What belt backing do you use for finer grit belts when grinding bevels?

S

SamaraVolk

Joined
Apr 17, 2014
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I've been reading a lot of posts how makers got to say 600 grit on their bevels prior to heat treating. I can't get past a x back 120 grit without the blade "chattering" off of the platen. I only have a fixed speed grinder (4100 FPM or so). Can this be the problem? I have no problems at 40, 80, or 120 heavy backed belts. Thank you
 
I only have a fixed speed grinder (4100 FPM or so). Can this be the problem?
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Yep, that's a big part of the problem right there - too fast for fine grits. 600 grit (even 320) works so much better at 1,000 SFPM - well, maybe some faster, but the finer grit, slow belt speed.

Ken H>
 
With the belt installed on the grinder and the belt splice centered on the platen (motor off), try abrading the splice area with a diamond hand pad, such as http://a.co/5Uydjlt

This will help alleviate chatter caused by the increased thickness of the splice.

Recently I switched to wet grinding. In addition to the water stream that cools the work, I have a little jet of water spraying behind the top platen wheel. That water (intentionally) gets in between the platen and the belt. It cools the platen and makes everything run smoother.
 
What kind of fine grit waterproof belts have you found?
P.Brewster said:
With the belt installed on the grinder and the belt splice centered on the platen (motor off), try abrading the splice area with a diamond hand pad, such as http://a.co/5Uydjlt

This will help alleviate chatter caused by the increased thickness of the splice.

Recently I switched to wet grinding. In addition to the water stream that cools the work, I have a little jet of water spraying behind the top platen wheel. That water (intentionally) gets in between the platen and the belt. It cools the platen and makes everything run smoother.
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Claude Bouchonville uses the graphite cloth on his platen. He goes up to like 400-600 with belts and then to his buffer. He has a fine Scotch Brite flap wheel on one arbor and a hard buffing wheel with white compound on the other one.
 
What kind of grinder and platen do you have? Do you have a ceramic glass liner?
 
I use ceramic backing on my platen and I have good results but I also have a variable speed grinder to slow down on finer grits.
 
kuraki said:
Aren't trizacts waterproof?
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I believe they are supposed to be used dry, or at least that a common disclaimer on the usaknifemaker site. I think water makes the grit come off or something.
 
The trizact gator or cf (rectangular and thick structure) will fall off of you use water. The thin regular trizact won't and can be used with water. Easy way to remember is the thick is non water, the thin is water.

The chatter issue is bad over 120 grit if you use X weight. I have ceramic and use J weight, it helps a lot. Try the klingspor or merrit. I rarely flat grind though, so no issues with chatter on my rubber contact wheels no matter the belt or grit. If you want to go up to 800-3k grit there are some belts that won't work on a platen like the deefros, they will breakas son as you put metal on it because they are so thin.
 
Thanks for all of the info guys. I am waiting on a VFD and will more than likely have to change my GFCI in the garage for it to work. I'm hoping a lot of my problems; chattering, burned wood scales, insufficient sharpening capability, small wheel use, etc will go away.
 
I can echo what others have said in the thread. I have both the thick and thin gator belts and if the thick ones get moderately damp they will definitely lose their grit. On the other hand my thin 1200 grit gator belt has been soaked before and still works great.
 
Pittknife said:
The trizact gator or cf (rectangular and thick structure) will fall off of you use water. The thin regular trizact won't and can be used with water. Easy way to remember is the thick is non water, the thin is water.
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That's interesting... I've had just the opposite experience. I have used the thick gator trizacts for about 3 years now, sopping wet and never had an issue with the grit coming off. On the contrary when I try the higher gritted thin gator trizacts they seem to fall apart (only tried once or twice with these). I'll have to try it again... I am generally running these at about 1500-1800 fpm though, so that may be part of it.
 
kuraki said:
Aren't trizacts waterproof?
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I use them wet and have no problems. They seem to last forever dry and dont last as long wet but they hold up a good while for me when used wet.
 
I recently bought my first cork belts to try and haven't used them yet. Is water bad for them? I don't have a wet setup but dunk a lot post heat treat.
 
MBurks said:
I recently bought my first cork belts to try and haven't used them yet. Is water bad for them? I don't have a wet setup but dunk a lot post heat treat.
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I don't use them wet but use them like you're describing. No problem. Use a little green chrome on them and they don't heat up quite as fast. The wax gives the belt/blade contact a little more slick. And the polish helps the appearance of the finish. They're wonderful belts for machine finished knives.

One of the things that always gets me when trying to do a machine finished knife is that no matter what grit you're at, a normal cutting belt can really screw your grind up with a single slip, causing a divot, screwing up your plunge, etc. That's what makes the cork belts so nice. The cork basically protects the blade from gouging if you didn't hold it just perfect. My confidence in a belt finished knife is ^^^^^ higher since using cork.
 
kuraki said:
I don't use them wet but use them like you're describing. No problem. Use a little green chrome on them and they don't heat up quite as fast. The wax gives the belt/blade contact a little more slick. And the polish helps the appearance of the finish. They're wonderful belts for machine finished knives.

One of the things that always gets me when trying to do a machine finished knife is that no matter what grit you're at, a normal cutting belt can really screw your grind up with a single slip, causing a divot, screwing up your plunge, etc. That's what makes the cork belts so nice. The cork basically protects the blade from gouging if you didn't hold it just perfect. My confidence in a belt finished knife is ^^^^^ higher since using cork.
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That sounds great. I generally hand sand everything for that reason, I always have a little flaw from grinding, and I've thrown some away trying to chase them out.
 
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