Newbie finishing questions

southriv

southriv

Joined
Feb 28, 2002
Messages
751
I ‘ve been spending long hours on the finishing end on my first blades – which I realize is where most of the time is spent. Being entirely new and having learned everything from reading, I wanted to run my finishing procedures by you folks and see what I can improve.

I ‘ve ground my first blades from O1. I’ve done both flat grinds and hollow grinds. The procedure I used recently for a flat ground blade is as follows: I grind to 220 grit and then heat treat. All the sandpaper in the next steps are silicon –carbide that I use wet. I then sand in the direction of the blade with 220, getting rid of all scratches. Next I move to 320 and sand in both directions, first perpendicular to the blade and then in the direction of the blade. With all sanding steps from here on, I use an Optivisor to get an occasional close look, trying to eliminate all lines. Sandpaper is wrapped around a 1/2" by 3/4" piece of pine. Next I use 400 and 600 EDM stones in the direction of the blade. These are dipped in water. I also use these to detail out some deeper scratches.

Now I do two directions ( first perpendicular and then in the direction of the blade) of sanding with each of the following grits: 600, 800, 1000, 1500 and 2500. Here are the questions: At this point I have a mirror finish with the lightest of (sanding?) lines in the direction of the blade – these can only be seen at a particular angle. Should I or can I do more here? I also don’t have the slightest idea how one uses buffing compound and a wheel. I do know everyone says it is extremely dangerous.

A couple more questions. I don’t necessarily want a mirror finish on every blade I do. How does one do a satin finish? . Also, finishing a flat grind is one thing, but when finishing a hollow ground blade, how do you maintain the very crisp grind lines? I know exceptional control must be part of it, but are there simple devices or holds, etc?

Any help, advice, direction would be appreciated.

Bob
"http://www.southrivermodelworks.com/"
 
Bob, Welcome to shop talk. It sounds like you do spend alot of time wearing out your elbows but should have a fabulous looking blade. Sometimes all the hand sanding will wash out the crisp grind lines. Most of the sanding can be done on the grinder with practise. This is one real reason for the variable speed grinders that are so popular now. They can be turned down so slow that all you have to do is hold your blade against the wheel with fine grits. I have made knives with no hand sanding whatsoever except the handle. You only need the buffer for a mirror shine but must be careefull that you dont contaminate the buff wheel with grinding dust or else it looks worse. If you can get the blade down to 2000 grit by hand then buff, it will only take a few seconds for a mirror. Hope I have helped at all.
 
Bruce -

Thanks for the reply. At the risk of sounding extremely ignorant – how do you use a buffing wheel and compound (what rouge and wher do you apply it)? I like what I am hearing about finishing on the variable speed grinders – of course I want one, but as I learn, I’m seeing what I can do with more modest equip. I have the Multi-tool II with a 1hp Jet for hollow grinding, a 1" x 30" Delta ( I know, but you would be surprised what one can do with it) and an ancient Atlas disc/belt grinder. I’m also thinking of getting a Grizzly 2" x 48". I’ll see where this gets me and then spring for a variable speed at the end of the year. So far, looks good – grinding is a lot of fun even though one has to ruin a lot of metal to learn something.

On belt polishing on a variable speed grinder – I see that (in Texas Knifemakers catalog) you can get grits fine grits from 800 to 2000 . I am assuming that you would use these on slow speeds. Also, any experience with the Scotch-brite belts?

Bob
 
Bob, most handrubbed finishes stop at 600 grit (lengthwise), some go higher some stay below.
On the hollow grind handfinish, get some hard material, about 2-3" long, trace the curve of the wheel used in the grind,grind that curve on your material. You can now wrap your wet and dry paper around it, and you are in business.
You might want to try WD40 as a lube when hand sanding, works well, no rust, just wash the blade well after. Windex also is a great hand sanding lube.
BTW, welcome to the forums, and all the best in your knifemaking endeavors
 
Hi Rade Hawkins has some sheet paper that really helps on hand finishing.
This paper is a manilla color.

Give it a try
It seems to cut very well compaired to wet dry
 
Bob, it sounds like I should take some finishing notes from you! I've never gone beyond 600 grit finish, now I feel lazy.

As to buffing: You can step through the grits on compound the same as abrasive. The TKS catalog does a good job of describing the properties of each. I generally go Gray, White, Pink or Green Chrome. I use the pink for brass or nickel silver, GC for steel. I think there might be a step between gray and white but I haven't figured it out yet.

Use a different wheel for each compound, or at least rake the wheel completely clean between each. I keep wheels and compounds in plastic bags to keep dust from other operations off them. I also use the crocus belts with compound on them, I think this helps maintain grind lines.

I just apply the bar to the moving wheel or belt and build up a pretty heavy coating. It flings everywhere, you'll be glad you're wearing safety glasses and a respirator! Your hair will be full of the stuff.

When buffing on the wheel, be exceptionally careful. The wheel will do everything in its power to grab your knife and fling it into your foot. Buff with your blade at or below the centerline of the wheel so that if it does throw the blade it'll go down and not into your belly. It's really upsetting to have a nearly finished knife bounce off the cement floor, so I've finally put a rug under the buffer. Yes, it seems no matter how careful I am, once in a while one gets away from me. Knocking on wood, so far I'm uninjured.

White compound is no good on dark materials like ebony. You'll want to seal your wood anyway, TKS sells some stuff called Fix It which I like a lot. Fills the pores of the wood and helps keep them from filling with compound. Sand it off completely before buffing.

I can't think of anything to add. You seem to have a great attitude and sound like a natural born knifemaker. Have you done other craft work? Guess I should check out your website.

Dave
 
Another Mass Knifemaker, seems that the #'s of makers in the state keeps growing. You should give jim siska a call and see if you can sweep his shop for knife making tips.
 
I want to thank eveyone for their help & welcome. This is a great forum. I got a lot off all you responses.

-Bruce has me thinking about equipment.

-I tried the WD40 per Mikes suggestion and it does help considerably. It also works great with EDM stones. Next - Windex

-Darryl, I'm going to get some of that paper.

-Dave - thanks for the great explanation of buffing. It scares the dickens out of me. I already have a shop full of potentially dangerous tools .. also, thanks for the compliment & very perceptive of you... I've done craft work in several areas over the last few decades.

-Striper - I've met Jim at a couple shows. Heck of a nice guy and like everyone else, very generous with knowledge..though if you looked at my shop, you might question if I know which end of a broom to use.

Bob

http://www.southrivermodelworks.com/
 
Nothing to add, Bob, just wanted to say welcome! Enjoyed my visit to your website. Some very beautiful work there.:)
 
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