remove tiny little scratches / hand finish

IH8U

IH8U

Joined
Mar 6, 2007
Messages
779
I'm finishing up my 3rd knife and I'm having trouble removing tiny little scratches. I'm working with 1095, did my initial grinding up to 120 grit and it looked pretty good after the heat treat. I did some decarb and noticed some deeper vertical scratches. I tried 80 grit by hand and it doesn't remove any material so I went to 120 and continued by hand. After 2+ hours and half a dead arm I'm still left with some minimal scratching. I want this blade to be my best one and I'm personally not satisfied with the remaining scratches.

So I guess what i'm looking for is:

1) anyway to get the buggers out, besides countless hours of hand rubbing?
2) anyway to hide them a bit without coating, etching maybe?
3) what is the best process for hand finishing?
 
Have you tried using any sort of lubricant like WD-40 to speed up the process? Are you backing your sandpaper with a very hard and flat material? Also, do you have your knife secured to a bench or table somehow? All of those will help with hand sanding quite a bit.
 
Hi - I grind all of my blades to 400 grit minimum before moving into any polishing/sanding stage. 80 grit sand paper will not be easy to finish a blade with. I usually start one grit below where I stopped on the grinder, meaning 220 or 320 if I stopped at 400.

I always use a lubricant, as mentioned above, usually tap magic or simple green. The simple green is healthier for you. I also use a sanding block and a vise, as already mentioned. You want to use quality wet/dry silicon carbide sand paper, not brown/red aluminum oxide paper. If you're having trouble getting an even finish with 120 grit sand paper and the process outlined above then the finish was too rough at the start or the sand paper isn't the right kind/quality.
 
Take a buffing wheel and some 80 grit compound :D Will remove pretty much a lot of stuff....then go to 400 grit.
 
Whenever I have to clean up a blade after HT I use the machine to 220 then start hand sanding. For me the steel is too hard to remove metal efficiently with anything under 220. Hand finishing... I use a granite slab with paper spray glued to it for the ricasso. For the bevels I clamp the blade to a piece of wood profiled to the shape to overhang the workbench and hand sand with a piece of PG scrap blade steel. Files with paper wrapped around em work too, but I tend to screw up and drag the file by accident. I use Simple green and water. Some use windex, some WD40.

Do not bend over and poke yer head with the blade clamped up on the workbench, some folks have done that. I have stabbed my hand with the tip of the blade. Even unsharpened, it sucks sometimes.:mad: You drop your sandpaper or block, then there it is in yer face.
 
all great suggestions, much thanks!

I was using spit as lube and cheapo sandpaper. I'll grab some better stuff before heading home for the day. Backing the paper will probably be useful as well.

I have to order some 220 and higher belts on my next order, all I can find locally for my POS 1x30 is 120 (time to sell some of my collection for a real grinder). I have some rubbing compound and a buffing wheel, but I'm unsure of the grit, but giving that a go seems easiest on my arms.
 
Home Depot and the other stores usually have decent Norton papers up to about 400x, if there's an auto body supply place nearby they will have good wet dry paper in little "job packs" so you don't wind up buying it 50/100 at a time like some of us :p If you eBay at all there's Barbkat and Bullet Industries that have good deals on decent to good paper.

I use some flat mild steel as a sanding block for my "grunt" work then move to a micarta with hard leather on my final finish. A lot of guys swear by the hard rubber sanding blocks ( I know some that use a hockey puck cut in half) for their final finish. I'm going to try that sooner or later.

I go to 220x before HT, I use ATP 641 to control scale. If you have satanite or some other similar refractory you can make a thin wash to use as a scale control for heat treating. 1095 is a bear at times anyways, a lot of my first blades were 1095. Don't be discouraged, the first grits are the hard ones, you'll feel like you're not making progress then all of a sudden the finish POPs at you. Hang in there, remember we should be called "knifefinishers" instead of knifemakers. :D
 
Good sandpaper helps alot, IMO. The norton from Home Depot beats the heck out of the cheap stuff from Harbor Freight, and the real "good stuff" is probably even better. I have been backing mine with a piece of wood, but if you have metal or micarta it would probably work even better. You'll get an uneven finish and it'll take forever if you don't use some kind of backing and if you don't clamp the blade down. I usually put a piece of 1x2 wood in my vise and then use vise grip pliers to clamp the blade (tang) to the wood, works pretty well, and allows for easy removal to check scratches in better light, or to switch sides of the blade.
 
Another thing that helps... I try to hand sand one side of the blade all the way up to the finest grit I plan on using, then cover that side with good masking tape before you flip it over. There will be plenty of grit and steel dust on the backing board to scratch up all the hard work you just did....

-Mark
 
I go to 320 pre heat treat. After heat treat, 320 on the grinder. Then I back down to 220 (by hand, and all following sanding is by hand), I work it real good with this. Then I move to 320. After the 320, I use 400 at a 45 degree angle. Sanding at a different angle lets you see the scratch marks from the previous grit. 600 at 45 degrees the other way, then to 800 parallel to the spine again. I alternate directions until what ever final grit i want, then buff if desired. If I want a satin finish, I go one grit higher (usually 1000 or 1200) then use 800 (dry) to apply the satin finish.

Look at it under different types of light. Sometime I see stuff in sun light and incandescent that I don't see with a fluorescent("greenie" bulb with mercury for added toxicity and mental instability).

I usually like to use WD40 or TapMatic (Aquacut, Grainger cat no. 2C649).

Lots of patience. Sand paper is relatively cheap. Don't be afraid to go back to a rougher grit to get some of the scratches out.

Ric
 
I actually grind to 400 prior to heat treat AND hand finish to a quick 400 prior to heat treat. That way, I can get all of those pesky deep scratches that love to booger up your finished blade that were put there by new, lower grit belts. Good tip about using multiple light sources. I use a halogen lamp during sanding, check it periodically with a flourescent bulb, and also use sunlight.

Yeah, you may have to remove scale after heat treating, and I do this with a light touch and 400 grit paper. The hardened blade will be less likely to get deep scratches and the pattern will be more uniform. Then I start sanding at 220 or 320 depending on how much grinder work was required after heat treating. I use a piece of steel covered in leather to support the blade off the end of my work bench. It is tapped and has screws coming up through the steel into the leather that create little bulges in the leather to support the tapered blade and prevent springing while sanding. I use a piece of angle iron ground flat as a backing stick to start, and then a piece of angle iron with leather to finish some pieces. I use a cheap honing oil I bought at Lowes to keep the grit in play.

You can get higher grits of paper at your local auto parts store (autozone, advanced, etc) in the paint section. I typically finish anywhere from 400 to 600 or even 1000 grit.

--nathan
 
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