Here we go again... coticule thread

[Whiskers]

I got a yellow coticule not too long ago. I thought I would give it a run and check it out. I cant get a good edge off of it. The edge seems to get only a tiny bit sharper from dull but smooth. But in comparison, the edge seems to be consistently sharper off of the norton 4k. I've tried the coticule with slurry to keen up the edge before polishing as well as water only after the 4/8k. The edge just seems to dull.

Yes, I am minding the pressure ha.

This is my first foray into the natural stones and I am thinking there is a different technique associated to the coticule than the 4/8k synthetic.

Any tips? Do I really have to do laps with slurry for 20 minutes to keen the edge? It seems like alot to me.

[Neil Miller]

Using slurry with a coticule doesn't make the edge keener - the loose garnets in the slurry actually dull the edge. Using a slurry helps the stone cut faster, but at the expense of a keen edge. Using it with water (or dry) will give the keenest edge.

The edge off of the 4k probably seems sharper - even the edge of a 1k can pop hairs - but it shouldn't perform anything like the edge off of the coticule - two different leagues, one (4k) working at bevel level, the other at refining and polishing. The coticule should normally be used after the 8k.

Are you sure it is lapped properly?

A good stropping or the use of chrome oxide powder will restore the apparent lack of sharpness.

Regards,
Neil

[randydance062449]

When I have used the coticule (water only) after the 8K it has always taken 50 laps or more to produce a keener edge than the 8K. The first 25 laps on the coticule ( water only) seems to dull the edge a bit. I have concluded that the first 25 laps are reshaping the edge/bevel. This I have noticed with not only the coticule but also the Escher type stones and the chinese 12K.
Using a slurry is simply a faster way to get close to a keen edge but then I have to finish with just water only for 50-100 laps to get an edge that I want. Using a slurry shapes the bevel/edge just a little bit differently than if you use water only so when you switch to just water then the first 25-50 laps are reshaping to suit that mode.

Just my $.02,

[BHChieftain]

I hear every coticule is different... for the one I have, I can't get any additional keenness by moving to water only. I either need to go coticule+milky slurry for bevel set, then BBW+milky slurry to get more keeness, then coticule + water to polish. Lately I experimented with Bart's method of using the coticule only-- starting with milky slurry and slowly dilluting until you end up with just water and got a great result-- but it did take me a while to get there...

My personal benchmark for "is a razor sharp enough" is will it shave arm hair when the edge is about 1/4 inch above the skin.


-Chief

[Slartibartfast]

I usually build a milky slurry and gradually dilute it down to water. Then do 50-100 strokes just water.

I have also been playing with doing 30 or so strokes dry, before goign to water only.

Re-reading the coticule Chronicles has gotten me to start experimenting...

Sometimes i will build a heavy slurry to reset the bevel before using the bart "Dilucot" method.

If the edge needs some major work done on it, i will drop down to my dmt and/or naniwa 1k.

[JimmyHAD]

I have a number of coticules and some are better than others for razors. I have always had good luck coming off an 8k and going to a coticule with water only. If you've read Lynn's posts from the past he mentions more than once that he used to use a coticule after the 8k to refine an edge with good results. So it can be done but maybe the particular coticule you have is more suited for something other than finishing a razor.

[Memorael]

how thick is the slurry you are using?

[Howard]

Keep playing with the coticule. Lots of folks get great, shave ready edges from them. Always consider the possibility that the problem might be the razor and not the stone. You might also try different honing techniques as I've noticed that certain razors will sharpen differently off of the same stone. I'm getting great results these days with a side hone technique and with some razors I have to use a few back honing finishing strokes to get the job done. There are lots of variables so keep experimenting.

[Howard]

Are you working under magnification? The naked eye can't really see what's going on at this level. Using a Radio Shack 60x illuminated microscope can change everything. There are all kinds of possibilities why you're getting the results you're getting. Is the bevel set? Is it flat or rounded (I hear they're calling that an "apple seed" bevel now). You want flat. 80 - 90% of the work in honing a blade is getting the bevel ground correctly. After that it's all polishing that narrow little bevel on finer and finer hones. The coticule should, on a well ground bevel, give you a much better shave than off of a Norton 8k.

[gary haywood]

I use aloop 30k that works well with loads of light i've tryed microscopes and i crn't seem to get on with them. Under magnification my loop i look for nice flat bevel pains ans check the cutting edge for nice straight line no jaged bits or tiny micro chips whic i can normaly feel with my thumb. I can easily tellthe differance in scratch pattern from 1k to 4k after that i find it gets harder to tell on finer grits i will have to get microscope from radio shack any chance of sending us the link of what you recomend . I move on at 1k level as soon as the edge grips my thumb and holds and does not slide along the edge and i can shave arm hair i presume this is a godd indicator. I get good shaves of naniwas but i think i just like using the coticule now a days as i only hone for my self and not other people maybe thats all i need unless i have a chip edge or realy dull one