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Slurry undercutting or lack thereof

Jayber Crow

Jayber Crow

I was attempting to hone a J R Torrey blade today on a coticule. I set the bevel with a 1k hone; it passed the toamto and TNT.
I raised a slurry on the coticule and proceeded with 20 x strokes followed by dilution with finger dipped in water.
At first blade was undercutting the slurry, but after about 4th or 5th dilution it was not at certain places. I proceeded anyway for 12 dilutions (thinking I should do something different, but not sure what).
I rinsed the blade and stone and did 60 x strokes on water adding water every 10 strokes or so.
I was not getting any kind of hair severing with HHT at this point.

I was wondering what might cause the loss of undercutting when there had been before.
And, after the dilutions and before x strokes on water is there any sharpness tests anyone does to know whether or not to proceed with x strokes on water only.

Thanks
 
A

aephilli

Jayber Crow said:
I was attempting to hone a J R Torrey blade today on a coticule. I set the bevel with a 1k hone; it passed the toamto and TNT.
I raised a slurry on the coticule and proceeded with 20 x strokes followed by dilution with finger dipped in water.
At first blade was undercutting the slurry, but after about 4th or 5th dilution it was not at certain places. I proceeded anyway for 12 dilutions (thinking I should do something different, but not sure what).
I rinsed the blade and stone and did 60 x strokes on water adding water every 10 strokes or so.
I was not getting any kind of hair severing with HHT at this point.

I was wondering what might cause the loss of undercutting when there had been before.
And, after the dilutions and before x strokes on water is there any sharpness tests anyone does to know whether or not to proceed with x strokes on water only.

Thanks
Click to expand...

Boy, I am glad to hear it ain't just me has this problem. And am waiting eagerly to hear what the soluion is.
 
H

HonerSimpson

Did you go back to the 1k after the TNT?

Short answer; you are diluting too fast. I really like half-strokes, I can do bagfulls of them in no time. Also, a common mistake is to use too little pressure. Did your slurry turn black?
 
B

buca3152

I would lap both bevel setter and coti. And try it again. Losing undercut can be stones need lapping, or stroke is off.
 
Jayber Crow

Jayber Crow

HonerSimpson said:
Did you go back to the 1k after the TNT?

Short answer; you are diluting too fast. I really like half-strokes, I can do bagfulls of them in no time. Also, a common mistake is to use too little pressure. Did your slurry turn black?
Click to expand...

Yes, I do 10 light x strokes after a TNT. Slurry didn't turn black, but I think I was using a fair amount of pressure.

My hone is 40mm x 175mm (1 1/2" x 7") I have tried holding in my hand but am using it on a surface now.
 
H

HonerSimpson

You need to make some swarf there. If your slurry is not turning dark, you are probably not removing enough metal. (The amount will depend on the width of the bevel and whether you tape the spine).
What I would do is sets of half-strokes, say 40/40, at the dilution where the undercut stops, and keep checking with normal x-strokes after every set or two.
I'm sure there will be many opinions.
 
Jayber Crow

Jayber Crow

gary haywood said:
Type in coticule.be. Click on sharpening acadamey. Then read several times dilucot method.

gary
Click to expand...

I've downloaded and printed a hard copy. Since I was doing x-strokes instead of the half strokes it maybe as Honer said, I may be diluting too fast.

@Heespharm My coticule does seem to work better with pressure. I'm not sure what vein it's from. I found it in an antique shop. I posted a picture on another forum when I got it and some suggested it may be la grise or la verte.

Will flatten 1k and coticule and try some more half strokes.

Thanks
 
G

gary haywood

Post picture, if it's la verte there normaly harder stones and easy to reach keen edge. If you read dilucot method it says Bart users bevel setting pressure all the way.
Then finishers with light x strokes. The reason for half strokes is? Number 1 it's quiker, it enables you to do lots of strokes. With normal x strokes it would take say 40 minutes the newer half stroke method would take 15 to 20 or even 10 minutes,

if I was you with a new coticule I would do unicot method several times and see what your coticule is capable of and how she produces a edge.. Then try dilucot when you masterd unicot, unicot method is easier.

gary
 
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G

GC77

I just received my first colicule recently, a La Veinette, and the unicot method (after 1K bevel setting) puts a very keen edge on three different razors I've tried.

