black scale(?) forming on my blades when grinding?

bladsmth said:
I sat back for a day to let the others post advise. I believe it is exactly what they are calling "belt gunk".

The grit on the belt is held in place by being encased in a resin layer. At the too high speed of you 2X42, combined with allowing the blade to get much hotter than when hand grinding,plus pressing too hard,..... it melts and burns this resin.
No real damage to the blade, and probably not much to the belt.

To deal with this there are several things to do.
The best option would be to slow down the grinder....since that isn't going to happen...
The next is to not heat up the blade so much. Start with pressing less hard and cooling the blade more frequently by dunking it in water. Try and avoid long continuous grinds. Grind a pass, lift the blade for a few seconds, grind another pass, dunk, etc.
Things like using a different belt type might help, too, but keeping the blade cooler will be the most simple option for your setup.
The black streaks may be more of a problem with some metals than others because some grind more "gummy".

The black stuff will grind/sand off, so don't worry too much about it anyway.




The final solution to your problem is - Start saving up for a GIB or KMG clone kit. IAAP, make it VS.

When someone says they can't afford a tool or product, a good solution is to lease out your shop.....to yourself.
Put a coffee can with a slot in the lid on the wall or near the door. EVERY time you go out to work on a knife, stick $5 in the slot. You have no problem spending $5 on a beverage, or a hamburger, or gas to drive across town to a store,...so why not save a few for your grinder. In much less than a year you can order the new grinder and have the money painlessly. Epoxy on the lid, to avoid the temptation to "Grab a few bucks".If you raid the can every time you want to go out to eat, it will never get full. If $5 is unrealistic, try $1 and save a little longer.

Another good way to save for a tool is to pay for it in coins. The average person can save several hundred dollars a year just by keeping all the coins they get in change every day. Don't spend any coins. Instead, every night, dump the coins from the day into a big jar/bottle/can. Roll them every six months or yearly and put the rolls in a box labeled GRINDER. Just like the previous savings suggestion...don't spend it on anything but the tool you are saving for.
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Thanks again. I figured it was just a matter of slowing down and keeping it cool. Its kind of like a catch-22 with this grinder. If I dont put too much pressure on it it takes forever to flatten the blades. If I put some pressure on it, it gets really hot real quick and poof: black crap. Bottom line is a lot more patience flattening my blades.


My next buy is to get some gator belts which should help. Ive already started working on a 2x72 conversion which will help too. A KMG is on my list, Ive already been saving for one!
 
rwn2000 said:
this is how I pay for my fall "guys only" fishing trip every year. I don't even roll them, just take the 10pound jar into the bank and use their automatic sorter/counter. no hassle with SWMBO either. :)
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Whats SWMBO stand for? I assume its several kind words to describe the wife?
 
I love it. Rumpole fans even here.

I have a lot of the DVD's if anyone is interested.
 
I get the same on my blades when I push too hard on the blades. Stacy nailed it in his earlier post - it's the resin from the belt.
 
FYI, most banks won't take rolled up coins anymore. Last couple times I tried, they made me unroll them and they poured them into their auto coin counter thingie.
 
I wear the pants, too, but she picks them out for me :D

My bank won't take more than a pocketful of change at a time :mad: Last year I had to go around to places that charge 9% to dump your coins in their machine. That takes a while and adds up to $$$ when you're talking about a 5-gallon water jug full of coins :eek:
 
You won't believe this but...

I tried again tonight to get it off. This time with a 120grit belt with less pressure and frequent water dips. It came right off except for one blade.

So just for kicks I decided to do some hand sanding. It came right off with some 120 grit SC sandpaper!!!:eek:
 
So you've narrowed it down to crappy and/or contaminated belts. What kind are you using?
 
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