Fingerstones - My Method

[Smurfmacaw]

Some folks have asked how exactly I thin down the stones and what tissue etc. Thought I'd throw together a quick set of pics on the process.

Tools and equipment

5 Minute Epoxy - I use West Systems because it's what I have. I use 5 minute epoxy because it's more flexible than the slower set epoxy due to the fillers in it to make the mixture 1 to 1. (Normal West 105 uses a 4:1 resin to harder mix and its much harder and may cause the tissue to break when you fracture the stone.)

Raw finger stones - I got mine from Jon at JKI. These are the harder stones of the two types he sells.

Not pictured is a 220 Gesshin stone. Makes the job easier. About twice as fast as a 500 grit (surprise lol). Needs to be flat or it's hard to keep the fingerstone flat.

Calipers - you can eyeball it but I have calipers so I use them. Grind a little measure - wash, rinse, repeat.

Selection of stones - once close to final dimension then get finer and finer on the grit. Finish with natural stones.

Tissue - Jon sends the proper tissue with his finger stones. This is very thick tissue, almost like Tyvek.

Also will need gloves for the epoxy. There are those who are sensitive to uncured epoxy and those who will become so. I use epoxy a lot so I'm careful even though it doesn't affect me. I build silly things like this - https://www.youtube.com/watch?v=OKsZi8ddDHw...and you thought knives were expensive!

 

[Smurfmacaw]

And of course, no job can occur without a quality control supervisor....She intently observes the entire process to ensure I am safe and doing it properly.:cool2:

 

[Smurfmacaw]

After everything is laid out the process begins. The stones from Jon come pretty thin...maybe 3.5mm and flat on one side and slightly rough on the other. They are not, however, of uniform thickness. I grind on the rough side until they are the same thickness. It's kind of like grinding a bevel, it all depends on where you put pressure with your fingers.

 

[Smurfmacaw]

While grinding I've found a constant stream of water on the synthetic stones seems to work best. Once of uniform thickness, I try to vary pressure over the stone while grinding and rotate it very often to grind evenly. I ground a number of telescope mirrors when I was an undergrad many years ago and it's the same thing. By rotating often, all the little errors average out and it stays relatively flat. I'm aiming for 1mm at this point. It takes about 10 minutes at most once you get the hang of it. Measure often! I figure i'm within a hundredth of a mm so that's good enough.

 

[Smurfmacaw]

Next is to dry the stones and cut a piece of tissue slightly larger than the stone. Gloves on, mix the epoxy and then coat the back of the stone (pick the worst side but at this point they should be pretty much the same) and put them on a piece of parchment paper (you have parchment paper don't you??) The silicone in the parchment won't stick to the stones. Then I push the tissue down to make sure it's saturated with epoxy, cover with another piece of parchment and weight with something flat (Like shapton glass stones...the back is perfect). I let it cure for about an hour at least before proceeding. I'll pick this back up once it cures.

 

[mikedtran]

Great writeup!!

I currently use a Atoma 400 Diamond Plate to do the flattening, would a King 6000 be ok for the final flattening?

 

[aboynamedsuita]

I'll pick this back up once it cures.

So much for 5 min epoxy lol :groucho:

I'll probably use the West System G/Flex for mine as my only other option on hand is devcon 2 ton which "shatters" once cured.

This thread will be interesting to follow just like the previous one (http://www.kitchenknifeforums.com/showthread.php/24469-My-Foray-Into-Finger-Stones). Thanks for doing it.

 

[ynot1985]

Thanks for the write-up... this was very informative (need to bookmark this page)... can't wait for part 2 .

btw, are all those cages for just one bird? it doesn't look like a macaw so what kind of parrot is it?

 

[icanhaschzbrgr]

May I ask why would one want to make fingerstones of even thickness? Seems like a waste of time to me, thought I confess I have very little experience with them. The ones I use are 2-3 times smaller and basically are just chunks of stone. I flatten one side and left the rest as is… seems to work fine for me.

 

[Smurfmacaw]

May I ask why would one want to make fingerstones of even thickness? Seems like a waste of time to me, thought I confess I have very little experience with them. The ones I use are 2-3 times smaller and basically are just chunks of stone. I flatten one side and left the rest as is… seems to work fine for me.

Each of these stones is enough to make 6 to 9 actual fingerstones. I'll finish them today and show why you want them thin and even. Got side tracked with the block party my neighborhood has every year to celebrate the christmas lights.

