7 Profiled Blades, but poor sanding

[medit8]

If I did this right, I am attaching a picture of the 7 blades that I have recently done stock removal on. My boss (wife) has made me promise not to try heat treating in the house just yet, so I'll be sending them out for that. I believe that I will have to sand them down again after I get them back, but I have run into a problem with sanding on all of them. Just using a belt sander, I have been unable to get the centers of the blades to a mirror finish. So, my question is if I should do hand sanding now or wait until I get them back after heat treating. My second question is if there is some way to get a nice overall no-scratch appearance with just the belt sander. The edges of the blades come out real good, and I'd like to be able to get that all over. My fingers and hands are a bit arthritic, so I'm not looking forward to doing much hand sanding.
Thanks,
Bob

[dudeinthehut]

Well, I haven't made that many knives, but I too find grinding and polishing the flats too be more difficult.

I only use my wimpy belt grinder and go through the following grits: 60 (for hogging), 100, 220, Heat treat, 220 again, 320, 400, 600. Everything after the HT is does very slowly with a bucket of water and a spray bottle close by. I dip the blade after every pass or I wind up turning the tip blue. I suppose I could go finer before HT but I don't ever want to face a warpage problem on a thin, final-ground edge. Note: I have only used W-2 file steel so far for my blades.

After the 600, I use a medium buff wheel and the green tube of compound they sell at Lowe's. Then I go to a soft buff wheel and the red tube of compound (also from Lowe's) for a pretty decent mirror finish. I do no hand sanding at all.

Have fun.
Andy

[Jason Cutter]

Unfortunately, I think it boils down to experience. It is very difficult to get a good mirror finish - period. Even a high grit finish that is near mirror polished is hard enough. Regardless, unless you are very accomplished with the grinder, you won't be able to achieve the PRE-BUFFING degree of finish without first doing some hard work by hand.

Many knifemakers also like a simple satin finish that you get straight off the grinder. That way you don't need to do any hand sanding. However, to pull it off, your grinds need to be very clean and crisp. Check out Bob Dozier's workhorse knives. Once again, it boils down to experience and you also need to be fairly accomplished at the grinder. For this reason, many makers simply do some hand sanding on all their blades to achieve the look they prefer.

The concept is that a grinder is faster, but it also makes mistakes faster. And a buffer is the most dangerous machine in the shop, so you want to spend the least amount of time in front of it.

After a few years of making knives, my own method is to hog the bevels out with 50grit and 80grit, then 120 grit, and MAYBE a 240grit belt. Everything else is done by hand. Some blades are taken up through 240, 400, 600, 800, 1200, 1500, 2000, 2500grits in less than 45minutes of hand sanding. At that point, I have the luxury of options. I can either leave it a very fine satin finish, or go to the buffer to get a mirror polish.

Hope I haven't discouraged you too much, just stating the facts of life. I've tried to look for a short cut myself (over and over), and haven't found one. Not yet anyway. Jason.

[medit8]

Thanks Jason and Andy,
I've learned alot from your replies and appreciate them greatly. I think I'm going to follow both of your methods, gain the much needed experience, and be glad if I can get a scratch-free or satin finish, let alone a mirror one. I've had quite a hard time getting the center areas scratch free, and for now if I can achieve that, it'll be plenty satisfying. I'll be sending them off in the next day or 2 for heat treating and will post pics of some the finished knives when that happens.
Thanks again,
Bob

[TOM BUCHANAN]

can't add much to whats benn posted here,but bruce evans had a posting where he used a small palm sander.if the hands bother you, that may help.on some working knives, i hit 'em with 220, 400, and a scotch-brite wheel.good luck.

[markd]

I don't know what type of grinder you are using, but it looks similar to probs I had. You may have the convex grind blues. When putting pressure on the belt and not using a platen, the belt will conforn to the edges of the blade, but there is a little gap in the center where the belt is not actually touching the blade.
Are your edges rounding and the center not getting ground?

Been there, try flat grinding by putting blade pressure against the platen and not a more slack part of the belt.

[medit8]

Yo Markd,
Thanks for the great tip! I had previously purposely been grinding the blades mostly on the looser parts of the belt, as I didn't understand about the belt conforming to the edges and not hitting the center. I tried putting a test blade over the planten, and it does appear to be doing the trick. I'm anxious to get the heat treated blades back to see how it goes. Thanks again!
Bob

[dudeinthehut]

Bob,

Just remember to go real slow and easy when grinding after a heat treat. You don't want to heat anything up after HT. I use a spray bottle and a dunking pail.

I still always manage to blue the tip when final grinding after HT. Then I have to slowly grind the tip down past the blue area to return to hard steel. I'm still learning too!

Have fun!

Andy

[markd]

Originally Posted by medit8

Yo Markd,
Thanks for the great tip! I had previously purposely been grinding the blades mostly on the looser parts of the belt, as I didn't understand about the belt conforming to the edges and not hitting the center. I tried putting a test blade over the planten, and it does appear to be doing the trick. I'm anxious to get the heat treated blades back to see how it goes. Thanks again!
Bob

Things go slightly better when someone else makes mistakes for you.

[medit8]

Yo Andy,
Thanks for the warning about going slow and taking it easy to prevent heat. I will be careful. As far as having fun, I've really enjoyed every aspect of knife-making so far, and maybe too much so - I'm definitely addicted!
Yo Markd,
I hope you won't mind my plagerizing your excellent quote:
"Things go slightly better when someone else makes mistakes for you"
And I think it really demonstrates why the Newbies forum is so valuable. There seems to always be someone who has been there and done that, and is considerate enough to share their hard-gotten knowledge. Thanks!
Bob

[markd]

No prob, man. I have "allowed" Tracy Mickley to make some mistakes for me. Least I can do is pay it forward.