Coticule Flattening - How Often

[Matt]

Hey, folks!

Today, just after leaving the toilet (you know that many good ideas come to the uncluttered, unoccupied ...mind... : ) I had a brilliant idea. Thinking about my two Cotis that would arrive any moment (actually they're here already! :w00t: :w00t: ), I had an idea that, if someone was in desperate need of lapping his stone, it could be done with another Coti, just before honing, instead of rubbing it with a slurry stone. This way you kill three birds with one (actually, two) hone(s) - primo, you get both hones lapped, secundo, you get slurry, and tertio - you save you slurry stones! Plus, since they will be worn in the middle, so both will be in contact in areas where it is needed the most.

Ain't that worth a try? Sure, probably makes sense only with moderately worn hones, but we shouldn't allow severely banana shaped hones, like tat's, should we?

 

[StraightRazorDave]

Hey, folks!

Today, just after leaving the toilet (you know that many good ideas come to the uncluttered, unoccupied ...mind... : ) I had a brilliant idea. Thinking about my two Cotis that would arrive any moment (actually they're here already! :w00t: :w00t: ), I had an idea that, if someone was in desperate need of lapping his stone, it could be done with another Coti, just before honing, instead of rubbing it with a slurry stone. This way you kill three birds with one (actually, two) hone(s) - primo, you get both hones lapped, secundo, you get slurry, and tertio - you save you slurry stones! Plus, since they will be worn in the middle, so both will be in contact in areas where it is needed the most.

Ain't that worth a try? Sure, probably makes sense only with moderately worn hones, but we shouldn't allow severely banana shaped hones, like tat's, should we?

That is something worth a try, but my worry is that both hones would lap together, but not necessary both be flat. I've heard of instances (somewhere over at SRP...) that when you lap a stone with another stone both stone might end up complimenting each other in terms of there warpage (yes, "warpage" is a word now ), i.e. if one stone is convex and bows out in the middle the other stone you lap with it might end up concave so they both fit together. I hope I explained what makes sense in my head....

But as far as raising a slurry goes, using another coti should work just as well as a little slurry stone, but it just might be a little more cumbersome.

 

[PA23-250]

As far as DMTs getting worn out by lapping coticules, I read a great explanation for that on SRP about a week ago. As you probably all know, the diamonds are held in place by a thin layer of nickel. Those garnets that cut metal so well are pretty indiscriminate... Particularly on the finer plates (600 & up), the garnets will actually eat away @ the nickel holding the diamonds in place, and before long, it's goodbye.

Now I've quit raising slurry from anywhere but the ends or corners to minimize the need.

 

[justin]

I think the original advice is the best for this.

*flip the stone between slurry
I find that if I don't flip the stone there is uneven wear. Flipping it reflects the wear, helping to even it out.

*rubbing the ends to counter dishing.

*rubbing any high spots that you notice.

*another thing that I do is if I notice a high side I'll flip the stone accordingly and use the high area.

I have a suspicion that a narrower stone is easy to keep flat.

 

[Bart]

As far as DMTs getting worn out by lapping coticules, I read a great explanation for that on SRP about a week ago. As you probably all know, the diamonds are held in place by a thin layer of nickel. Those garnets that cut metal so well are pretty indiscriminate... Particularly on the finer plates (600 & up), the garnets will actually eat away @ the nickel holding the diamonds in place, and before long, it's goodbye.

Now I've quit raising slurry from anywhere but the ends or corners to minimize the need.

Thanks for posting that. If I may add something?
I can tell you out of first hand experience, that DMT's are very good hones, but the diamonds do wear down. I have worn out a DMT-325 by lapping slabs of raw Coticule (slices cut by a diamond stone saw). The DMT shows no significant loss of diamonds. They just lost their bite. A friend that was helping out with lapping the Coticule samples, accidentally used the 600 grit side of the DMT (it's a double sided DMT E/F). After about 15 minutes of vigorous lapping, we noticed the mistake. The hone kept it's particles, but also in this case the speed loss was very significant.

I'm not saying it's impossible to knock diamonds out of the nickel matrix. I just want to add that the diamonds do wear.

Best regards,
Bart.