Belt progression advice

G

GiantIsHere

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Mar 22, 2016
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So I've watched a lot of video and get that we move from course to more fine belts as we work our way to the final product.

So far the Norton belts are amazing.

Can someone please tell me a typical Norton belt progression from most course to most fine?


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Most start with either 32 or 60 grit and then roughly double for each successive grit. 32-60-120-220-HT-220-400-800...for instance. ymmv
 
The norm is to roughly double the grit each progression. It doesn't have to be exact, but that is the usual range.



What is probably more critical is that when using very coarse belts to rough in the profile and bevel, you must assure all these deep scratches are gone before going to the finer grits at the 200 range. I recommend a 120 grit belt until every deep scratch is gone before starting up the path. If you start with a 36 grit belt, you may even want to give it a clean up with an 80 grit before the 120 grit .



Some science stuff and "why" info:
These deep scratches will not sand out on 220 and 400 grit belts, and can come back as ghosts later on. Part of what is happening is the structured ceramic grits of the extra coarse belts have square grains that are cutting little slices of steel away from the blank - very much like thousands of mill bits milling away at it. This leaves tiny flat bottom grooves in the blade surface. These grains are extremely hard, and you are pushing hard against them. This work hardens the bottom of each grain's gouge. To make matters worse, the great pressure and high heat created in this micro-milling can cause the grain size to be larger along that gouge line ( not the same issue as grain growth in HT, but related). What is needed to allow nucleation and grain growth is the addition of energy. You are providing both kinetic energy as well as thermal energy. The result may be thin strands of coarser and harder steel grains among finer grain and softer steel.
Even when you sand the blade down to the bottom of the groove, the place where the groove was is still harder than the steel next to it. You have to completely remove the whole groove, not just reach the bottom of it. If you still see lines and marks - keep sanding until the surface looks even and there are no vestiges of the extra coarse grit. I don't leave 120 grit until this is the case all over the blade. Most of us have had a blade where after HT there are these funny lines that show up as we sand the surface to 1000 grit. They are often the ghosts of large grit where the steel was affected. You usually have to take the whole blade back to 120 grit and re-surface it, then go back up the grits again to remove them. (BTW, normalizing avoids these quite well when used as a part of your HT program)
 
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i usually get every thing set with a 60 then fine tune it with a 120 then move into Gator belts (220, 400, and 600)
 
A belt that almost no one uses is the 180 grit aluminum oxide belt. I keep a few around and just used one a few minutes ago when I did not like the finish the 220 ceramic gave me. I discovered this tiny problem when I used a 100 Gator belt and saw that that my 220 belt didn't get all the minute scratches out. The 180 took out those scratches and I used the 220 for a few seconds and then the 100 Gator and finally the 65 gator. The gator belts are numbered something like 100, 65, 45, 30,and 16 getting finer each time. They are great at finishing but poor at material removal in my experience. A good substitute for Gator belts are the Norax belts and the Hermes cork belts in 220, 400, and 600 grits. Just my opinion. Larry
 
Larry had a good piece of info. Having intermediate grit belts is very useful. I keep 180,280, 320, and 600 grit for those situations where the standard 120/220/400/800 belts just don't seem to work.
 
Once you get to 220, 400 grit greaseless compound and a felt wheel (or a cork belt-you can also reload the 400grit cork polishing belts with greaseless) is a fine addition.
The 400 grit greaseless compound on a worn 400 grit polishing belt leaves a finish that I can only describe as a coarser version of a Nihonto polish-if there's a hamon or other activity it really pops.
 
LARRYZ10 said:
A belt that almost no one uses is the 180 grit aluminum oxide belt. I keep a few around and just used one a few minutes ago when I did not like the finish the 220 ceramic gave me. I discovered this tiny problem when I used a 100 Gator belt and saw that that my 220 belt didn't get all the minute scratches out. The 180 took out those scratches and I used the 220 for a few seconds and then the 100 Gator and finally the 65 gator. The gator belts are numbered something like 100, 65, 45, 30,and 16 getting finer each time. They are great at finishing but poor at material removal in my experience. A good substitute for Gator belts are the Norax belts and the Hermes cork belts in 220, 400, and 600 grits. Just my opinion. Larry
Click to expand...

