Les Lat...is this crack going to be a problem?

[algebro]

Hey all,

I picked up a les lat from eBay and did not notice that there was a crack in the original pictures in the listing. I've never honed on a coti but I wanted to check if the crack will mess up the edge or if I need to try to avoid it with the blade while honing on it. I mostly can't feel it with my fingers but there is one spot in the middle of the line that does feel slightly rough. Do you all have any tips for me? Thanks!

 

[Jens]

Why don't you try it, and judge by the result. If you are careful lapping the rock before proceeding, my guess is you'd be fine ...

 

[Wid]

Lap it and see. If you turn the stone 180° and start on that side chances are you’re not going to be near that price to begin with.

 

[Eshebert]

If you cant feel it with nail or blade your good. If not, lap it flat and it will be.

 

[algebro]

Sounds good, thanks for the advice all. So it sounds like cracks aren't much of a problem as long as they're lapped flat.

Regarding lapping, is a 300 grit ultrasharp diamond plate going to leave too coarse of a finish on a stone like this? If so, what grit would you recommend? I've been meaning to pick up an Atoma but I also have some W&D in various grits.

 

[Wid]

That’ll be fine. Just dress it with your slurry stone afterwards

 

[Gamma]

if you run a pin over it and you can feel it, there is cause for concern. Les lats are brittle, and a crack, even tiny ones, can move without warning. Every time it gets wet/dry, the edges of the fissure will wear a bit and in time even a very tight crack can be felt. If pin feels the crack, so can a razor's edge.
I can't see it or feel it but if It was mine I'd make sure the stone is absolutely bone dry and then I'd drizzle very thin CA glue into it. Very thin nail polish works too. This is not a structural fix, it's just to seal and create a continuous surface. Even if it is out of the way of the blade, sealing the crack off reduces or eliminates any possible 'erosion' effects that may come from use, lapping, etc.

If someone sold that without mentioning the fissure in the written description, that's pretty bogus.

If your diamond plate leaves any felt lines in the surface, just finish lap with 600x w/d.

 

[algebro]

If someone sold that without mentioning the fissure in the written description, that's pretty bogus.

Unfortunately they did not...here is the original written description:

"Vintage Coticule "Les Latneuses" Whetstone & Slurry Stone Finishing Combo

Selling from my personal collection to make some space
Otherwise wouldn't even plan on setting this rare whetstone set​

Rare "Les Latneuses" Set of a decent size bench stone and a matching slurry stone (what we JNAT people call a Tomonagura). On the coticule side, you pretty much can do a bevel set on most knives & straight razors with a thick slurry to finish using the "Dilucot method". However, because this is a "Les Latneuses"you can flip it over to use the special hybrid side (they are famous for this) to bring it to Finish Polish or 10K+.

You pretty much have two different whetstones with this combo

Regular Coticule Side = 2,000 to 8,000+ Grit
Hybrid Side = 10,000+ Grit

Dimensions:
(Main Stone) 4" inches x 1.6" inches x .80" inches
(Slurry Stone) 2.05" inches x 1.15" inches x .85" inches"

I'll try running a pin over it and report back.

 

[bmiller3230]

is it a crack or a manganese line?

 

[JPO]

The hybrid side seems to be quite rough. Maybe the seller didn't consider the hybrid side that important or usable.

 

[algebro]

The pin test was inconclusive; I can't feel the crack with it specifically but it's hard to tell because it doesn't glide smoothly on the non-cracked surface either. Will try lapping with the 300 grit diamond plate and see if that makes it easier to tell.

is it a crack or a manganese line?

Unsure at this point, have never seen a manganese line and google fu is failing me

 

[Empire straights]

I have one that has very small cracks that look like that but they are just quartz veins. If there is a gap put liquid super glue in it, make sure you get down deep, then lap it to get the stuff off the top.

 

[Empire straights]

The pin test was inconclusive; I can't feel the crack with it specifically but it's hard to tell because it doesn't glide smoothly on the non-cracked surface either. Will try lapping with the 300 grit diamond plate and see if that makes it easier to tell.



Unsure at this point, have never seen a manganese line and google fu is failing me

Mine has that uneven feel all across the top too. It's different materials with different harnesses, if you lap it to a really high grit and smooth it with a LL slurry stone on the hybrid side or a hard ark it'll help immensely.

 

[algebro]

Ok, I've lapped with the diamond plate and dressed with the slurry stone and I cannot feel the "crack" with a pin or my nail, so I'm hoping it's just a mineral vein like bmiller3230 and Empire straights suggested. I do now have concerns about this business on one of the sides though:

Do I need to superglue those holes or find some other way to seal them? Not sure if it's showing up in the picture but some of them are kind of deep/wide.

Thanks again!

 

[bmiller3230]

I don't think you really need to worry about the sides much. Coticules don't absorb water nor oil and you can use either on them. Others might have a different opinion on the need to seal them. I haven't sealed any of mine and have used both mediums with no real effect as to being absorbed into the stone. After washing, I can use either water or oil on them with no problem.

 

[JPO]

Ok, I've lapped with the diamond plate and dressed with the slurry stone and I cannot feel the "crack" with a pin or my nail, so I'm hoping it's just a mineral vein like bmiller3230 and Empire straights suggested. I do now have concerns about this business on one of the sides though:

View attachment 1833499

Do I need to superglue those holes or find some other way to seal them? Not sure if it's showing up in the picture but some of them are kind of deep/wide.

Thanks again!

These stones are really brittle. If you bump one of these edges onto something hard you might brake off larger bits that run into your honing surface. I would seal some of them with super glue, or something to be on the safe side.