WE diamond stones break in period
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How long before the WE stones break in? Can I expect scratch free bevels after only a few knives?
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It may be possible at least to the naked unaided eye. With lighted magnification even the smallest, finest scratches become apparent. It’s also difficult to avoid introducing new fine scratches while you continue to work on reducing or removing existing scratches. Sometimes it’s a battle of no returns and you have to call it quits and let well enough alone. It gets to the limits of what you can do with out working in a clean room environment.
You need to decide what you’re trying to achieve. Practicle and usable or just for show.
Marc
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I’ve created a handful of truly scratch free bevels. It takes work! I have found that running the stones parallel to the blade seems to really aid the process of polishing though it’s no good for the edge. What I do these days when I want a very highly polished edge goes something like this:
- Profile the blade to an angle that is several degrees lower than the final desired angle with the finest stone I can manage without spending too much time
- Use a slanted stroke that is not quite perpendicular to the edge
- Once the profile is set, make repeated strokes parallel to the edge. I usually rest the handle on the pivot and just slide the stone back and forth along the blade. A stop collar is very helpful for this for two reasons: A) You can vary the position of the stone relative to the edge so you don’t wear out the stones or films in just one spot B) The stone may fall below the edge of the knife when resting the handle on the pivot.
- I continue this motion until all the slanted scratches are gone
- Repeat the process for each grit by first doing slanted strokes and then parallel strokes until all the slanted scratches are gone.
- Continue through the lapping films. This is an important step!
- Once you’ve gone through all the grits, you can then strop the edge for even more polishing (provided you’ve kept your strops free of contamination)
- Adjust the angle to the final angle you want for the knife and create a micro-bevel with the stone of your choice. You only need a few VERY LIGHT strokes to do this
- Optional – reduce the angle again and do a few light strokes with the strop to clean up the edge.
-Clay
Clay, do you use those “scratch free edge” knives? or, are they really for show. I wouldn’t want to scratch one cut something.
Marc
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I don’t think I’ve ever gotten a truly scratch-free bevel finish. I did, however, figure out an easy way to identify the source.
When I inspect the edge after each grit and notice relatively few, but obvious scratches on a polished background, I want to know if they’re from the grit I’m currently using or from the previous grit. Scratches caused by the film or strops you are currently using are caused by a contaminant piece of grit. Scratches caused by the prior grit could be a contaminant or a bit of grit which hasn’t been knocked off by the break-in process.
If you think it’s caused by the film/strop you are using, try reversing the diagonal direction to see if new scratches suddenly appear in that direction as well. Unless the scratches are quite deep, you might (but more likely not) still be able to remove them with the next grit in your progression.
One of the benefits of using PSA film is that if and when it becomes contaminated, you can simply replace the film and start from scratch! That’s a pun, by the way, but it’s a huge plus. If your strops get contaminated, you’ll need to change the substrate or accept that scratches are going to be inevitable from here on out.
If you have a coarse(r) grit contaminant embedded in your strop(s), you can try scrubbing the surface in an attempt to dislodge it.
BTW, I just replaced my 6-micron film, which I believe had worked through at least twenty, and possibly even thirty knives. It was still working well, and showed no loss of grit from the film substrate. I changed them because they just looking really scuzzy. I scrub my films with alcohol and a battery-powered scrubber after every other knife. Don’t know if that contributes to the long life, but it can’t hurt.
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Clay, I actually found myself using the horizontal motion you described above to remove scratches from the previous grit. what I found was since Im only on my 7th knife its going to take awhile to get my stroking motion and stone pressure consistent through the whole circular motion. I find I get deeper scratches when the stone rises vertically at the start of the motion by the heel and the same for a down stroke near the tip. I was noticing deeper scratches in both those areas. So i dropped back 1 grit and started scrubbing horizontally on just those areas. that worked great. I had not seen this mention of horizontal stone movement before until you mentioned your technique above. Thanks for that post for tips towards working towards a scratch free edge.
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Clay, do you use those “scratch free edge” knives? or, are they really for show. I wouldn’t want to scratch one cut something.
Usually it’s just been to discover methods to make it possible and not for actual use.
-Clay
I think those are valid ideas. It may also have to do with the length of the steel horizontally, that your in constant contact with. And possibly because your going across the grain of the steel?
Marc
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I think one factor may have to do with the number of abrasive particles in contact with the metal; During a perpendicular stroke, nearly all particles with contact the blade. During a parallel stroke, only the number of particles that fits within the width of the bevel will contact the blade and they’ll be more or less the same particles through the entire stroke, depending on the curvature of the blade.
-Clay
I started doing the parallel strokes at the end of each progression so when I do the next one I can see the horizontal pattern disappear.
I was on autopilot and started on a film and “sliceola!” wrecked it.
don’t go on autopilot……
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- Profile the blade to an angle that is several degrees lower than the final desired angle with the finest stone I can manage without spending too much time
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