Prepping for hand rub

M.Griffin

M.Griffin

Joined
Nov 8, 2007
Messages
460
I am looking for some suggestions as to what combination of belts works best for you when preparing to hand rub up to 800 or 1000 grit. I am wondering what grits and brands of belts are used most effectively. Right now I am using blaze belts to rough everything in, then going to 220 Norton Norzac, and finishing with 400 J-flex. I know the j-flex probably isn't ideal, but it is what I have. Then I go back to 320 to start hand finishing. This has been taking me forever to get the scratches out. It is making me crazy.

The discussion on how great the gator belts are in higher grits got me thinking I should be on the grinder to 600 or 800, then stepping back to 400 to hand finish. I am just using way too much shop time hand sanding. I know it takes a lot of time, but I think I am doing something wrong. Thanks for any input.

-Mike
 
Mike,
Hand rubbing in the lower grits DOES seem to take forever.... 600 and higher seems to go faster. I would hazard a guess that there may be scratches from coarser belts being left in the blade. I normally work a belt at slightly different angles (except around the plunge) to see where there are scratches hiding.

Using a hard backing (I use a mild steel bar) and an oil lubricant (I use baby oil, some people use WD40, simple green, ect) at the coarser grits. Another thing I was guilty of was trying to save money using paper for too long. 320 and 400x papers only get about 10-15 passes and I'm moving on to a fresh spot.

At higher grits you may want to use water as a lubricant. There's a saying "oil cuts, water polishes" seems strange but experience has proven it to me.

I don't normally go over 400-600 as a finish for a user unless requested.
 
Mike,

I can't tell you about belts. Hand sanding with paper is a lot better with a cutting fluid. Tool & Die/Mould Maker polishing stones are a lot better than sand paper with cutting fluid (usually used with deodorized kerosene).

Falcon Tool Co. http://www.falcontool.com/ has a deal on 5lbs. of irregular/broken polishing stones if you want to try them. You won't get some of everything but the price is right... $15. Falcon is also a great place to get files from.

Mike
 
i come off the belt grinder at 400 grit then i got to the disc sander at 320 i then go to handrubbing at 220 with simple green or orange magic or something of the sort then 400 600 etc. a complete 4" hunter from the time i start handrubbing to completion at 600 takes around 1 hour.
 
Do NOT start hand sanding with anything coarser than 180. YOu will spend 60% of your time trying to gt out the 80 or even 120 grit scratches. Once you get above 220, it goes pretty quickly. I used to start with 120 and now start with 180 going lengthwise and using Cool Tool 2 or Tap Magic cutting fluid. The only reason I start with 180 is because I usually stop at 220 on the grinder on flat grinds.
 
I usually start off with a good hand rub as the prep and then move on to...
Oh wait, wrong forum:rolleyes:
 
I always start my hand rubbing with 120, then 180,220,400,500,600,800, and it works for me here. Its something you need to play with and see what works for you. Hope this was of help. :thumbup:

Terry
 
I grind up to 400. Then I back down to 320 (sometimes 220 if the grinder scratches are looking un-pretty) with paper and some cheap honing oil to lay my foundation for hand rubbing. Then 400, 600, 800, 1000 up to how ever high you'd like. I figure out my finish grit and know it will run parallel to the blade, and I alter the rub angles for the previous grits. Usually if I finish at 600, I'll start with 320 lengthways, 400 at a 45 degree angle to the edge, and 600 lengthways, making sure you remove all the previous scratch marks before continuing to the next grit. Depending on how it's looking, I sometimes go up to 800 lengthways and then back down to 600 to finish.

--nathan
 
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One more thing. I tip that I got from Dr. Jim Lucie was to go one grit higher than you final finish and then come back with your final grit paper and a hard rubber block of some kind and pull from ricasso to tip. Use the corner of the block and for each stroke, move the paper a smidge so you have a fresh spot for each stroke. Unless I mess up and get a wiggle, it usually takes me less than twenty strokes per side to get the final scratch pattern nice and straight and even. I wet sand for all of my grits except for the final one, so, in effect, I am backing up more like 1 1/2 grit levels because wet sanding seems to leave a finer finish than the same paper when used dry.
 
A very important thing is the lighting. I use 6500 K white Compact Flourescent Light Bulb on a "robotic arm" (I dont know the exact term of it) work lamp and head set magnifier. You need to investigate the scratches at different light angles. I was not doing that but after I bought a head set and a good work lamp the quality of my hand rubbed finishes increased real good...

Edit -add: I found very frustrating to get rid of irregularities from belt grinder by hand rubbing started from 220. These days I usually finish at 80 :eek: on my belt, then make all the blade flat with blue 120 grit hand rubbing, then return to belt grinder and only remove the scratches of 120 with a dull 220 a couple of minutes. Then continue hand rubbing starting from 400. I dont use 400 grit belts I bought since then... Hand rubbing took about 1-2 hours for a 4" blade per side. With this method I only spend 30-40 mins on whole blade...
 
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I agree on the light. I have good lighting where I hand sand and a quality flash light. I wear an optivisor with 2.5 magnification and take the flashlight and shine the blade from every angle.

Also No one responded to Fitzo question about which steel. It is a lot different hand sanding D2 than say 5160.
 
I can really second the lighting suggestion.

Last Sunday I was finishing a sword blade. It was to be full polished and engraved. I machine sanded it to 800 and took it to a brilliant polish on the buffing wheels. I was polishing at night in the outer area of the forge....100watt fluorescent lighting. When I was engraving it on Monday, I noticed some fine scratches. With a closer and magnified view I saw that there were still the "ghost scratches" from earlier grits. The blade looks like a mirror until you get it at the right angle and look close. Since I was already started with the engraving, I finished the blade. This was not a fatal problem, and may even rub out some with final hand polishing, but it probably would not have happened if I was wearing my Optivisor and had the good lighting on.
Stacy
 
Will Leavitt said:
At higher grits you may want to use water as a lubricant. There's a saying "oil cuts, water polishes" seems strange but experience has proven it to me.
Click to expand...

