Another 3M microfinishing ?

Varga Knives

Varga Knives

Joined
Aug 12, 2006
Messages
1,302
Hey guys,

I am still feeling my way around belt selection, and what works best for me, but I think I am doing okay up until 400 grit. Aside from cork and SB (which are both fantasic btw), the only belts I have in higher grits are 3M Microfinishing from 400 to 1200. After 400 in either the Gators or J-flex I have what appears to be a very nice and FLAT finish. But the problem is when I try to progress higher with he 3M Microns I only contact the middle of the bevel.

My assumption is that the others belts are thicker and are giving me a slight convex while the 3M's are thin and truing-up the flat grind. I am perfectly content with the imperceptible (to me anyways) convex the other belts leave but should I be knocking down the middle of the bevel with the 3M's or go to a backing belt? The former seems like it really isn't worth the trouble and the latter means one more thing to buy. Maybe I'll see if I have an older belt that is a little bit shorter and run it underneath. I really want to use these belts so what should I do? I don't have a rotary platen but I could take off my flat platen and slack grind but I'd like to avoid emphasizing the convex on some of the thinner blades. Temporarily add graphite on top of my glass platen?

Thanks!
 
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Anyone? I did search and read the old threads associated with the same general issue but I didn't find anything close enough to help.

Sorry about the bump but I have a couple of blades I'm not sure how to proceed with.
 
Strider, I'm probably not the guy you're looking for, but I'm realizing that it's very difficult to get true flats on a belt grinder- a disk will make it much easier.
That saidI've gotten pretty darn good results with the Norax belts, I have down to 5 micron, and they have a little more substance to them than the 3m films, so they ride much better on the platen.
Used to use the 3m, but went to Norax and never looked back.
Now if I could just make time to finish my new grinder build so I can slow the belt down....

PS. 3m is making something very similar to the Norax now
 
I'd stick to using those belts for sharpening, be sure to sand down the lap joint area for best results.

They are OK for hollow grinding but I have never had good luck with them. I would use gator belts up to 600 grit and probably hand finish after that instead. Cork belts (after the gators) with compound work pretty well for a higher finish too.
 
I have dozens of 400-1200 grit belts hanging on the wall. They look good there....because they never go on the grinder. I have found that above 400 grit you can't get a finish worth a darn on a grinder. At that point you have to either hand sand or accept a matte finish. I usually follow the 400 grit belt with a Scotch-Brite belt and call it done.
 
Okay, thanks guys. I actually used these belts for sharpening last night and got some really nice results. I'll probably pick up some Norax belts on my next order. So far I have had great results going from 400 to the SB belt so I'll just stick with that for now. I'm not a big fan of mirror finishes but I would like to try and get a mirror finish using just belts and I'd like to emphasize the word "try". I can wait on that though.

Thanks!
 
strider214 said:
Okay, thanks guys. I actually used these belts for sharpening last night and got some really nice results. I'll probably pick up some Norax belts on my next order. So far I have had great results going from 400 to the SB belt so I'll just stick with that for now. I'm not a big fan of mirror finishes but I would like to try and get a mirror finish using just belts and I'd like to emphasize the word "try". I can wait on that though.

Thanks!
Click to expand...

Waste of time trying to mirror with belts. Call Brownell and get some medium felt wheels and compounds from 320-555.Use the 555 on a one inch wide loose muslin wheel.
Take a look at the flats on old-ish semi autos, single shots and lever guns. Pancake mirror.
 
I have some 3M Micron belts and I found the only thing I use them for is polishing the tang edges. I tried using them on the bevel and flats, and it was just a nightmare.
 
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