Material choice and finishing question

J

Josh_B

Joined
Jul 13, 2015
Messages
7
Hi,
I am fairly knew to knife making, and have only made a few so far. I have mainly used O-1 tool steel. When trying to clean and polish a knife after heat treating, I'm having difficulty getting it to where the grain cannot be seen. I have tried block sanding with various grits and using a sisal wheel with different compounds. The sanding helps to a degree, but I cannot totally get rid of the appearance of the grain in the steel. I'd like to have a nice, uniform appearance. I am wondering if I should use a different type of steel, or use different methods for cleaning up and finishing.

Thanks for your time and advice.
 
Not really sure what you mean by you can "see the grain", but I suspect you are talking about the directional structure that you see in the steel when it is rolled out. Regardless, try alternating your scratch pattern every time you change grit. For example, using 120 grit, sand at a 45° angle. Once that is done, and the scratch pattern is even, move up to 220 grit, and sand at the opposite 45° angle. Sanding in alternate directions allows you to see any scratches from the previous grit and get rid of them. Move up to 400 grit, sand at the opposite 45° angle. On your final grit, sand lengthwise. That's about all you can do, alternate scratch patterns. I stop around 800 for EDC and hunters, 1200 for kitchen knives, but that's your call. You can even try to mirror polish, if that's your thing.
 
Go higher in grits, but don't miss any previous grit scratch before going to the next one.
As suggested alternate direction between grits.
Go google youtube for sanding 101 by Nick Wheeler....hand sanding bible :)
 
Thanks guys. Is this something that you have to deal with, regardless of the type of steel used?
 
Yes it is, but please consider that steels with an high carbide volume require more efforts than simpler steels, due to increased abrasion resistance.
O1 falls somewhat in between the 2 categories, maybe more on the easier side.
Anyway it is easier to sand before hardening, and with the right protection during heat treatment you may have only the final step of finishing afterward.
On the contrary, without effective shielding from the forge/kiln athmospere you can mess the steel surface so much it become then very difficult to finish.
 
OK, great - thanks again. I did watch that Nick Wheeler video last night. It did provide good insight.
 
here is some 01 that I did recently, hand sanded and then scotchbrite.

Is this representative of what you want or the problem you are having?

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I personally like a finish where you can see the even sanding as long as it's consistend and crisp (like the one above). i only satin down to 2000 grit when it's a special project and hardly ever mirror polish. to me i like steel to look like steel and IMHO that's what steel looks like... if that makes any sense, lol
 
Those are some nice knives. Here's a picture of the one I was working on, and the "grain". Try to ignore the light scratches which are from me sanding with too high of a grit sandpaper. You will notice that there is "grain" running lengthwise. I think it kind of looks like wood grain. This is O-1 steel that has already been heat treated at this point. The grain got a little better with sanding, but it seems like it would take a lot of sanding to totally get rid of it and have a uniform finish.

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I don't see a grain, I see deep coarse scratches running lengthwise in addition to the light scratches you see.
 
maybe you could detail to us the grit progression you are using?
that might help us better understand
 
I was using 220 - 400 grits, which now I know I should have started lower. It's been about four months since I worked on this knife. I am beginning to wonder if I did something like lay it flat on my belt sander... Let me ask this -- it is uncommon for O-1 to have this "grain", correct? If so, that will encourage me for the future and I will keep learning and keep trying.
 
Josh_B said:
I was using 220 - 400 grits, which now I know I should have started lower. It's been about four months since I worked on this knife. I am beginning to wonder if I did something like lay it flat on my belt sander... Let me ask this -- it is uncommon for O-1 to have this "grain", correct? If so, that will encourage me for the future and I will keep learning and keep trying.
Click to expand...

i've only made about 15 knives, all are out of 01, none of mine had this "grain"
 
Ok -- seems like I probably unknowningly scuffed it up. Thanks everyone for your input. I'll keep at it, and glad I did learn more about proper hand sanding technique through our discussion here.
 
What I see is the scratches from pre-HT that are deeper than the finishing grits.

Start off by taking the scratches out BEFORE HT. Sand to a really good 200 grit, or even better - 400 grit. Any deep scratches left before Ht will be very hard to remove once hardened.
After HT go back to 120 grit ( 220 if you sanded to 400 grit pre-HT). Don't go back up the finishing grits until the surface is free of all pre-HT scratches.
 
Josh,

I think that I see what you are talking about and it could be that the knife is not flat. Lots of guys buy their stock precision ground or surface grind their stock themselves to solve the problem. The bright areas are the high spots where your finer grit sandpaper is taking off steel. The dull areas are the valleys where you have yet to remove either the mill scale or the decarb from heat treat.

Try this to prove if this is the correct assumption. Use a black sharpie to color the side of the knife, then lay a sheet of sand paper on a very flat surface(granite block, corian, sheet of glass) then lay the knife on the paper and sand the surface that you blackened with marker. The sanding will remove the sharpie from the high spots first; see if this doesn't correspond with the "grain pattern" that you are seeing.

I think you are in for a whole lot more sanding before this knife becomes what you envisioned. Take your time and stay with it, you'll get there.

Cheers.

Jeff
 
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