3M 977 and Soapwater

A

AlaskanHunter

Joined
Nov 23, 2013
Messages
306
This evening I was post HT grinding on a few 1084 blades with a 3M Cubitron 977F belt in 120. The belt was pretty much at the end of its life, or so I thought. I was just about to change it when I decided on a whim to use the spray bottle of dish detergent and water on the belt, sort of a "damp" grinding. Lo and behold, it revived that belt back from the brink of death! It seemed to grind as good as a belt with 3/4ths of its life left in it. I finished my 120 grit grind on two 4" hunters with that method, and it seems to be at half life- about where it gets relegated to pre-HT work.
Can someone explain what is going on here? Ive tried the damp grinding method with just water before, and seen negligible difference. The soap water also seemed to keep the blade cooler as I ground than dipping the blade or spraying water on the belt does. Is it the soap reducing friction, thereby reducing heat? Is it extending life of the belt by helping carry away swarf that would otherwise end up embedded in the surface of the belt (similar to using an oilstone dry vs. with oil)?
I know the usual knifemaker mantra is to "use belts like their free", so I'm wondering if I'm wasting my time with this. After seeing the results tonight, I think not. What do ya'll think?
 
Dish soap is a surfactant, it reduces surface tension of water. So the reason behind adding a bit to your roundup, or spraying a beehive, is probably benefiting you for that reason. Water alone as a coolant or lubricant is rather poor, because it can be thrown off easily. The addition of dish soap helps it both stick to the belt as well as add some lubricity. It also likely helped remove some belt loading of swarf when it "revived" the belt for you. It freed up that loaded swarf so that when it came into contact with your knife it broke free and was released rather than retained.

Soapy water clings to the belt better
Soapy water has greater lubricity than water alone
As water vaporizes, soap clings to the belt and continues to provide some lubricity until it's vaporized.

It would not take much soap to get these benefits over water alone.
 
Well now, I currently have about 4-5 of those same belts at that same stage. I'll have to try this. Thanks!
 
I would guess the dish soap did exactly what it would do to a soaking casserole dish--loosen up all the crap so the water can wash it away. It's like washing that casserole dish with just water vs soapy water. You cleaned all the crap out of the little valleys in the belt, turning it from smooth to rough again.
 
If you guys are already wet grinding or partial wet grinding with something like Trimsol, koolmist, or other metal working fluid I don't think dish soap is going to get you anything as the machining coolants have the same surfactant properties with different chemicals and are optimized to do this job. And have anti foam additives. Dish soap is really a "better than water only" solution.
 
kuraki said:
If you guys are already wet grinding or partial wet grinding with something like Trimsol, koolmist, or other metal working fluid I don't think dish soap is going to get you anything as the machining coolants have the same surfactant properties with different chemicals and are optimized to do this job. And have anti foam additives. Dish soap is really a "better than water only" solution.
Click to expand...
Well, this spur of the moment experiment has opened my eyes to the world of wet grinding, and now I want more. It made keeping the knife cool much easier, and that alone makes it worth it. Does an honest-to-goodness wet grinding set up increase belt life? Do any of you wet grind pre-HT? What benefits does it have there if any? From what I've seen on the forum, the needle valve and sponge set up seems to be the simplest setup. Are there any other systems to consider?
 
AlaskanHunter said:
Well, this spur of the moment experiment has opened my eyes to the world of wet grinding, and now I want more. It made keeping the knife cool much easier, and that alone makes it worth it. Does an honest-to-goodness wet grinding set up increase belt life? Yes. Do any of you wet grind pre-HT? Not worth the mess to me personally What benefits does it have there if any? Cooler cuts at higher removal rates and increased belt life per cu in of material removedFrom what I've seen on the forum, the needle valve and sponge set up seems to be the simplest setup. Are there any other systems to consider? Misters, drippers, just get the fluid onto the belt nearest the work you can
Click to expand...


Everything's better wet in machining, and even though we're abrading, it's really machining. Lubricity helps tool life. Cooling helps tool life. The cooler and more lubricated the cutting operation, the higher the rate of removal achievable.

Except then there's prune hands.

I don't bother with it before heat treat but post heat treat it's wonderful.
 
Sometimes it seems that you can get so much "life" out of some of these ceramic belt when they get to their "kinda worn down" stage that the degradation of backing is going to become a problem before you ever totally wear out the abrasives.
 
jdm61 said:
Sometimes it seems that you can get so much "life" out of some of these ceramic belt when they get to their "kinda worn down" stage that the degradation of backing is going to become a problem before you ever totally wear out the abrasives.
Click to expand...
3M's? I didn't think that was possible on their X weight belts?!
 
