new sharp edges on the top of the square. They don't change appreciably in grit size. The new grains don't wear down as much as they glaze over. When you refresh it you get newly sheared grains. This can be done as many as five or six times. I use a 3" coarse bar type diamond wheel dress from HF.
I have not used the slower speed belts, but the regular ones need FAST speed and lots of pressure. You press HARD as you draw the blade fairly quickly across the belt. Moving the steel too slow causes the metal swarf to fuse on the grains and glazes them. It is not uncommon for the blade to glow red when hogging. A mist system helps with lubrication and heat control.
Click to expand...
I believe that ceramic grain are designed to fracture when tip get dull and make more resistance when cut steel .

Ceramic grains feature very small fracture planes which allow each granule to constantly resharpen and provide extremely consistent stock removal through its usable life.

Microcrystalline​



The term "microcrystalline" describes a special structure found in the grit of an abrasive. Each individual ceramic abrasive grain in this structure is formed from a large number of smaller aluminium oxide particles during the manufacturing process. As the fine boundaries between the individual aluminium oxide particles remain intact inside the ceramic grain, the grain is given a so-called microcrystalline structure.
Abrasives with grains that have a microcrystalline structure possess self-sharpening properties: as soon as the point of a grain becomes dull during the grinding process, the point is shed from the grain on account of the increasing pressure. Since taking place along the microcrystalline structure, this shedding creates a new sharp-edged grain point that allows the user to keep grinding with no loss in aggressiveness.
The prerequisite for the optimal wear characteristics of an abrasive with ceramic grains is that the user exerts sufficient tool pressure while grinding.
The main field of application for microcrystalline, ceramic grains are hard-to-machine materials such as alloyed steels, stainless steels and so-called superalloys.
Klingspor carries various abrasives with ceramic grains in their product range. The flexibility and tear resistance in the backing used for these products varies with the applications for which they are used. Klingspor's range in this product category also includes vitrified abrasives with a microcrystalline structure and multibond, which are suitable for applications requiring cool grinding.
Click to expand...
 
Last edited:
Stacy E. Apelt - Bladesmith said:
Josh is partly correct. Normally, belts get coarser as they wear down like mountain tops. But the wider tops on the grains have rounded edges so it doesn't cut as fast or leave as deep a scratch.
Cubic structure belts, like Cubitron, have square grains in a cubic crystal form. The cleavage plains are parallel to the flat surfaces. As they wear, they shear off along the cleavage planes and leave new sharp edges on the top of the square. They don't change appreciably in grit size. The new grains don't wear down as much as they glaze over. When you refresh it you get newly sheared grains. This can be done as many as five or six times. I use a 3" coarse bar type diamond wheel dress from HF.
I have not used the slower speed belts, but the regular ones need FAST speed and lots of pressure. You press HARD as you draw the blade fairly quickly across the belt. Moving the steel too slow causes the metal swarf to fuse on the grains and glazes them. It is not uncommon for the blade to glow red when hogging. A mist system helps with lubrication and heat control.
Click to expand...
I think moving the blade is the important thing that some people miss. If you move the blade too slowly, things don't work as well in my experience. There are tons of factors like pressure, belt speed, grit size, grit shape, belt stiffness, backing shape, backing hardness, etc.

I also like N Natlek suggestion of a spaced out coarse grit. I wish structured abrasive belts came in coarser grits, the space between the grit structures really helps.
 
".... the space between the grit structures really helps. ...."

This is where gator belts are champ. An A300X 3M Trizac gator will eat steel. I also find they leave a very smooth surface. They come up to 800grit.
I mainly use them post HT in the A300-A100 range (80grit to 180grit).
 
so i guess my coffee has not kicked in yet !! or i'm just confused here .. i thought (think) to stop using a belt/sandpaper once it stops cutting well
(use it like it is free) it just keeps going up in price!!!! but i have always found once it stops cutting well it does make a lot more heat ,and we enter the realm
of diminishing returns.. so im simply better off the grab a fresh belt and keep going... did i miss something ???
 
Not all belts last the same if there is not enough pressure or speed to break down the structure exposing new cutting edges.

For me I have not been a fan of VSM ceramic belts as I have always felt that I was not getting the life that I should out of a belt. This was with the 885s. I kept buying them because of the price and they worked well enough.

Recently I started using the VSM 880s and they keep cutting for me until the belt is obviously trashed.

Yes I could keep moving to a new 885 belt but makes a lot more sense for me to use the 880 as it lasts noticeably longer for what I ask of it.

Everybody has different grinding styles and expectations and there just happens to be a bunch of different belts to try.
 
Pinoy Knife said:
so i guess my coffee has not kicked in yet !! or i'm just confused here .. i thought (think) to stop using a belt/sandpaper once it stops cutting well
(use it like it is free)
Click to expand...
That's fine - if a belt is truly past it's prime, toss it. I'm trying to figure out whether I'm ruining belts sooner than I should be by using improper technique.
There are many posts that say things like, "Oh man now that I do XYZ my belts grind cooler for much longer". I'm trying to find that sweet spot.
 
You must log in or register to reply here.
Back
Top