Half strokes and lots of them as mentioned with bevel setting pressure was required. I also used new slurry if necessary for the first part of the method. After that I was amazed at how well water laps with less pressure sharpened the blades.
 
Jayber Crow

Jayber Crow

gary haywood said:
Post picture, if it's la verte there normaly harder stones and easy to reach keen edge. If you read dilucot method it says Bart users bevel setting pressure all the way.
Then finishers with light x strokes. The reason for half strokes is? Number 1 it's quiker, it enables you to do lots of strokes. With normal x strokes it would take say 40 minutes the newer half stroke method would take 15 to 20 or even 10 minutes,

if I was you with a new coticule I would do unicot method several times and see what your coticule is capable of and how she produces a edge.. Then try dilucot when you masterd unicot, unicot method is easier.

gary
Click to expand...

Thanks Gary, good advice. I've been trying dilucot, and then failing that going to unicot. I've gotten a couple of razors to shave by doing this. But i probably should get the unicot method down and try to get the best edge with that.
$DSCN0197.jpg$DSCN0244.jpg
 
G

gary haywood

It does look like a la verte, does it feel kind of scratchy when in use fairly hard stone? La berets can be slightly more green it kind of looks like it could be either la grise or la verte. If it's from antique store chances are it's an older mined coticule not newly mined I,m sure it will work well.
If your doing unicot use a good tape, I,d recommend electrical tape scotch 88 heavy duty it's on ebay,

gary
 
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Gamma

Gamma

Regardless of pressure, Not every stone is going to produce dark/blackened slurry/swarf.
I'v e had several Cotis that only ever got to a medium grey.

Another thing is slurry dulling, it does happen and the issue described ' undercut then no undercut' is a symptom.

Not saying thts what is going on - just saying its a possibility.
 
Last edited:
H

HonerSimpson

Yes, I shouldn't have written "black." I meant the production of black swarf, with black swarf plus creamy slurry being some shade of grey.
 
A

aephilli

Gamma said:
...Another thing is slurry dulling, it does bappen and the issue described ' undercut then no undercut' is a symptom.

....
Click to expand...


Bet that is my problem, thanks. I'll start with no undercut then start getting a little suction and great undercut then keep at it too long (admiring that neat looking undercut) between dilutions.
Last nite I did 2 heavy (whole milk) slurries >100 half strokes each to dark grey/black slurry (about the 20th time I'm trying to be sure the bevel is set, lol) then a medium (2% milk) slurry and diluted a finger of water every 30 strokes for about 300 strokes or 10 dilutions. Was still getting good undercut when I ran out of time, almost no slurry, close to pure water by then.
 
Jayber Crow

Jayber Crow

gary haywood said:
It does look like a la verte, does it feel kind of scratchy when in use fairly hard stone? La berets can be slightly more green it kind of looks like it could be either la grise or la verte. If it's from antique store chances are it's an older mined coticule not newly mined I,m sure it will work well.
If your doing unicot use a good tape, I,d recommend electrical tape scotch 88 heavy duty it's on ebay,

gary
Click to expand...

I' say it feels pretty smooth when used with plain water, and I think it's fairly soft. It was well dished when I got it, but didn't take too much to lap flat. The water gets kind of hazy when doing x strokes on plain water.

I'm still trying different pressures to see what happens. I get some 3m 88 tape too, I had been using 3m 700.
 
Lakebound

Lakebound

aephilli said:
Bet that is my problem, thanks. I'll start with no undercut then start getting a little suction and great undercut then keep at it too long (admiring that neat looking undercut) between dilutions.
Last nite I did 2 heavy (whole milk) slurries >100 half strokes each to dark grey/black slurry (about the 20th time I'm trying to be sure the bevel is set, lol) then a medium (2% milk) slurry and diluted a finger of water every 30 strokes for about 300 strokes or 10 dilutions. Was still getting good undercut when I ran out of time, almost no slurry, close to pure water by then.
Click to expand...

Been there myself. You just have to stop yourself and go to the strop and move forward. If you have good, even undercutting and as you call it suction or blade stick, I would call it good and move on.

Frank
 
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