 

[Smurfmacaw]

Thanks for the write-up... this was very informative (need to bookmark this page)... can't wait for part 2 .

btw, are all those cages for just one bird? it doesn't look like a macaw so what kind of parrot is it?

We have a total of five parrots. This one is a female eclectus parrot. They are the only parrot species that you can tell what sex they are visually....the male is electric green with a beak that looks like candy corn.

 

[Asteger]

About having even thinness, I think if it's irregular then, after you've glued the stone to the paper, when you score and break the stone up in the little grid (so that it flexes), the breaking (against a spoon, etc) might not work out and you'll have thicker pieces or some crumbling and so on. I think, though, that it's a concern and you'll need more flexible stones that have had the careful prep for certain knives more than others. The face on 1-bevels above the shinogi or on some shinogi-sporting 2-bevels can be pretty flat, and so I'd not spend less time on prepping a stone for these.

 

[Smurfmacaw]

I've found that not very many single bevel knives are really flat until you get into higher dollar knives like shigs or Haburns. I've got a suisen single bevel and it is not even close to flat (and it was VERY difficult to get it flat....hardest steel to grind I've had). With a flexible stone you can make a knife that isn't really flat look good since it follows the contours pretty well.

 

[ynot1985]

We have a total of five parrots. This one is a female eclectus parrot. They are the only parrot species that you can tell what sex they are visually....the male is electric green with a beak that looks like candy corn.

I thought knives were expensive until I looked up how much each of these go for here and this is meant to be a native bird

 

[Smurfmacaw]

I thought knives were expensive until I looked up how much each of these go for here and this is meant to be a native bird

Haha, look up the hyacinth macaw. Then the cage costs that much again. But, they live 80 years so I guess it's not so bad when you amortize it out. Galah's go for $2000 here and I think you guys pretty much consider them pests.

 

[ynot1985]

Haha, look up the hyacinth macaw. Then the cage costs that much again. But, they live 80 years so I guess it's not so bad when you amortize it out. Galah's go for $2000 here and I think you guys pretty much consider them pests.

ah I have seen those in the HK bird market before... now that's a BIG bird

 

[Smurfmacaw]

Yeah, he's a big boy. His beak is intimidating (consider he can open macadamia nuts in the shell) but he's pretty gentle for the most part with it. He does like to roughhouse a lot - kind of like having a puppy with a bolt cutter on his face.

I'll try to get the stones finished tomorrow, things just didn't lend themselves to finishing them today. I think seeing them scored and made ready to use will answer a lot of questions.

 

[ynot1985]

Yeah, he's a big boy. His beak is intimidating (consider he can open macadamia nuts in the shell) but he's pretty gentle for the most part with it. He does like to roughhouse a lot - kind of like having a puppy with a bolt cutter on his face.

I'll try to get the stones finished tomorrow, things just didn't lend themselves to finishing them today. I think seeing them scored and made ready to use will answer a lot of questions.

Oic.. now I get where you got your name from now....

back to stones... correct me if i'm wrong but if were to buy fingerstones, the size of the stones are way more important that the overall thickness of the stones itself as the overall aim is to thin it to 1mm anyway?

Am I wrong to make this assumption? the reason I ask because some place sell thick pieces of Urchi and call this fingerstone and this wouldn't not be ideal then as you would need to thin that down anyway

 

[inzite]

haha very cute bird right there and that's alot of cages! looking forward to part 2!

 

[Smurfmacaw]

Oic.. now I get where you got your name from now....

back to stones... correct me if i'm wrong but if were to buy fingerstones, the size of the stones are way more important that the overall thickness of the stones itself as the overall aim is to thin it to 1mm anyway?

Am I wrong to make this assumption? the reason I ask because some place sell thick pieces of Urchi and call this fingerstone and this wouldn't not be ideal then as you would need to thin that down anyway

I'd say the area of the stone is more important. If you have perfectly flat wide bevels you can use a thick solid stone but it is still harder than using a flexible stone. I thin them to 1mm before I glue on the tissue and then thin the stone to .5mm in the final steps....have to be careful to measure the thickness the epoxy and tissue adds though. I've found the tissue adds about .35mm or so. Will get to work tomorrow and hopefully finish the stones.

and a little about Indigo http://www.kitchenknifeforums.com/s...nd-online-name?p=387118&viewfull=1#post387118