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

M

matto6

Joined
Jan 30, 2017
Messages
237
I'm not getting the life I would hope for out of my ceramic belts when grinding bevels, and could use advice. I'm already doing all the things I've read about

1. Use lots of pressure to fracture the ceramic
2. Don't hit a fresh belt with 90 degree edges
3. Periodically press a piece of hardened steel (an old file) to attempt to re-fracture.

The new belts cut amazing for just a few minutes then the sparks reduce and the heat starts building up faster. So I press harder which just generated heat faster and burns my thumb and risks ruining the temper.

Here are pictures of two belts
1. A Red VSM 50 grit belt that was used to profile 2 small, thin paring knives in Magnacut hardened to around 64 HRC.
2. A Purple Bora-7 36 grit belt that was used to profile 2 small-ish knives in 10V at 65 HRC.

[Side note: Pics in amazon album because this site doesn't allow attaching photos. Are you serious?]

Both were cutting terribly at the end, and when I switched to a new lower grit belt it cut far faster in both cases.

They appear to have a ton of ceramic left in them. I've pressed a file into them pretty hard, and it throws tons of sparks... But they still suck for grinding bevels. Do I just need a harder, sharper object to fracture the ceramic?

EDIT: And I know Magnacut and 10V are abrasion-resistant steels that are hard on belts. I wouldn't be upset if they wore out the belt, but that doesn't seem to be happening here.
 
Have you played with belt speeds?

I agree with you that it seems like my ceramic belts don't last as long as I want.

I noticed if I forget to speed them up I seem to glaze them over.

I think I am not pushing hard enough. I free hand grind. I need to find ones that fracture easier with lighter pressure.
I bet people who use fixtures see things differently as they are probably more forceful.
 
A water mister or flood coolant with help with applying more pressure without building up as much heat. Playing with speeds can definitely help, some belts do better faster and others I get better results with a slower belt speed and more pressure. Some of it also just depends on how thin you are grinding, if you only go to 20 thou before sharpening you’ll get better life and notice less heat than if you are going to 5 thou where it heats up really quickly. Anytime I can use a water mister on the grinder I get better belt life and results. Assuming the belt can run wet.
 
Joshua Fisher said:
A water mister or flood coolant with help with applying more pressure without building up as much heat. Playing with speeds can definitely help, some belts do better faster and others I get better results with a slower belt speed and more pressure. Some of it also just depends on how thin you are grinding, if you only go to 20 thou before sharpening you’ll get better life and notice less heat than if you are going to 5 thou where it heats up really quickly. Anytime I can use a water mister on the grinder I get better belt life and results. Assuming the belt can run wet.
Click to expand...
I'm running 80-90% speed on my 2HP 110v motor. I could try slowing it down.

Water helps preserve the belt itself by cooling it? Or it just allows you to press harder so you end up fracturing the belt better?

I'm curious if you're able to see the pics in the album above and have thoughts?
 
AVigil said:
Have you tried VSM 885? The are for medium pressure
Click to expand...
The pictured red belt is an 885 60 grit, actually. Did I use too much pressure instead of not enough?????

They look like they have a ton of life left but they cut like garbage.
 
Last edited:
matto6 said:
I'm running 80-90% speed on my 2HP 110v motor. I could try slowing it down.

Water helps preserve the belt itself by cooling it? Or it just allows you to press harder so you end up fracturing the belt better?

I'm curious if you're able to see the pics in the album above and have thoughts?
Click to expand...
I looked at the pictures, they looks the same as when I run belts dry and after a couple blades they loose that initial bite that helps them cut really well and cooler. I make mostly culinary knives so really thin geometry, the belt heating up (running on a flat platen versus a contact wheel) can effect abrasive life but the main reason I use water is to keep the blade cool and allow me to apply more pressure or consistent pressure even when the initial sharp grit from the belt wears off.
 
You can flip the belt and get more life out of it. The grain fractures in a certain direction and when you run it in the opposite direction it will cut sharper.

You can also dress the belt with a spur type wheel dresser and freshen the belt a couple of times. It works best when you press it against a hard platen.

Hoss
 
DevinT said:
You can flip the belt and get more life out of it. The grain fractures in a certain direction and when you run it in the opposite direction it will cut sharper.

You can also dress the belt with a spur type wheel dresser and freshen the belt a couple of times. It works best when you press it against a hard platen.

Hoss
Click to expand...
Nice, thanks.

Can anyone suggest a particular "spur type wheel dresser"? I'm not familiar with them, and finding all sorts of google hits.
 
matto6 said:
I'm not getting the life I would hope for out of my ceramic belts when grinding bevels, and could use advice. I'm already doing all the things I've read about

1. Use lots of pressure to fracture the ceramic
2. Don't hit a fresh belt with 90 degree edges
3. Periodically press a piece of hardened steel (an old file) to attempt to re-fracture.

