Follow up to KMG grinder thread: Which belts to use

kenhills

kenhills

Joined
Dec 17, 2007
Messages
984
Hi All,

Well its been 2 months since I started using my KMG 10 inch grinder. Can't say enough about the machine or Rob Frink who makes them. Great product great guy. A few months ago I was asking about what you thought were the best belt to use and got a lot of different answers so I tried a lot of different belts. So this is what seems to work for me.

Rough Grinding : Cubitron 60+ followed by a Bluefire 120
Intermediate grind: Norton 220 followed by a Trizac A65 (275 grit I belive)
Finish Grind: Trizac A20 followed by a Trizac A5 which if I am looking at the charts correctly is about 1200 grit
Polishing: an assortment of stuff ending with cerium oxide.

So that makes six belts to bring it to a high polish. I actually think that when I start the polishing part it dulls the polish I get from the belts some then I bring it way back up again. Anyway though I would share if it helps anyone. If you have any suggestions or comments please pass them on.

Ken
 
I believe I read Ed carrerty? say he goes from 36 straight to 220. I think I will start doing the same. then use trizact to finish to desired grit.
 
Wow thats a big jump in grits. Never thought of doing that. My original training in this type of work goes back to cutting semi precious stones and I always worked the grit up in smaller steps. Let me know how that works I would like to lose some of the steps if possible.
 
I was doing the same. Then I thought well I am using a high speed belt grinder. How long can it actually take?? When I get my new grinders set up I'll give it a try. Oh, and I've found I like blaze the best for ceramics..
 
When I started I was using a high speed grinder moving along at 3700 feet per min. I was always trying to find the right amount of pressure so as not to burn the metal. When I went to the KMG setup I can now run any where from 1050 to about 3500 feet per min. I tend to do the rough work at 2500 and the finish work at about 1500. I dont burn myself through the leather and tape nearly as much now and at 2500 the cubitron cuts pretty damn fast. 36 grit, man that is course, there has to be an intermediate step somewhere. If it works let me know I would really like to be wrong about that. Ken
 
I move from my roughing belts at 36 or 50 grit, up to 220 gators right away... it works well for me. Heck, SR Johnson has shown how to go from 50 grit to 400 in one step, cleanly and quickly.

Occasionally I'll use a 120 blaze for an intermediate, in the event that I'm finish grinding a wide blade in hardened steel.
 
I go from 60 to 220 then 400 after heat treat. I'll back down to 220 or 320 after HT if I really need to but that's unusual.
 
Salem Straub said:
I move from my roughing belts at 36 or 50 grit, up to 220 gators right away... it works well for me.
Click to expand...

At one time, I started with 60 grit 977 3-M Ceramic, then would go to 220 Ceramic, then to 400 Klingspor on the grinder, then hours and hours of hand sanding through at least 1000 grit, then pull them back to between 400 to 800 grit, depending on the particular blade.

Lately, I have changed to going from a 60 grit 984 3-M (they seem to last a tad bit longer), then to an A-300, then A-160, or sometimes straight to an A100, then to an A-45. (Then it is still hours of hand sanding, only because that's how I finish my blades).

The nice thing about the Trizact belts is that there is NO BELT BUMP to contend with like you find on finer grit regular belts.

Below is a comparison chart that I borrowed from 3-M a few years ago. It may have changed since I got it, but it will give you an idea of how the "A" numbers compare to the standard grits........

3M Trizact Grade compared to the regular grits we are used to:

A5 - 3000 grit
A6 - 2000 grit
A16 - 1400 grit
A20 - 1200 grit
A30 - 800 grit
A40 - 600 grit
A45 - 400 grit
A60 - 360 grit
A65 - 280 grit
A80 - 240 grit
A90 - 220 grit
A100 - 200 grit
A110 - 180 grit
A160 - 120 grit
A300 - 80 grit

Robert
 
This is what I use now... I've used different progressions in the past, and I'll probable make some tweaks in the future.

50-grit Blaze
A160 Gator
120 & 280 Rhynowet Redline on disc.
Hand-Sand

Tempted to add some of the 3M 984s that Robert mentioned to my next order. Seems there are quite a few folks saying good things about them.

Erin
 
yep i like 40-50 grit then dependig on the blending i want ot do i might slow step up 80 120 then gators
the constant tho is gators they are not cheap but you can dress them like a grinding wheel and get freash grit
for hogging i used to liek the blaze but they changed to some kind of + coating and it builds up on my plattens supergrit.com has good cheap belts and is jsut up the road from me
 
This is the best i can come up with as a comparison chart. Sorry about the link I just cant copy and paste this one. Seriously it would be nice if there was one standard. In bouncing around the web all these charts are different. So who do we lobby to make it happen (lol) yea right. Any way here st is as best as I can make it happen.

http://sharpeningmadeeasy.com/grits.htm

You can print it I just cant make it appear here.
 
Some guys start with 36 grit but I like deep hollow grinds and I find that I can't control the shape of my initial grind with 36 grit so I start at 50 grit or 60 grit and jump to 120 grit for a few strokes and then to 180 or 220 and I sharpen up my lines at the plunge and the top of the grind with 320 and send to heat treat. After that I start at 320 and the 400 and finish with a few passes of a new 600 belt before hitting the buffer. I find that finer grits just load up the belts so quickly that my grind starts looking worse. I will buff and look for imperfections or light scratches and maybe go back to 400 for a few passes before buffing again. I like to have belts on hand that are not common like 50 and 180 but I use 320 like crazy because a fresh belt really makes a big difference for me. I like any belt with a stiff backing which gives a better cut in my opinion. Some of the expensive belts that are supposed to out last 2 or 3 cheap belts may not be worth the money..at least to me because I love fresh belts but I try them all. I grind only stainless steel at present and most of it is pretty hard before heat treat. Just my opinion. Larry Lehman
 
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