Pondering this and trying to learn something...the Trizact (gator) 100m is an aluminum oxide 180 grit equivalent belt. I agree that it doesn't cut like an x-weight AO belt of equivalent grit- my theory is that the thickness of those gator scales kind of cushions things. They always seem to make a finer finish than I'd expect for the grit.
The Norax belts appear to be a different type of abrasive- ceramic alumina- it would be fun to try them in 220 (80 grit equiv) and 100 (listed as 150 g.e.)
Edit: I'm not sure I understand the Norton info- it appears to be saying that Norax = AO after all....hmmmm......
 
J W Bensinger said:
Once you get to 220, 400 grit greaseless compound and a felt wheel (or a cork belt-you can also reload the 400grit cork polishing belts with greaseless) is a fine addition.
The 400 grit greaseless compound on a worn 400 grit polishing belt leaves a finish that I can only describe as a coarser version of a Nihonto polish-if there's a hamon or other activity it really pops.
Click to expand...

For the cork belts, which kind of greaseless compound is best? I've seen the compounds available either in sticks or plastic jars and assume the properties of each are a bit different.
 
Tenebr0s said:
For the cork belts, which kind of greaseless compound is best? I've seen the compounds available either in sticks or plastic jars and assume the properties of each are a bit different.
Click to expand...
I buy the greaseless in the white plastic tubes from Jantz-almost loke a cooke dough tube from the grocery store. It's very versatile stuff.
 
Thank you all for a good discussion of grit. Stacy, the science is very helpful! So my question may be obvious but I'm having a hard time removing the original milling from the 440c I purchased for this project. I began with a 120 belt and I'm using the small wheel at the top of my belt grinder to try to flat grind the steel before I grind the bevel. I then switched to a 220, then to ceramic norton belts. After this I cut the blades out, and now I'm hand sanding (with a block) with 220. However I can't seem to get down past the very small pits or gouges which were originally there.

Do I need to go all the way back down to an 80 on the belt grinder to get these out? Do you recommend hand sanding at all? Or am I just waisting my time with that?

SRH
 
I'm sure not Stacy, but my experience with what you are asking about has been that very often even starting with a 36, or 34, or , is the best idea and then go to 60 before 120. As well, I found for me I cut out the blade shape in advance and soak the blades in vinegar or a weak solution of ferric chloride to remove that outside glaze that will destroy even 60 grit belts without much time going by.
Frank
 
I always start with a 36 or 50 grit norton blaze Orange. They will remove anything you need with a quickness.
 
Stacy E. Apelt - Bladesmith said:
The norm is to roughly double the grit each progression. It doesn't have to be exact, but that is the usual range.
......

Some science stuff and "why" info:
These deep scratches will not sand out on 220 and 400 grit belts, and can come back as ghosts later on. Part of what is happening is the structured ceramic grits of the extra coarse belts have square grains that are cutting little slices of steel away from the blank - very much like thousands of mill bits milling away at it. This leaves tiny flat bottom grooves in the blade surface. These grains are extremely hard, and you are pushing hard against them. This work hardens the bottom of each grain's gouge. To make matters worse, the great pressure and high heat created in this micro-milling can cause the grain size to be larger along that gouge line ( not the same issue as grain growth in HT, but related). What is needed to allow nucleation and grain growth is the addition of energy. You are providing both kinetic energy as well as thermal energy. The result may be thin strands of coarser and harder steel grains among finer grain and softer steel.
Even when you sand the blade down to the bottom of the groove, the place where the groove was is still harder than the steel next to it. You have to completely remove the whole groove, not just reach the bottom of it. If you still see lines and marks - keep sanding until the surface looks even and there are no vestiges of the extra coarse grit. I don't leave 120 grit until this is the case all over the blade. Most of us have had a blade where after HT there are these funny lines that show up as we sand the surface to 1000 grit. They are often the ghosts of large grit where the steel was affected. You usually have to take the whole blade back to 120 grit and re-surface it, then go back up the grits again to remove them. (BTW, normalizing avoids these quite well when used as a part of your HT program)
Click to expand...

Quite fascinating Stacy! I am transitioning more and more to a rough grind to about half my ending profile, then finishing up after heat treat, going then from 60/120/220 cubitron.
So I am curious how this 'science' might apply to a hardened blade. When I am grinding a hardened blade I tend to grind pretty wet, and take it in short grind intervals, dipping the blade and spraying the belt wet with a hand pump bottle. Thoughts?
 
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Wet is the best way but take the time to set up a continuous spray system instead of depending on things like a spray bottle . Keep things clean so you don't contaminate a belt with previous courser grit .When the belt is worn out -throw it out ! Worn belts create much more heat !
 
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