Tumbling Blades

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Fiddleback

Knifemaker
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Can you guys educate me about tumblers, and finishing blades in a tumbler. I love the look, but looking at machines on the net is very confusing.

What size is necessary?

What media?

What are you taking the blade to before tumbling?

How long does it take?
 
Here is a link to a blade that i recently tumbled

http://www.bladeforums.com/forums/showthread.php?t=828406

I used one that i purchased from Northern tools (the link is in the thread). I used 3/8 inch 22 degree cut ceramic media.

I finished the blade to 400 grit. I found that the tumbled finish highlights flaws.

I got the finish on that knife in about 20 minutes in the tumbler, the steel is ATS34 measured at 59 RC.

I tried several smaller tumblers without much luck.

Hope this helps.

-John
 
AcridSaint said:
John - are you running the tumbler wet or dry?
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Excellent question. I should have talked about that in the thread.

I found that if you run it dry, the media loads up very quickly and starts to polish rather than cut. Ideally you would want to have a stream of cleaner in the tumbler during operation, but i found that by adding a few cups to it every 5 minutes or so worked fine. My tumbler has a drain in the bottom that just goes to a 5 gallon bucket. I use an industrial cleaner called "VF-100" that mixes with water.
 
It takes a relatively powerful vibratory tumbler to achieve the frosty looking stone wash finish, otherwise it just polishes it a little and leaves a somewhat mat finish.

I use heavy pointy aluminum oxide media that is designed to cut for heavy burr removal. This will remove 400 grit grinding marks in a couple hours, but any hidden 220 grit marks will still be there and will become obvious. The process rounds off corners and edges, so if you're one who likes very crisp hard grind lines you're not going to like this process very much. But if you like smoothly blended corners and edges you'll like it.

I do it wet, I use old coolant from my sumps as my fluid. They sell soaps for this process, but I've never tried them. You have to keep your fluid fresh or the process stops cutting and starts burnishing.

Blades tend to find each other and stick to each other. They're "self assembling". So I run a screw through the tang to create a bump so they can't stick together.

On one occasion I had too many blades in at the same time and they formed a log jam. After being clumped together and rubbing each other in the same spots for a hour they formed gouges and divots in each other, so I had to scrap that lot. Now I only do a few at a time, though my tumbler isn't very large.

Big industrial tumblers are noisy and messy, so I stuck it in a building at the back of my property rather than put it in my workshop.
 
Would beadblasting give you a similar finish? It'd be faster and less messy for sure. Also you can "mask" corners in stages to maintain a semblence of sharper corners if you're carefull.
 
crex said:
Would beadblasting give you a similar finish? It'd be faster and less messy for sure. Also you can "mask" corners in stages to maintain a semblence of sharper corners if you're carefull.
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Maybe. And as this thread has progressed I'm thinking harder about it. The problem is that 01 steel is going to rust fast if blasted.
 
johnnym said:
Here is a link to a blade that i recently tumbled

http://www.bladeforums.com/forums/showthread.php?t=828406

I used one that i purchased from Northern tools (the link is in the thread). I used 3/8 inch 22 degree cut ceramic media.

I finished the blade to 400 grit. I found that the tumbled finish highlights flaws.

I got the finish on that knife in about 20 minutes in the tumbler, the steel is ATS34 measured at 59 RC.

I tried several smaller tumblers without much luck.

Hope this helps.

-John
Click to expand...


I could be wrong but I think that 20 mins in the tumbler is just enough to scuff it up and not finish the satin look. I would try 2 hours. I know that when we tumble finish hilt parts that we leave it in for much longer the 20 mins.
 
O1 is going to develope an oxidized patina of some form anyway you go unless you keep it coated with something. Soon as you chop the first green bush or dress the first deer.... it's going to age like it's supposed to. I like it because it does just that (besides holding a terrific edge).
 
Matthew Stagmer said:
I could be wrong but I think that 20 mins in the tumbler is just enough to scuff it up and not finish the satin look. I would try 2 hours. I know that when we tumble finish hilt parts that we leave it in for much longer the 20 mins.
Click to expand...

You can see from the thread that i linked, the finish that i get in 20 minutes, I have left it in longer but the finish does not change much. I think that the time that it takes is based on several factors,

1) how aggressive the media is. You can purchase ceramic media based on cutting aggressiveness. Here is a good link to look at.

http://www.rhodesmktg.com/products/ceramicmedia/ceramicmedia.html

2) how new the media is. The media eventually wears and needs to be replaced.

3) How powerful the tumbler is. A larger tumbler that holds 100 lbs of media will cut faster than a smaller one.

I suspect that as the media in my tumbler gets older, it will take longer to get the finish that i am looking for.

-John
 
Grit blasting is quite different than stone washing. Grit blasting shows new scratches readily and also creates noticeable drag when cutting certain things. It is, in essence, lots of small craters.

Stone washing is, in essence, lots of fine scratches. It is a brighter smoother finish than grit blast, and it also hides scratches better, so it wears better.

In my opinion, other than both being non directional "satin" finishes, the two finish types are quite different.
 
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