Dumb question about burrs.

Squashfan said:
I am not seeing swarf formation because I don't keep a puddle of oil on top. I keep the stone wet to the touch and that took almost a full 4 oz bottle of oil the first time I used the stone. Besides, this stone eats oil and is very, very porous. I almost think oil just passes through it. I have to keep a plastic tray under it or the counter gets covered in oil.
Anyway, I did sharpen the 154CM blade last night. I put a really nice scratch pattern on the edge. Maybe it is the way I treat the stone by not keeping it really well oiled but the Lansky's scratch pattern looks finer than the medium diamond. Maybe, by not oiling it, the stone becomes finer. I could almost strop this current edge with black compound and call it quits. But where is the fun in that? I am going to strop on plain copy paper to reveal the burr and work it off some more before moving to the next stone.

By the way, this stone is starting to lose its flatness. It is still pretty flat but I can tell there are high spots at the ends with a slightly more aggressive grit. I am not sure that this stone is AlumOx. It is does not seem to be behaving like your descriptions but that may be my fault. But I like it what ever the abrasive is. It does a great job on 154CM.

Thanks,
Charles
Click to expand...

Were you using the coarse or fine side of the stone? Many people might be surprised at the edge one can whip up with a regular combination stone. I used to scoff at the usual description of "coarse side to sharpen a dull edge and grind out chips, and a fine side for a razor's edge", till I figured out how to use one with a nice light touch.

For really porous stones, I will sometimes rub a small amount of vaseline into the top of the stone before applying oil. This holds up for a bunch of jobs before the oil will start to run through again. Or just keep using it the way you are, as you're getting the results you're looking for. In general the more porous the stone the faster it will break down and need lapping, just like a waterstone. This can be the case with either AlumOx or SIC depending on manufacture. Off the fine side of the stone, the break down mud can be reclaimed and used as a stropping compound on paper - works very well just wipe off any loose grit under that paper before use.

I try to do the lower portion of the edge while working on the ends of the stone, and use the center part of the stone for the belly and tip. Especially on waterstones but also on softer combination stones, this will do a good job of keeping the stone flat.

Very good, sounds like you're there.
Martin
 
Finished on the fine stone last night. I stropped on two sheets of plain copy paper but I didn't feel like it worked the edge as much as I would like. So I tried it on a piece of non corrugated cardboard and the result were about the same. So, I went back to the two sheets of copy paper. Then I tried Flexcut gold and, while it improved the worst part of the edge, there wasn't much change overall.

Even after all that I feel like there is still some kind or really, really, tiny burr. I can feel it moving from side to side as I strop but I just can't seem to eliminate it. Still even with that I could cut notebook paper both ways off of the copy paper strop. The edge is a little toothier than I would like but I can fix that later. I am going to carry this edge as is and see how it does.
 
For a time I used to just use a combination SiC stone and kept a small piece of hacksaw blade (all paint removed) in the box. When I wanted to do a quick touch-up, put a few drops of oil on the stone and worked the flat of the sawblade around the stone (mostly on the ends to help correct that dishing). Then I'd carefully mop up the resulting mud by slowly dragging a sheet of paper across the stone. Makes a great minimalist compound and you're at a good spot to try it out. If I just finished doing some grinding I'll simply use the debris from that, and only use the hacksaw when I have to.

Edit to Add:
One last thing re stropping on plain paper - you can use several times the highest amount of pressure you might dare to use on a loaded strop. The abrasives are miniscule and in relatively low quantities. Most of what you're doing is polishing with friction - a light burnishing. On a coarse edge, the multiple sheets do a good job of conforming to the edge irregularities. You might experiment with using a bit of speed and pressure as you finish on plain paper.
 
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I will try stropping with more pressure. My usual pressure is the weight of the blade + a little bit extra when first starting out. Actually, I have plastic tray that I keep under the stone and it full of stone run off. I bet I could rinse it out with a little oil and use that to strop. Also, I will pick up some Vaseline tomorrow.

I got to thinking about the scratch pattern from the fine side and I decided that it was not as fine as I would like. Then it hit me that I will have to work longer on the fine side than on the coarse side. Because the fine side is finer (duh!) than the coarse it takes longer to replace the coarse scratch pattern. I can't believe it took me this long to realize this! I mean I could see what the scratch looked like but it just hadn't hit me quite like this.
 
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