mirror polishing 440-C

A

aerostar

Joined
Oct 26, 2001
Messages
203
What is the recommended procedure to start with a profiled, heat treated 440-C blank and wind up with a mirror polished blade?
Pre polish before heat treat?
Buffer hp ratings, wheel sizes, rouge colors, etc. Any advice would be greatly appreciated. Thanks in advance.
 
aerostar,

The only method I know of is the lebow grease and buff :) Start with wet and dry sandpaper at a grit matching the finish your heat treated blade is at. If this is a blade from a knife supply house, I am guessing you could start at 220 grit. WUse the following progression:

220, 320, 400, 600, 800, 1000

The higher you go, the better. But I think 1000 is a good place to stop and try out a buffing. I have 2 compounds for buffing. One is a green compound that I think is around 1200 grit. It will remove the very fine 1000 grit scratches and make the blade shine. Then I use this white compound that is specifically made to be used after the green stuff as a final step. It really makes the blade shine then. I just use 5" wheels on my drill press!!! That's all I have for equipment, so I do what I can to make it work. With the sandpaper, change the angle you sand at each time. That way, when the old sanding lines are gone, you know you are done with that grit. And use a sanding block too. If you just use your fingers, the sand paper will follow the dips and bumps instead of leveling things off.

I haven't been too lucky at machine finishing, so I can't help you out there. Good luck!
 
Aerostar, if you get a buffer please be super careful and if the blade you're finishing is already sharp, knock the edge off it before working it. The buffer is the most dangerous tool in the shop and will bite you with a vengance! Never get near the top edge of the blade you're buffing. You need to do 99% of the work before going to the buffer and then just spend a few minutes on it with very light pressure. You can easily ruin a blade by over buffing.
 
I would start at 400 and use some rouge, but first make sure the edge is gone! or pray you dont hurt yourself!! that edge catches on a buffing wheel you could get hurt bad!!! so be careful!!!!
 
Aerostar,
The procedure I use and seems to work very well is this sequence: After heat treat, 50, 120, 220, 400, A30,A16 then A6. This will give you a mirror polish. The buffer will only brighten up the finish. Buff (very little) with green, pink (no scratch) and finish up with white. Buffers are the most dangerous thing in your shop, be careful. Try not to "wash out" your grind lines. Good luck, Mark
 
...gee... does anybody want to polish a bunch of blades...?
You guys are great! No kiddin'. Thanks everybody.
Yeah, I don't want to wind up looking like Gumby wound around the buffer.
 
As Mr. Cooper mentioned, be careful not to overheat the blade on that buffer. 440-c has a fairly low tempering temperature and you can easily ruin the heat treat on the blade by overzealous buffing.

Some really sage advice from everyone here. That's so cool.:cool:

Best of luck in your endeavour,
Mike U.
 
All above advice is excellent. I also use a flat surface for the flats and if it is hollow ground I use the same wheel to do the hand sanding. It can be removed or left on the machine, whichever is more comfortable. It has the right radious and is hard enough rubber to do a nice job to not sand away the crisp grind lines.
 
when you grind, it's blade edge up! when you buff, its blade edge down. happy grinding!
 
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