The new belts cut amazing for just a few minutes then the sparks reduce and the heat starts building up faster. So I press harder which just generated heat faster and burns my thumb and risks ruining the temper.

Here are pictures of two belts
1. A Red VSM 50 grit belt that was used to profile 2 small, thin paring knives in Magnacut hardened to around 64 HRC.
2. A Purple Bora-7 36 grit belt that was used to profile 2 small-ish knives in 10V at 65 HRC.

[Side note: Pics in amazon album because this site doesn't allow attaching photos. Are you serious?]

Both were cutting terribly at the end, and when I switched to a new lower grit belt it cut far faster in both cases.

They appear to have a ton of ceramic left in them. I've pressed a file into them pretty hard, and it throws tons of sparks... But they still suck for grinding bevels. Do I just need a harder, sharper object to fracture the ceramic?

EDIT: And I know Magnacut and 10V are abrasion-resistant steels that are hard on belts. I wouldn't be upset if they wore out the belt, but that doesn't seem to be happening here.
Click to expand...

I'm running 80-90% speed on my 2HP 110v motor .....................
How much is that in Feet Per Minute , FPM ? 80-90% speed on 2HP 110v motor don t tell us that data ?

I don't really understand ................ Do you first profiled knives and then grinded bevels with that same belt ? If that's what you do....... Since the surface of the steel you are grinding is small grain in belt will fracture fast .And when they fracture they are not anymore 36 grits , belt become .......40...60.......80 grit .
Use lots of pressure to fracture the ceramic................. It is difficult to define what it is *lot of pressure * for you and what is *lot of pressure for me* . Do you grind free hand or you use some kind of Jig ? Too little pressure and you glaze the belt, too much pressure and you fracture grain too fast .......... For profiling, use old belt , never a new one. The belt with which you grind bevels use exclusively for that , for nothing else .
Can we see picture of knives ? I want to see finish you get after grinding ?
 
matto6 said:
Nice, thanks.

Can anyone suggest a particular "spur type wheel dresser"? I'm not familiar with them, and finding all sorts of google hits.
Click to expand...
You don t need that ......................... It is *Wheel dresser* not belt dresser .
 
Natlek said:
Do you first profiled knives and then grinded bevels with that same belt ?
Click to expand...
No, I started the bevels brand new belts.
I'm doing to bevels after heat treat because they're relative thin kitchen-type knives.

Natlek said:
Can we see picture of knives ? I want to see finish you get after grinding ?
Click to expand...

Yes, I posted a link to an album of pictures in the first post. (This place won't let you post pictures any more... sigh)

Can you tell from those pictures whether they are (a) glazed or (b) fractured too fast? I'm assuming glazed because there seems to be a lot of material left... (?)
 
Joshua Fisher said:
A water mister or flood coolant with help with applying more pressure without building up as much heat. Playing with speeds can definitely help, some belts do better faster and others I get better results with a slower belt speed and more pressure. Some of it also just depends on how thin you are grinding, if you only go to 20 thou before sharpening you’ll get better life and notice less heat than if you are going to 5 thou where it heats up really quickly. Anytime I can use a water mister on the grinder I get better belt life and results. Assuming the belt can run wet.
Click to expand...
Joshua , more temperature and faster is generated on steel if you don t put enough pressure .It's hard to talk about things like this , everyone has their own way . But that's my experience , the way I grind .....
 
matto6 said:
No, I started the bevels brand new belts.
I'm doing to bevels after heat treat because they're relative thin kitchen-type knives.



Yes, I posted a link to an album of pictures in the first post. (This place won't let you post pictures any more... sigh)

Can you tell from those pictures whether they are (a) glazed or (b) fractured too fast? I'm assuming glazed because there seems to be a lot of material left... (?)
Click to expand...
I want to see finish you get on bevels , not belts . it's hard to judge from the pictures. If you can see shiny spots on belt, it's glazed .
 
Natlek said:
I want to see finish you get on bevels , not belts . it's hard to judge from the pictures. If you can see shiny spots on belt, it's glazed .
Click to expand...
Ah sorry. I already moved up to fresh higher grit belts so looking at the knife is useless now... But next time I can share pics.

They definitely started to look more shiny and polished than scratched.
 
matto6 said:
Can you tell from those pictures whether they are (a) glazed or (b) fractured too fast? I'm assuming glazed because there seems to be a lot of material left... (?)
Click to expand...
Belt can be *glazed* only if you don t use enough pressure , If grits simple are rubing in steel ,they create very high heat and that small amount of very small chips which are heated/melted/ more weld to grain ..
 
Last edited:
matto6 said:
Ah sorry. I already moved up to fresh higher grit belts so looking at the knife is useless now... But next time I can share pics.

They definitely started to look more shiny and polished than scratched.
Click to expand...
Do you grind free hand ?
 
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