EDM Stone Guidance

ChristoDart

ChristoDart

Joined
Jun 29, 2011
Messages
750
Good evening all. I’ve been wanting to get into using EDM stones for an initial hand sanding finish but have been intimated by where and what type to order for awhile. I know they’re widely used in the forum but the exact type isn’t normally mentioned. I’ve done research but then eventually give up because of different sizes and softnesses of the stones. Our commonly used knife supply stores also don’t carry them. Can anyone point me in the direction of a good first order like we do with belt progression and type? Thanks!
 
Wow, I've regrinded, and polished knives before I had even thought about making knives, and I had never seen these before. I bet this would seriously save me some money on sandpaper, especially doing very fine polishes.

Obviously I can't give any advice on them, but thanks for posting this!
 
McMaster Carr has them, just search for "EDM polishing stones" on their website. I use them mainly for plunge line scratch removal/finishing. I don't use them for the entire blade as most of my knives have a little convexity to them. I start with 120 grit then 220 then 400. Then I go to sanding paper for the entire blade.
 
I use Congress Tool.
EDM1201126 for example.
That is a 120 grit, 1"x1/2"x6".
I also like the 220 and 320 grit.

ETA: Nathan the machinist has posted several times that he likes N grade diemaker stones from Falcon.
 
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I like the ones from Gesswein. I use EDM for 100 - 220 grit. Then Mold Maker Plus 220 - 400 grit and then 600 with mold maker. Different stones have different hardness and breakdown levels. I've cut down a ton on the amount of sand paper I use.
 
Per Nathan's recommendation, I use the N grade from Falcon. I LOVE them. They work great for removing the machine finish when going to hand rubbed. They are so much faster than paper. I finish with Rynowet, but start with 220 grit N grade stones.
 
Thank you all for the replies. I ordered some 120,220, and 320 from McMaster Carr. I wanted to get the Falcon N’s but could only find them in a min order of 12 at a time.
 
Stuart Davenport Knives said:
Per Nathan's recommendation, I use the N grade from Falcon. I LOVE them. They work great for removing the machine finish when going to hand rubbed. They are so much faster than paper. I finish with Rynowet, but start with 220 grit N grade stones.
Click to expand...
What grit do you typically come off of on a machine finish?
 
I learned about these die makers stones from Billy Mace Imel.


An advantage of a stone over a paper is you do not round over features, it remains crisp. And it doesn't go dull or glaze, it just continues to erode.

Remember, it is the slurry that grinds as much as the stone. Build up your slurry and it cuts quickly.

They sell a solution that works really well with the stones but WD-40 works in a pinch.
 
Stuart Davenport Knives said:
Per Nathan's recommendation, I use the N grade from Falcon. I LOVE them. They work great for removing the machine finish when going to hand rubbed. They are so much faster than paper. I finish with Rynowet, but start with 220 grit N grade stones.
Click to expand...
I do the same. I use 320,400 and 600 most often. They sometimes sell kits which come with the stoning oil and those are very economical.
 
Gosh this is interesting... may need to try some of these out!

1.) Do yall have to periodically flatten these stones with a DMT lapping plate?
2.) Do yall ride the edge of the stone up the radius of the plunge? Maybe radius the edge of the stones some?
 
J. Keeton said:
Gosh this is interesting... may need to try some of these out!

1.) Do yall have to periodically flatten these stones with a DMT lapping plate?
2.) Do yall ride the edge of the stone up the radius of the plunge? Maybe radius the edge of the stones some?
Click to expand...
The ones I buy are $5 each so I use them until they are too far gone and grab another. I buy 6 of each grit.
I use them in a variety of ways. I especially like them for polishing a sharpened clip or spine. I can convex the edge also. I don't usually use them on the plunge. I do use them on the tang-ricasso junction if the guard isn't fitting perfectly and the blade is already hard.
 
J. Keeton said:
Gosh this is interesting... may need to try some of these out!

1.) Do yall have to periodically flatten these stones with a DMT lapping plate?
2.) Do yall ride the edge of the stone up the radius of the plunge? Maybe radius the edge of the stones some?
Click to expand...
You don't really use the "flat" of the stones, but the ends of the stones, almost like a chisel. They wear relatively quickly, which is good, since you always have fresh grit to polish with (most the reason that these work so much faster than paper). Because they wear so fast, however, you wouldn't get very far if you tried to put pressure on the flats, as you'd just end up breaking or wearing your stone out faster.

That said, they do make thicker stones, if you want to use a little more surface area of the stone end, though I normally just use stones that are around 1/8" thick by about 1/2" wide or so, IIRC.
 
I like the diestar stones from Congress tool. I found the others to be so hard they gouge easily.

I just got a DMT extra course diamond stone in the mail today. I didn't expect much, but it does a surprisingly good job at flattening the bevels without disturbing the flats. Cuts quickly too. I'm not sure how long it'll last.
 
I would also like to know what everyone’s using as a ‘lube’. I just got mine in and used some krud cutter because that’s what my DMT stone instructions suggested and it seemed to work fine but didn’t make a great slurry.
 
ChristoDart said:
I would also like to know what everyone’s using as a ‘lube’. I just got mine in and used some krud cutter because that’s what my DMT stone instructions suggested and it seemed to work fine but didn’t make a great slurry.
Click to expand...
I use the Supreme Green Stoning Oil from Gesswein. Works better than WD40 or honing oil or anything else I tried. Bought a gallon and put it in a squeeze bottle.
 
J. Keeton said:
Gosh this is interesting... may need to try some of these out!

1.) Do yall have to periodically flatten these stones with a DMT lapping plate?
2.) Do yall ride the edge of the stone up the radius of the plunge? Maybe radius the edge of the stones some?
Click to expand...
I don't flatten the stones. As they wear down you can adjust the angle and get a nice end that works awesome with the plunge line.
 
J. Keeton said:
Gosh this is interesting... may need to try some of these out!

1.) Do yall have to periodically flatten these stones with a DMT lapping plate?
2.) Do yall ride the edge of the stone up the radius of the plunge? Maybe radius the edge of the stones some?
Click to expand...
If you start using these, I love it if you put a video out detailing your findings.
 
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