I do every stage of my grinding wet (even my handles, but they're stabilized wood). I have a koolmist that runs off a relatively small compressor. I do think it increases belt life, but for me the main advantage is that I never have to dip the blade. Because I mostly make thin kitchen knives, grinding was hellish when I was doing it dry. I also love grinding my handles wet, because it really keeps the dust down. You do get covered in goo, though...

In Japan, wet grinding on rotating stone wheels is the norm.
 
Isn't it harder to see what's going on with the opaque slurry all over the place? That was my experience when wet hand-sanding. It was useful sometimes, but it made finishing work slower because of the mess, so no net advantage except in some corner cases.
 
daizee said:
Isn't it harder to see what's going on with the opaque slurry all over the place? That was my experience when wet hand-sanding. It was useful sometimes, but it made finishing work slower because of the mess, so no net advantage except in some corner cases.
Click to expand...

I mostly do octagonal handles, so that might be why it hasn't bothered me so much. But yes, visibility is definitely reduced. I usually only take the handles to 120# (sometimes 240#)on the grinder and hand sand dry from there. Doesn't take too long.


Sent from my iPhone using Tapatalk
 
Thanks for this. I think I will get more involved in more water. So far it has been a better thing. A friend set up a drip system like I've seen used by rock grinders.
Frank
 
Gee, that's only about TWENTY TIMES cheaper than I what I spent on my koolmist :eek:
Kicking myself...

Does it hold up well?
 
The 3M rep came out to our shop (where I work) today, he is the Industrial Customer Specialist for our area.
We started talking knives and belts and so I showed him this thread.
He was quite surprised about the OP mentioning the soap water benefit.

In simple terms he said- if the rock is down in size, nothing is going to bring it back up.

anyway I wet grind as much as possible. Any costs to me are outweighed by the benefit.
It's a huge timesaver. I try to do alot of the initial bevel on my Kalamazoo 4x36 in a horizontal fashion, belt moving away from me
This is the best setup for wet grinding for me

Now If I could just get a 2x72 grinder manufacturer to make a wet grinding machine.

I even thought about buying a Burr-King wet belt grinder
 
HSC /// said:
The 3M rep came out to our shop (where I work) today, he is the Industrial Customer Specialist for our area.
We started talking knives and belts and so I showed him this thread.
He was quite surprised about the OP mentioning the soap water benefit.

In simple terms he said- if the rock is down in size, nothing is going to bring it back up.

anyway I wet grind as much as possible. Any costs to me are outweighed by the benefit.
It's a huge timesaver. I try to do alot of the initial bevel on my Kalamazoo 4x36 in a horizontal fashion, belt moving away from me
This is the best setup for wet grinding for me

Now If I could just get a 2x72 grinder manufacturer to make a wet grinding machine.

I even thought about buying a Burr-King wet belt grinder
Click to expand...
HSC///: I believe Kuraki explained what was going on with my belt very well. This belt was the first belt used post HT for 1084. The blades have a bit of baked on oil with the usual scale and decarb. I am quite certain that it was a case of gummy swarf clogging a belt, causing it to cut poorly. I think that the soapwater loosened the swarf, exposing the still sharp ceramic abrasive beneath it. Kinda like using a metal hacksaw blade on softwood. It cuts poorly because its teeth are plugged up with sawdust, not because the softwood dulled the blade.
Also, the consensus seems to be that wet grinding cuts better, but water alone does not "stick" to the belt well enough to be of much help. Maybe I'm totally wrong, but this answer seems to make the most sense.

kuraki said:
Dish soap is a surfactant, it reduces surface tension of water. So the reason behind adding a bit to your roundup, or spraying a beehive, is probably benefiting you for that reason. Water alone as a coolant or lubricant is rather poor, because it can be thrown off easily. The addition of dish soap helps it both stick to the belt as well as add some lubricity. It also likely helped remove some belt loading of swarf when it "revived" the belt for you. It freed up that loaded swarf so that when it came into contact with your knife it broke free and was released rather than retained.

Soapy water clings to the belt better
Soapy water has greater lubricity than water alone
As water vaporizes, soap clings to the belt and continues to provide some lubricity until it's vaporized.

It would not take much soap to get these benefits over water alone.
Click to expand...
 
You must log in or register to reply here.
Back
Top