help me with my stones

S

stonemedusa6264

Joined
Mar 3, 2022
Messages
360
I'm looking to have the stones for reprofile through mirror polish. When my next order come in I'll have:

Venev centaur F80-150 dual sided(on order)
Venev kit I got when I got the system. All dual sided. F100-F240 100%, F400-F800 25%, F1200-F2000 25%
Have one that's the same series as that kit in F1200-F2000 100%. There was a note on this and the 2000 25% in the kit that they were experimental and might leave scratches.
Paltava cbn 8000(on order), 15k, and 30k. It was a challange to find the 30k. If i understand the scale right its less than .5 micron.

So the F100 takes forever to reprofile or get chips out. Hopefully the 80 is a little better and the same thickness as my other dual sided stones. On the other side it doesn't seem to matter what order of finishing stones I use. I still notice scratches I think are from the 800 or earlier. I've went through the 25%1200 finished with the 15k n 30k, n bounced back n forth using the 1200-2000 100% n 25% not using the 2000 using the 2000 finishing with the cbns again. The last stage of diamond stones doesn't seem to matter. It might get a little a better but it still seems like I'm missing something further down. I also have some fine micron films that I haven't pulled out since I got the 15 n 30k cbns.

All the stones have a fractional number on them if that'll make it easier for someone to tell if I'm missing a grit. Might be going overboard here. I can get a nice mirror edge, it'll whittle hairs without a strop.
 
I have run into the same thing: low-grit diamond stones are slower than, say, AlOx stones of the same grit, and they tend to leave some rogue deep scratches, a problem that gets much much worse if you increase pressure to try to increase speed.

They're great for polishing to a mirror at higher grits, and pretty good at the low grits at low pressures if you are not a mirror perfectionist, but I'd be thinking about something besides diamond in the low grits, if you are after a truly clean mirror finish. The other choice is to just keep at it with the high grits until you get the scratches out, using light pressure and letting the stone do the work.
 
If I'm adjusting the angle or getting chips out I might press a little on the 100. Besides for that I never use pressure more than the weight of the stone. If I'm going for fix n polish I'll get a slight bur down both sides with no pressure and a few rounds down both sides no bur so the steel isn't scratching itself coming off a bur.

I guess I forgot I use water and soap, clean regularly. I normally use a vice system with an adapter for a convex edge and that makes the scratches worse in the center but better on the edges. The cbns polish everything they hit so maybe I'll work my way down the grit chart with them. I stuck with diamond and cbn so I could do super steels. The hardest sounding/feeling knife I put a mirror on so far was a kabar wrench knife I've never used. So I'd rethink needing them.

I also haven't lapped the original kit in a while. I could do that again.

What stones would you change for what stones?
 
The supersteels make it tricky. Given that, I'd probably stay with the stones you have, but never use heavy pressure, and still expect some rogue deep scratches from time to time, but not as deep as if pressure were used.

Although it is tempting to see whether some non-diamond stone would work well in the early stages, trusting the later diamond/CBN stages to deal with cleaning up the carbides. Haven't tried that with supersteels, so I don't know whether it works.

Some things that people like as coarse stones: Norton Crystolon/India (cheap), Baronyx Mutt (cheap), Shapton Glass 500 (not cheap, but widely adored; I use mine a lot and its scratches are very consistent and manageable). For super-coarse, there is the Baronyx Manticore, if you need a real steel-eater, which I hope you don't.
 
stonemedusa6264 said:
What stones would you change for what stones?
Click to expand...
A Poltava CBN 120 (metallic bond) stone would serve you much better than getting a Venev centaur F80-150 when you already have the Venev F100-F240. The Venev F80 won't make much difference compared to the F100 when it comes to cutting speed.

The Poltava CBN 120 is a great & fast bevel setter and cuts uniformly and evenly.

And yes, you are correct - the Venev F2000 is experimental and some of them suffers from diamond agglomeration which causes them to create some stray deeper scratches.
 
I figured the 80 wouldn't be much faster. F80 to 150 to 240 instead of F100 to 240. 70 n 90 intervals instead of 140. The 100 produces more slurry and I tend to use it a lot more if I have to fix an edge so I was also thinking I might wear it out faster than others.

I only have experience with the finer CBNs. I could add the 120CBN. Have you ever seen the 60CBN available or used it?

The 1000 n 400 CBN also line up in their chart as being between grits I have. They look like they'd be around F550 n F320. Not sure if they would be worth getting to split the F240 to 400 and 400 to 800 gap?

I assumed the chart was accurately laid out on the micron scale. The more I look at it I'm not sure. Looks like that scale could be a little off.

I lapped the stones when I got them and I've never noticed scratches that I could say were definitely coming from F1200-2000s. Even the 100% concentration ones don't seem to leave anything deep. It'll create a little more of a blurry mirror than the 25%. Which kinda checks out to more little scratches. The 8k cbn is about the same as the F2000 so I should be able to double check that.

I've also been worried about something I don't think matters. I've only had to adjust height in the higher grits when I've used lower grits to see rough spots. The furthest I've got is the 15k n jumped back down. I can jump from any stone to any stone as long as I use those two to adjust my height?
 
stonemedusa6264 said:
I only have experience with the finer CBNs. I could add the 120CBN. Have you ever seen the 60CBN available or used it?
Click to expand...

The 120 CBN seems to be a happy medium with good cutting speed without excessive edge chipping when you apex the edge. Coarser is slightly faster but causes more edge chipping, which then takes longer to remove.
 
Last edited:
You must log in or register to reply here.
Back
Top