what would I use a scotch brite wheel on my bench grinder for?

M

Maelstrom78

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Sep 21, 2013
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Seems like I hear about makers who use them for things. On the show where they make the fantasy blades (man-at-arms)it seems like they use the Scotch Brite after only maybe 220 or 320 grit then they go to the buffer and they seem to get a good finish on their blades.

I've been mostly going to 220 or a A65 gator after heat treat and then working my way from a 400 grit cork belt all the way to a thousand grid cork belt and then any hand sanding I was going to do. do I have anything to gain by switching to scotch brite at any point?

Thanks!
 
I could see a wheel being useful for getting into tight areas like the plunge where a normal scotch brite belt couldn't get to. Even then you could probably just run the belt off the side of the platen and get up in there. I don't really see the advantage to using one, but then again, I'm wrong about a bunch of shit.
 
My number one use of the Scotch-brite wheels is when I'm putting a mirror polish on the front face of my bolsters. I shape the pair together on the rotary platen progressing from 50 to 400 grit. I then clean all the 400 grit marks off on the medium (red) wheel and then remove all the red wheel marks with a fine (gray) wheel. I then polish on the big buffer with green compound and bring out the final shine on my smaller buffer with white compound. At that point it is an absolute mirror polish; I hardly bother looking for scratches anymore. I also use the wheels to gently break the edges on the spines of blades. I just posted this knife in another thread but, these bolsters were finished with a loose red 4" Scotch-Brite wheel. It's a jeweler's wheel I got from Rio Grande. The bolsters are heat colored Zirconium.

Untitled by Ranger_Bob, on Flickr

Bob
 
I have seen a very well known knife maker from Europe go from 400 grit belts with a graphite cloth backed platen to a Scotchbrite flap wheel and then to a buff with white compound and get a very nice finish.
 
We use scotchbrite wheels and a 1" wide by 6" diameter cratex wheel on bench grinders (the ones from lowes with the variable speed). We use the rougher ones for removing forge scale. The cratex and the finer scotchbrite are used to finish guards, quickly touch up spines if they get discoloration in marking. I sometimes run the corner of the wheel into my plunges before the last belt to really shine them up. Very useful. BUT!!! I do not use the ones available at the knife suppliers. Go to encotool and get silicon carbide ones that are hard! The knife suppliers sell aluminum oxide in a softer medium and they are so friable they disappear too quickly. Enco has a wide variety. Remember to get the middle piece. The hole is 3" and the shaft is .5".
 
Solid scotchbrite wheels are great for de-burring parts. Don't think I'd use it for finishing plunges. It's easy to unintentionally round edges or cause a wave in a flat surface that will be difficult to remove.

I have one machine set up with loose scotchbrite (probably like what Rangerbob mentioned). This is great for finish of plunges and getting into contours where you want to preserve surrounding edges. The scotchbrite is soft, like the hand pads, and you can stack the discs or buy a wheel made up of several layers. Looks like this:

View attachment 532098

You can easily get a nice, even transition between the bevel and tang/ricasso section when the satin 'scratches' are intended to run perpendicular to the edge, matching the bevels:

View attachment 532100

Scotchbrite belts are also useful.
 

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Huh, interesting. It seems like they have different densities? It looks like there are hard wheels and soft wheels like Fiddleback alluded to. On the 3M site it looks like they have cutting wheels and ones that are more like polishing wheels. Cratex must be a similar product.

I don't know if I gain anything vs. using the cork belts I already have but dang it if it helps with getting a good finish in the plunge or some other little hard to get area that would be worth it.

Aaand I get to buy some more tools yeah! And I assume Fiddleback you use them on forge scale as they are more economical than burning through good belts?
 
I use them on my guards of my hidden tangs. I go from 120 to a hard scotchbrite, then to green buff and done. If you leave it at the a scotchbrite, it's a pretty fine satin. Eases corners and polishes ball peins. They are handy
 
Maelstrom78 said:
Huh, interesting. It seems like they have different densities? It looks like there are hard wheels and soft wheels like Fiddleback alluded to. On the 3M site it looks like they have cutting wheels and ones that are more like polishing wheels. Cratex must be a similar product.

I don't know if I gain anything vs. using the cork belts I already have but dang it if it helps with getting a good finish in the plunge or some other little hard to get area that would be worth it.

Aaand I get to buy some more tools yeah! And I assume Fiddleback you use them on forge scale as they are more economical than burning through good belts?
Click to expand...

There are different densities of solid scotchbrite wheel available.
Hard,medium,soft... Plus, different compositions to handle different materials.

A "soft" solid SB wheel is NOT the same as the loose SB discs or SB flaps (another variation), and will behave very differently. Those loose discs are floppy like SB hand pads and conform easily to contours. Even a "soft" SB "wheel" will not conform in the same way.
Cratex is something else entirely. It's a rubberized abrasive available in different grits. Also handy for certain things.
I like variable speed on the floppy SB discs and Cratex. Most bench grinders are just way too fast and will burn up your discs/flaps faster than necessary. Solid SB wheels seem to handle the higher seed better.
SB Wheels aren't particularly cheap, nor is Cratex.

I always burn off forge scale with hydrochloric acid (pool acid) before grinding. That saves on belts.
If you can swing it, get some of each of these and try them out!
 
Yea, the forge scale will kill belts. I get it off quickly with scotchbrite wheels, others use acids (pool acid, vinegar, etc).
 
cratex, btw, is abrasive imbeded in a rubber like substance. Works kinda like a pencil eraser cleaning a coin.
 
I have a 320 grit hard wheel from red hill (best price) and it is great for guards and other furniture, use it on the spine and ricasso too
 
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