Will, not be difficult but I think it's the other way around: Water cuts, oil polishes. ;) But now you've got me questioning everything I know about hand finishing...

One of the things that often gets overlooked in these discussions is an idea that Bruce Evans suggested several years ago. Get a quarter sheet palm sander, replace the plastic or rubber platen that comes on it with a Micarta one. You can round the edge of the Micarta platen to match your typical plunge radius to get into the plunge. Using this will cut your hand sanding time by 75%. You have to be very careful to keep the sander flat! And watch out for the edge; you can quickly put a sharp edge on your knife without knowing it. No need to disclose how I learned that.

I take it to 400 on the grinder and back off to 220 when I start "hand" sanding. I use the palm sander to one grit higher than my intended final finish, and use dry paper on the edge of a softwood (like pine) block for the final rub. Seems to work okay for me. I use windex as a cutting fluid for 220 and 400, Cool Tool II for higher grits.

One final note. Probably because I started getting interested in handmade knives in the 70s, I still take most of my knives to a mirror polish. I've found that there is no substitute for hand sanding; I simply cannot get a good base finish for polishing on the grinder, regardless how high a grit I take it to. There are always hidden scratches in the blade that I can only remove by hand sanding.
 
ddavelarsen said:
Will, not be difficult but I think it's the other way around: Water cuts, oil polishes. ;) But now you've got me questioning everything I know about hand finishing...
Click to expand...

Is it? :confused: I hand rub using baby oil until I get to higher grits.... I'm going to try it the other way this time.

I'm serious, for years I've used baby oil until I get to my final grit. At least it's not a hard change to make.

I've used a Bruce's palm sander method with vary amounts of success. I still try it about every third blade or so. Probably if I made a commitment to it I'd get it nailed.
 
I've been toying with a palm sander with sporadic success. My theory is that if your bevels are not very flat to start from filing or grinding, that it's not going to work to any great degree.

To the discussion about the steel type, would 5160 be much more difficult and time consuming to sand than say O-1? I'm new at this, and my first blade was 5160 and took way longer than a later blade of O-1. However, the 5160 blade was filed by hand and I suspect not very flat, while the O-1 blade was done on a grinder and presumable more flat.

Also, when doing the final rubbing with fresh paper on the corner of a backing tool, where do folks start? I presume in the plunge, but when I do this I end up with hooks in the plunge (or wherever I make initial contact.)

It must be taking me a minimum of 3-4 hours, and in certain instances (the 5160 hand filed blade or example) much, much more. I would be in heaven if I could get this down to 1-2 hours!
 
I usually don't put a mirror finish on my blades except when a customer asks for it. This is how I do it.
I take the blade to a 220 grit finish on the belt and switch to 4 different stones with the last being close to 600 grit. I get the blade nice and flat with this method. I then go to 320 grit paper. I use a piece of micarta that is 12" long by 1-1/4" wide and draw file so to speak the blade from the ricasso to the tip. This evens out any sratches left from the stones. I change over to 400 using the same micarta block at 45 degrees. From then on I go through each grit length wise on the blade using windex up to 1000 grit. I then change to small 1"x1" pieces of 1200 grit glued to a spong pad. This I do with my thumb being sure I continue in the same direction of the other grits. I inspect uner a good light source (sunlight is best IMO) and make sure there are no swirly marks left from the paper stopping and then starting again. It's best to try to keep the paper in motion on a straight path. I finish with rouge on a buffer and check in sunlight to make sure there are no imperfections.
The most important thing is to inspect between each grit to make sure that you have removed the last grit scraches completely or they will show up during the final grits and stick out like a sore thumb if you buff.
 
P J 234 said:
To the discussion about the steel type, would 5160 be much more difficult and time consuming to sand than say O-1? I'm new at this, and my first blade was 5160 and took way longer than a later blade of O-1. However, the 5160 blade was filed by hand and I suspect not very flat, while the O-1 blade was done on a grinder and presumable more flat.

Also, when doing the final rubbing with fresh paper on the corner of a backing tool, where do folks start? I presume in the plunge, but when I do this I end up with hooks in the plunge (or wherever I make initial contact.)

It must be taking me a minimum of 3-4 hours, and in certain instances (the 5160 hand filed blade or example) much, much more. I would be in heaven if I could get this down to 1-2 hours!
Click to expand...

Steel type does really make difference. I dont know about O1 but I worked on W1, 5160, D2, RWL34. I first started knifemaking with a piece of D2 and I used to the process. But when handled a carbon steel it was like heaven. A hard piece of 5160 grinds like soft annealed D2. Recently I play with RWL34. I couldn't believe, these powder steels grinds like a butter when annealed, but after hardening it takes ages to finish (but better than D2, I have a love-hate relationship with D2 :D)...

I guess the real answer is experience. I had those J hooks, then I slowed my rubbing speed and inspected what was really happening where hooks formed. I trained my hand not to pause even a bit and start grinding before the sanding block touches the steel. My success key was that...

Again experience is important to minimize the sanding times. Before I bought a micrometer i was not sure why some parts of the blade takes too much time to grind. Now I measure almost every flat point of my reed knives before hand rubbing (those knives have to be full flat before beveling and have to have a precise angle). I make sure there are no mounds or holes. For usual knives it is enough to paint the blade and sand with a flat piece of sanding block until you remove all the ink...
 
galadduin, I appreciate the advice. I'll try and start the motion before I make contact with the steel to see if that helps. Do you make your initial contact in the plunge, at the tip, or ???
 
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